CbC/CbC_gcc: gcc/rtlanal.c comparison

comparison gcc/rtlanal.c @ 0:a06113de4d67

first commit

author	kent <kent@cr.ie.u-ryukyu.ac.jp>
date	Fri, 17 Jul 2009 14:47:48 +0900
parents
children	3bfb6c00c1e0

comparison

equal deleted inserted replaced

--1:000000000000
+:a06113de4d67
+/* Analyze RTL for GNU compiler.
+Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+Free Software Foundation, Inc.
+This file is part of GCC.
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "toplev.h"
+#include "rtl.h"
+#include "hard-reg-set.h"
+#include "insn-config.h"
+#include "recog.h"
+#include "target.h"
+#include "output.h"
+#include "tm_p.h"
+#include "flags.h"
+#include "real.h"
+#include "regs.h"
+#include "function.h"
+#include "df.h"
+#include "tree.h"
+/* Information about a subreg of a hard register.  */
+struct subreg_info
+{
+/* Offset of first hard register involved in the subreg.  */
+int offset;
+/* Number of hard registers involved in the subreg.  */
+int nregs;
+/* Whether this subreg can be represented as a hard reg with the new
+mode.  */
+bool representable_p;
+};
+/* Forward declarations */
+static void set_of_1 (rtx, const_rtx, void *);
+static bool covers_regno_p (const_rtx, unsigned int);
+static bool covers_regno_no_parallel_p (const_rtx, unsigned int);
+static int rtx_referenced_p_1 (rtx *, void *);
+static int computed_jump_p_1 (const_rtx);
+static void parms_set (rtx, const_rtx, void *);
+static void subreg_get_info (unsigned int, enum machine_mode,
+			     unsigned int, enum machine_mode,
+			     struct subreg_info *);
+static unsigned HOST_WIDE_INT cached_nonzero_bits (const_rtx, enum machine_mode,
+const_rtx, enum machine_mode,
+unsigned HOST_WIDE_INT);
+static unsigned HOST_WIDE_INT nonzero_bits1 (const_rtx, enum machine_mode,
+					     const_rtx, enum machine_mode,
+unsigned HOST_WIDE_INT);
+static unsigned int cached_num_sign_bit_copies (const_rtx, enum machine_mode, const_rtx,
+enum machine_mode,
+unsigned int);
+static unsigned int num_sign_bit_copies1 (const_rtx, enum machine_mode, const_rtx,
+enum machine_mode, unsigned int);
+/* Offset of the first 'e', 'E' or 'V' operand for each rtx code, or
+-1 if a code has no such operand.  */
+static int non_rtx_starting_operands[NUM_RTX_CODE];
+/* Bit flags that specify the machine subtype we are compiling for.
+Bits are tested using macros TARGET_... defined in the tm.h file
+and set by `-m...' switches.  Must be defined in rtlanal.c.  */
+int target_flags;
+/* Truncation narrows the mode from SOURCE mode to DESTINATION mode.
+If TARGET_MODE_REP_EXTENDED (DESTINATION, DESTINATION_REP) is
+SIGN_EXTEND then while narrowing we also have to enforce the
+representation and sign-extend the value to mode DESTINATION_REP.
+If the value is already sign-extended to DESTINATION_REP mode we
+can just switch to DESTINATION mode on it.  For each pair of
+integral modes SOURCE and DESTINATION, when truncating from SOURCE
+to DESTINATION, NUM_SIGN_BIT_COPIES_IN_REP[SOURCE][DESTINATION]
+contains the number of high-order bits in SOURCE that have to be
+copies of the sign-bit so that we can do this mode-switch to
+DESTINATION.  */
+static unsigned int
+num_sign_bit_copies_in_rep[MAX_MODE_INT + 1][MAX_MODE_INT + 1];
+/* Return 1 if the value of X is unstable
+(would be different at a different point in the program).
+The frame pointer, arg pointer, etc. are considered stable
+(within one function) and so is anything marked `unchanging'.  */
+int
+rtx_unstable_p (const_rtx x)
+{
+const RTX_CODE code = GET_CODE (x);
+int i;
+const char *fmt;
+switch (code)
+{
+case MEM:
+return !MEM_READONLY_P (x) || rtx_unstable_p (XEXP (x, 0));
+case CONST:
+case CONST_INT:
+case CONST_DOUBLE:
+case CONST_FIXED:
+case CONST_VECTOR:
+case SYMBOL_REF:
+case LABEL_REF:
+return 0;
+case REG:
+/* As in rtx_varies_p, we have to use the actual rtx, not reg number.  */
+if (x == frame_pointer_rtx || x == hard_frame_pointer_rtx
+	  /* The arg pointer varies if it is not a fixed register.  */
+	  || (x == arg_pointer_rtx && fixed_regs[ARG_POINTER_REGNUM]))
+	return 0;
+#ifndef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
+/* ??? When call-clobbered, the value is stable modulo the restore
+	 that must happen after a call.  This currently screws up local-alloc
+	 into believing that the restore is not needed.  */
+if (x == pic_offset_table_rtx)
+	return 0;
+#endif
+return 1;
+case ASM_OPERANDS:
+if (MEM_VOLATILE_P (x))
+	return 1;
+/* Fall through.  */
+default:
+break;
+}
+fmt = GET_RTX_FORMAT (code);
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+if (fmt[i] == 'e')
+{
+	if (rtx_unstable_p (XEXP (x, i)))
+	  return 1;
+}
+else if (fmt[i] == 'E')
+{
+	int j;
+	for (j = 0; j < XVECLEN (x, i); j++)
+	  if (rtx_unstable_p (XVECEXP (x, i, j)))
+	    return 1;
+}
+return 0;
+}
+/* Return 1 if X has a value that can vary even between two
+executions of the program.  0 means X can be compared reliably
+against certain constants or near-constants.
+FOR_ALIAS is nonzero if we are called from alias analysis; if it is
+zero, we are slightly more conservative.
+The frame pointer and the arg pointer are considered constant.  */
+bool
+rtx_varies_p (const_rtx x, bool for_alias)
+{
+RTX_CODE code;
+int i;
+const char *fmt;
+if (!x)
+return 0;
+code = GET_CODE (x);
+switch (code)
+{
+case MEM:
+return !MEM_READONLY_P (x) || rtx_varies_p (XEXP (x, 0), for_alias);
+case CONST:
+case CONST_INT:
+case CONST_DOUBLE:
+case CONST_FIXED:
+case CONST_VECTOR:
+case SYMBOL_REF:
+case LABEL_REF:
+return 0;
+case REG:
+/* Note that we have to test for the actual rtx used for the frame
+	 and arg pointers and not just the register number in case we have
+	 eliminated the frame and/or arg pointer and are using it
+	 for pseudos.  */
+if (x == frame_pointer_rtx || x == hard_frame_pointer_rtx
+	  /* The arg pointer varies if it is not a fixed register.  */
+	  || (x == arg_pointer_rtx && fixed_regs[ARG_POINTER_REGNUM]))
+	return 0;
+if (x == pic_offset_table_rtx
+#ifdef PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
+	  /* ??? When call-clobbered, the value is stable modulo the restore
+	     that must happen after a call.  This currently screws up
+	     local-alloc into believing that the restore is not needed, so we
+	     must return 0 only if we are called from alias analysis.  */
+	  && for_alias
+#endif
+	  )
+	return 0;
+return 1;
+case LO_SUM:
+/* The operand 0 of a LO_SUM is considered constant
+	 (in fact it is related specifically to operand 1)
+	 during alias analysis.  */
+return (! for_alias && rtx_varies_p (XEXP (x, 0), for_alias))
+	     || rtx_varies_p (XEXP (x, 1), for_alias);
+case ASM_OPERANDS:
+if (MEM_VOLATILE_P (x))
+	return 1;
+/* Fall through.  */
+default:
+break;
+}
+fmt = GET_RTX_FORMAT (code);
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+if (fmt[i] == 'e')
+{
+	if (rtx_varies_p (XEXP (x, i), for_alias))
+	  return 1;
+}
+else if (fmt[i] == 'E')
+{
+	int j;
+	for (j = 0; j < XVECLEN (x, i); j++)
+	  if (rtx_varies_p (XVECEXP (x, i, j), for_alias))
+	    return 1;
+}
+return 0;
+}
+/* Return nonzero if the use of X as an address in a MEM can cause a trap.
+MODE is the mode of the MEM (not that of X) and UNALIGNED_MEMS controls
+whether nonzero is returned for unaligned memory accesses on strict
+alignment machines.  */
+static int
+rtx_addr_can_trap_p_1 (const_rtx x, HOST_WIDE_INT offset, HOST_WIDE_INT size,
+		       enum machine_mode mode, bool unaligned_mems)
+{
+enum rtx_code code = GET_CODE (x);
+if (STRICT_ALIGNMENT
+&& unaligned_mems
+&& GET_MODE_SIZE (mode) != 0)
+{
+HOST_WIDE_INT actual_offset = offset;
+#ifdef SPARC_STACK_BOUNDARY_HACK
+/* ??? The SPARC port may claim a STACK_BOUNDARY higher than
+	     the real alignment of %sp.  However, when it does this, the
+	     alignment of %sp+STACK_POINTER_OFFSET is STACK_BOUNDARY.  */
+if (SPARC_STACK_BOUNDARY_HACK
+	  && (x == stack_pointer_rtx || x == hard_frame_pointer_rtx))
+	actual_offset -= STACK_POINTER_OFFSET;
+#endif
+if (actual_offset % GET_MODE_SIZE (mode) != 0)
+	return 1;
+}
+switch (code)
+{
+case SYMBOL_REF:
+if (SYMBOL_REF_WEAK (x))
+	return 1;
+if (!CONSTANT_POOL_ADDRESS_P (x))
+	{
+	  tree decl;
+	  HOST_WIDE_INT decl_size;
+	  if (offset < 0)
+	    return 1;
+	  if (size == 0)
+	    size = GET_MODE_SIZE (mode);
+	  if (size == 0)
+	    return offset != 0;
+	  /* If the size of the access or of the symbol is unknown,
+	     assume the worst.  */
+	  decl = SYMBOL_REF_DECL (x);
+	  /* Else check that the access is in bounds.  TODO: restructure
+	     expr_size/lhd_expr_size/int_expr_size and just use the latter.  */
+	  if (!decl)
+	    decl_size = -1;
+	  else if (DECL_P (decl) && DECL_SIZE_UNIT (decl))
+	    decl_size = (host_integerp (DECL_SIZE_UNIT (decl), 0)
+			 ? tree_low_cst (DECL_SIZE_UNIT (decl), 0)
+			 : -1);
+	  else if (TREE_CODE (decl) == STRING_CST)
+	    decl_size = TREE_STRING_LENGTH (decl);
+	  else if (TYPE_SIZE_UNIT (TREE_TYPE (decl)))
+	    decl_size = int_size_in_bytes (TREE_TYPE (decl));
+	  else
+	    decl_size = -1;
+	  return (decl_size <= 0 ? offset != 0 : offset + size > decl_size);
+}
+return 0;
+case LABEL_REF:
+return 0;
+case REG:
+/* As in rtx_varies_p, we have to use the actual rtx, not reg number.  */
+if (x == frame_pointer_rtx || x == hard_frame_pointer_rtx
+	  || x == stack_pointer_rtx
+	  /* The arg pointer varies if it is not a fixed register.  */
+	  || (x == arg_pointer_rtx && fixed_regs[ARG_POINTER_REGNUM]))
+	return 0;
+/* All of the virtual frame registers are stack references.  */
+if (REGNO (x) >= FIRST_VIRTUAL_REGISTER
+	  && REGNO (x) <= LAST_VIRTUAL_REGISTER)
+	return 0;
+return 1;
+case CONST:
+return rtx_addr_can_trap_p_1 (XEXP (x, 0), offset, size,
+				    mode, unaligned_mems);
+case PLUS:
+/* An address is assumed not to trap if:
+- it is the pic register plus a constant.  */
+if (XEXP (x, 0) == pic_offset_table_rtx && CONSTANT_P (XEXP (x, 1)))
+	return 0;
+/* - or it is an address that can't trap plus a constant integer,
+	   with the proper remainder modulo the mode size if we are
+	   considering unaligned memory references.  */
+if (GET_CODE (XEXP (x, 1)) == CONST_INT
+	  && !rtx_addr_can_trap_p_1 (XEXP (x, 0), offset + INTVAL (XEXP (x, 1)),
+				     size, mode, unaligned_mems))
+	return 0;
+return 1;
+case LO_SUM:
+case PRE_MODIFY:
+return rtx_addr_can_trap_p_1 (XEXP (x, 1), offset, size,
+				    mode, unaligned_mems);
+case PRE_DEC:
+case PRE_INC:
+case POST_DEC:
+case POST_INC:
+case POST_MODIFY:
+return rtx_addr_can_trap_p_1 (XEXP (x, 0), offset, size,
+				    mode, unaligned_mems);
+default:
+break;
+}
+/* If it isn't one of the case above, it can cause a trap.  */
+return 1;
+}
+/* Return nonzero if the use of X as an address in a MEM can cause a trap.  */
+int
+rtx_addr_can_trap_p (const_rtx x)
+{
+return rtx_addr_can_trap_p_1 (x, 0, 0, VOIDmode, false);
+}
+/* Return true if X is an address that is known to not be zero.  */
+bool
+nonzero_address_p (const_rtx x)
+{
+const enum rtx_code code = GET_CODE (x);
+switch (code)
+{
+case SYMBOL_REF:
+return !SYMBOL_REF_WEAK (x);
+case LABEL_REF:
+return true;
+case REG:
+/* As in rtx_varies_p, we have to use the actual rtx, not reg number.  */
+if (x == frame_pointer_rtx || x == hard_frame_pointer_rtx
+	  || x == stack_pointer_rtx
+	  || (x == arg_pointer_rtx && fixed_regs[ARG_POINTER_REGNUM]))
+	return true;
+/* All of the virtual frame registers are stack references.  */
+if (REGNO (x) >= FIRST_VIRTUAL_REGISTER
+	  && REGNO (x) <= LAST_VIRTUAL_REGISTER)
+	return true;
+return false;
+case CONST:
+return nonzero_address_p (XEXP (x, 0));
+case PLUS:
+if (GET_CODE (XEXP (x, 1)) == CONST_INT)
+return nonzero_address_p (XEXP (x, 0));
+/* Handle PIC references.  */
+else if (XEXP (x, 0) == pic_offset_table_rtx
+	       && CONSTANT_P (XEXP (x, 1)))
+	return true;
+return false;
+case PRE_MODIFY:
+/* Similar to the above; allow positive offsets.  Further, since
+	 auto-inc is only allowed in memories, the register must be a
+	 pointer.  */
+if (GET_CODE (XEXP (x, 1)) == CONST_INT
+	  && INTVAL (XEXP (x, 1)) > 0)
+	return true;
+return nonzero_address_p (XEXP (x, 0));
+case PRE_INC:
+/* Similarly.  Further, the offset is always positive.  */
+return true;
+case PRE_DEC:
+case POST_DEC:
+case POST_INC:
+case POST_MODIFY:
+return nonzero_address_p (XEXP (x, 0));
+case LO_SUM:
+return nonzero_address_p (XEXP (x, 1));
+default:
+break;
+}
+/* If it isn't one of the case above, might be zero.  */
+return false;
+}
+/* Return 1 if X refers to a memory location whose address
+cannot be compared reliably with constant addresses,
+or if X refers to a BLKmode memory object.
+FOR_ALIAS is nonzero if we are called from alias analysis; if it is
+zero, we are slightly more conservative.  */
+bool
+rtx_addr_varies_p (const_rtx x, bool for_alias)
+{
+enum rtx_code code;
+int i;
+const char *fmt;
+if (x == 0)
+return 0;
+code = GET_CODE (x);
+if (code == MEM)
+return GET_MODE (x) == BLKmode || rtx_varies_p (XEXP (x, 0), for_alias);
+fmt = GET_RTX_FORMAT (code);
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+if (fmt[i] == 'e')
+{
+	if (rtx_addr_varies_p (XEXP (x, i), for_alias))
+	  return 1;
+}
+else if (fmt[i] == 'E')
+{
+	int j;
+	for (j = 0; j < XVECLEN (x, i); j++)
+	  if (rtx_addr_varies_p (XVECEXP (x, i, j), for_alias))
+	    return 1;
+}
+return 0;
+}
+/* Return the value of the integer term in X, if one is apparent;
+otherwise return 0.
+Only obvious integer terms are detected.
+This is used in cse.c with the `related_value' field.  */
+HOST_WIDE_INT
+get_integer_term (const_rtx x)
+{
+if (GET_CODE (x) == CONST)
+x = XEXP (x, 0);
+if (GET_CODE (x) == MINUS
+&& GET_CODE (XEXP (x, 1)) == CONST_INT)
+return - INTVAL (XEXP (x, 1));
+if (GET_CODE (x) == PLUS
+&& GET_CODE (XEXP (x, 1)) == CONST_INT)
+return INTVAL (XEXP (x, 1));
+return 0;
+}
+/* If X is a constant, return the value sans apparent integer term;
+otherwise return 0.
+Only obvious integer terms are detected.  */
+rtx
+get_related_value (const_rtx x)
+{
+if (GET_CODE (x) != CONST)
+return 0;
+x = XEXP (x, 0);
+if (GET_CODE (x) == PLUS
+&& GET_CODE (XEXP (x, 1)) == CONST_INT)
+return XEXP (x, 0);
+else if (GET_CODE (x) == MINUS
+	   && GET_CODE (XEXP (x, 1)) == CONST_INT)
+return XEXP (x, 0);
+return 0;
+}
+/* Return true if SYMBOL is a SYMBOL_REF and OFFSET + SYMBOL points
+to somewhere in the same object or object_block as SYMBOL.  */
+bool
+offset_within_block_p (const_rtx symbol, HOST_WIDE_INT offset)
+{
+tree decl;
+if (GET_CODE (symbol) != SYMBOL_REF)
+return false;
+if (offset == 0)
+return true;
+if (offset > 0)
+{
+if (CONSTANT_POOL_ADDRESS_P (symbol)
+	  && offset < (int) GET_MODE_SIZE (get_pool_mode (symbol)))
+	return true;
+decl = SYMBOL_REF_DECL (symbol);
+if (decl && offset < int_size_in_bytes (TREE_TYPE (decl)))
+	return true;
+}
+if (SYMBOL_REF_HAS_BLOCK_INFO_P (symbol)
+&& SYMBOL_REF_BLOCK (symbol)
+&& SYMBOL_REF_BLOCK_OFFSET (symbol) >= 0
+&& ((unsigned HOST_WIDE_INT) offset + SYMBOL_REF_BLOCK_OFFSET (symbol)
+	  < (unsigned HOST_WIDE_INT) SYMBOL_REF_BLOCK (symbol)->size))
+return true;
+return false;
+}
+/* Split X into a base and a constant offset, storing them in *BASE_OUT
+and *OFFSET_OUT respectively.  */
+void
+split_const (rtx x, rtx *base_out, rtx *offset_out)
+{
+if (GET_CODE (x) == CONST)
+{
+x = XEXP (x, 0);
+if (GET_CODE (x) == PLUS && GET_CODE (XEXP (x, 1)) == CONST_INT)
+	{
+	  *base_out = XEXP (x, 0);
+	  *offset_out = XEXP (x, 1);
+	  return;
+	}
+}
+*base_out = x;
+*offset_out = const0_rtx;
+}
+/* Return the number of places FIND appears within X.  If COUNT_DEST is
+zero, we do not count occurrences inside the destination of a SET.  */
+int
+count_occurrences (const_rtx x, const_rtx find, int count_dest)
+{
+int i, j;
+enum rtx_code code;
+const char *format_ptr;
+int count;
+if (x == find)
+return 1;
+code = GET_CODE (x);
+switch (code)
+{
+case REG:
+case CONST_INT:
+case CONST_DOUBLE:
+case CONST_FIXED:
+case CONST_VECTOR:
+case SYMBOL_REF:
+case CODE_LABEL:
+case PC:
+case CC0:
+return 0;
+case EXPR_LIST:
+count = count_occurrences (XEXP (x, 0), find, count_dest);
+if (XEXP (x, 1))
+	count += count_occurrences (XEXP (x, 1), find, count_dest);
+return count;
+case MEM:
+if (MEM_P (find) && rtx_equal_p (x, find))
+	return 1;
+break;
+case SET:
+if (SET_DEST (x) == find && ! count_dest)
+	return count_occurrences (SET_SRC (x), find, count_dest);
+break;
+default:
+break;
+}
+format_ptr = GET_RTX_FORMAT (code);
+count = 0;
+for (i = 0; i < GET_RTX_LENGTH (code); i++)
+{
+switch (*format_ptr++)
+	{
+	case 'e':
+	  count += count_occurrences (XEXP (x, i), find, count_dest);
+	  break;
+	case 'E':
+	  for (j = 0; j < XVECLEN (x, i); j++)
+	    count += count_occurrences (XVECEXP (x, i, j), find, count_dest);
+	  break;
+	}
+}
+return count;
+}
+/* Nonzero if register REG appears somewhere within IN.
+Also works if REG is not a register; in this case it checks
+for a subexpression of IN that is Lisp "equal" to REG.  */
+int
+reg_mentioned_p (const_rtx reg, const_rtx in)
+{
+const char *fmt;
+int i;
+enum rtx_code code;
+if (in == 0)
+return 0;
+if (reg == in)
+return 1;
+if (GET_CODE (in) == LABEL_REF)
+return reg == XEXP (in, 0);
+code = GET_CODE (in);
+switch (code)
+{
+/* Compare registers by number.  */
+case REG:
+return REG_P (reg) && REGNO (in) == REGNO (reg);
+/* These codes have no constituent expressions
+	 and are unique.  */
+case SCRATCH:
+case CC0:
+case PC:
+return 0;
+case CONST_INT:
+case CONST_VECTOR:
+case CONST_DOUBLE:
+case CONST_FIXED:
+/* These are kept unique for a given value.  */
+return 0;
+default:
+break;
+}
+if (GET_CODE (reg) == code && rtx_equal_p (reg, in))
+return 1;
+fmt = GET_RTX_FORMAT (code);
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+{
+if (fmt[i] == 'E')
+	{
+	  int j;
+	  for (j = XVECLEN (in, i) - 1; j >= 0; j--)
+	    if (reg_mentioned_p (reg, XVECEXP (in, i, j)))
+	      return 1;
+	}
+else if (fmt[i] == 'e'
+	       && reg_mentioned_p (reg, XEXP (in, i)))
+	return 1;
+}
+return 0;
+}
+/* Return 1 if in between BEG and END, exclusive of BEG and END, there is
+no CODE_LABEL insn.  */
+int
+no_labels_between_p (const_rtx beg, const_rtx end)
+{
+rtx p;
+if (beg == end)
+return 0;
+for (p = NEXT_INSN (beg); p != end; p = NEXT_INSN (p))
+if (LABEL_P (p))
+return 0;
+return 1;
+}
+/* Nonzero if register REG is used in an insn between
+FROM_INSN and TO_INSN (exclusive of those two).  */
+int
+reg_used_between_p (const_rtx reg, const_rtx from_insn, const_rtx to_insn)
+{
+rtx insn;
+if (from_insn == to_insn)
+return 0;
+for (insn = NEXT_INSN (from_insn); insn != to_insn; insn = NEXT_INSN (insn))
+if (INSN_P (insn)
+	&& (reg_overlap_mentioned_p (reg, PATTERN (insn))
+	   || (CALL_P (insn) && find_reg_fusage (insn, USE, reg))))
+return 1;
+return 0;
+}
+/* Nonzero if the old value of X, a register, is referenced in BODY.  If X
+is entirely replaced by a new value and the only use is as a SET_DEST,
+we do not consider it a reference.  */
+int
+reg_referenced_p (const_rtx x, const_rtx body)
+{
+int i;
+switch (GET_CODE (body))
+{
+case SET:
+if (reg_overlap_mentioned_p (x, SET_SRC (body)))
+	return 1;
+/* If the destination is anything other than CC0, PC, a REG or a SUBREG
+	 of a REG that occupies all of the REG, the insn references X if
+	 it is mentioned in the destination.  */
+if (GET_CODE (SET_DEST (body)) != CC0
+	  && GET_CODE (SET_DEST (body)) != PC
+	  && !REG_P (SET_DEST (body))
+	  && ! (GET_CODE (SET_DEST (body)) == SUBREG
+		&& REG_P (SUBREG_REG (SET_DEST (body)))
+		&& (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (body))))
+		      + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)
+		    == ((GET_MODE_SIZE (GET_MODE (SET_DEST (body)))
+			 + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)))
+	  && reg_overlap_mentioned_p (x, SET_DEST (body)))
+	return 1;
+return 0;
+case ASM_OPERANDS:
+for (i = ASM_OPERANDS_INPUT_LENGTH (body) - 1; i >= 0; i--)
+	if (reg_overlap_mentioned_p (x, ASM_OPERANDS_INPUT (body, i)))
+	  return 1;
+return 0;
+case CALL:
+case USE:
+case IF_THEN_ELSE:
+return reg_overlap_mentioned_p (x, body);
+case TRAP_IF:
+return reg_overlap_mentioned_p (x, TRAP_CONDITION (body));
+case PREFETCH:
+return reg_overlap_mentioned_p (x, XEXP (body, 0));
+case UNSPEC:
+case UNSPEC_VOLATILE:
+for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
+	if (reg_overlap_mentioned_p (x, XVECEXP (body, 0, i)))
+	  return 1;
+return 0;
+case PARALLEL:
+for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
+	if (reg_referenced_p (x, XVECEXP (body, 0, i)))
+	  return 1;
+return 0;
+case CLOBBER:
+if (MEM_P (XEXP (body, 0)))
+	if (reg_overlap_mentioned_p (x, XEXP (XEXP (body, 0), 0)))
+	  return 1;
+return 0;
+case COND_EXEC:
+if (reg_overlap_mentioned_p (x, COND_EXEC_TEST (body)))
+	return 1;
+return reg_referenced_p (x, COND_EXEC_CODE (body));
+default:
+return 0;
+}
+}
+/* Nonzero if register REG is set or clobbered in an insn between
+FROM_INSN and TO_INSN (exclusive of those two).  */
+int
+reg_set_between_p (const_rtx reg, const_rtx from_insn, const_rtx to_insn)
+{
+const_rtx insn;
+if (from_insn == to_insn)
+return 0;
+for (insn = NEXT_INSN (from_insn); insn != to_insn; insn = NEXT_INSN (insn))
+if (INSN_P (insn) && reg_set_p (reg, insn))
+return 1;
+return 0;
+}
+/* Internals of reg_set_between_p.  */
+int
+reg_set_p (const_rtx reg, const_rtx insn)
+{
+/* We can be passed an insn or part of one.  If we are passed an insn,
+check if a side-effect of the insn clobbers REG.  */
+if (INSN_P (insn)
+&& (FIND_REG_INC_NOTE (insn, reg)
+	  || (CALL_P (insn)
+	      && ((REG_P (reg)
+		   && REGNO (reg) < FIRST_PSEUDO_REGISTER
+		   && overlaps_hard_reg_set_p (regs_invalidated_by_call,
+					       GET_MODE (reg), REGNO (reg)))
+		  || MEM_P (reg)
+		  || find_reg_fusage (insn, CLOBBER, reg)))))
+return 1;
+return set_of (reg, insn) != NULL_RTX;
+}
+/* Similar to reg_set_between_p, but check all registers in X.  Return 0
+only if none of them are modified between START and END.  Return 1 if
+X contains a MEM; this routine does use memory aliasing.  */
+int
+modified_between_p (const_rtx x, const_rtx start, const_rtx end)
+{
+const enum rtx_code code = GET_CODE (x);
+const char *fmt;
+int i, j;
+rtx insn;
+if (start == end)
+return 0;
+switch (code)
+{
+case CONST_INT:
+case CONST_DOUBLE:
+case CONST_FIXED:
+case CONST_VECTOR:
+case CONST:
+case SYMBOL_REF:
+case LABEL_REF:
+return 0;
+case PC:
+case CC0:
+return 1;
+case MEM:
+if (modified_between_p (XEXP (x, 0), start, end))
+	return 1;
+if (MEM_READONLY_P (x))
+	return 0;
+for (insn = NEXT_INSN (start); insn != end; insn = NEXT_INSN (insn))
+	if (memory_modified_in_insn_p (x, insn))
+	  return 1;
+return 0;
+break;
+case REG:
+return reg_set_between_p (x, start, end);
+default:
+break;
+}
+fmt = GET_RTX_FORMAT (code);
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+{
+if (fmt[i] == 'e' && modified_between_p (XEXP (x, i), start, end))
+	return 1;
+else if (fmt[i] == 'E')
+	for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+	  if (modified_between_p (XVECEXP (x, i, j), start, end))
+	    return 1;
+}
+return 0;
+}
+/* Similar to reg_set_p, but check all registers in X.  Return 0 only if none
+of them are modified in INSN.  Return 1 if X contains a MEM; this routine
+does use memory aliasing.  */
+int
+modified_in_p (const_rtx x, const_rtx insn)
+{
+const enum rtx_code code = GET_CODE (x);
+const char *fmt;
+int i, j;
+switch (code)
+{
+case CONST_INT:
+case CONST_DOUBLE:
+case CONST_FIXED:
+case CONST_VECTOR:
+case CONST:
+case SYMBOL_REF:
+case LABEL_REF:
+return 0;
+case PC:
+case CC0:
+return 1;
+case MEM:
+if (modified_in_p (XEXP (x, 0), insn))
+	return 1;
+if (MEM_READONLY_P (x))
+	return 0;
+if (memory_modified_in_insn_p (x, insn))
+	return 1;
+return 0;
+break;
+case REG:
+return reg_set_p (x, insn);
+default:
+break;
+}
+fmt = GET_RTX_FORMAT (code);
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+{
+if (fmt[i] == 'e' && modified_in_p (XEXP (x, i), insn))
+	return 1;
+else if (fmt[i] == 'E')
+	for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+	  if (modified_in_p (XVECEXP (x, i, j), insn))
+	    return 1;
+}
+return 0;
+}
+/* Helper function for set_of.  */
+struct set_of_data
+{
+const_rtx found;
+const_rtx pat;
+};
+static void
+set_of_1 (rtx x, const_rtx pat, void *data1)
+{
+struct set_of_data *const data = (struct set_of_data *) (data1);
+if (rtx_equal_p (x, data->pat)
+|| (!MEM_P (x) && reg_overlap_mentioned_p (data->pat, x)))
+data->found = pat;
+}
+/* Give an INSN, return a SET or CLOBBER expression that does modify PAT
+(either directly or via STRICT_LOW_PART and similar modifiers).  */
+const_rtx
+set_of (const_rtx pat, const_rtx insn)
+{
+struct set_of_data data;
+data.found = NULL_RTX;
+data.pat = pat;
+note_stores (INSN_P (insn) ? PATTERN (insn) : insn, set_of_1, &data);
+return data.found;
+}
+/* Given an INSN, return a SET expression if this insn has only a single SET.
+It may also have CLOBBERs, USEs, or SET whose output
+will not be used, which we ignore.  */
+rtx
+single_set_2 (const_rtx insn, const_rtx pat)
+{
+rtx set = NULL;
+int set_verified = 1;
+int i;
+if (GET_CODE (pat) == PARALLEL)
+{
+for (i = 0; i < XVECLEN (pat, 0); i++)
+	{
+	  rtx sub = XVECEXP (pat, 0, i);
+	  switch (GET_CODE (sub))
+	    {
+	    case USE:
+	    case CLOBBER:
+	      break;
+	    case SET:
+	      /* We can consider insns having multiple sets, where all
+		 but one are dead as single set insns.  In common case
+		 only single set is present in the pattern so we want
+		 to avoid checking for REG_UNUSED notes unless necessary.
+		 When we reach set first time, we just expect this is
+		 the single set we are looking for and only when more
+		 sets are found in the insn, we check them.  */
+	      if (!set_verified)
+		{
+		  if (find_reg_note (insn, REG_UNUSED, SET_DEST (set))
+		      && !side_effects_p (set))
+		    set = NULL;
+		  else
+		    set_verified = 1;
+		}
+	      if (!set)
+		set = sub, set_verified = 0;
+	      else if (!find_reg_note (insn, REG_UNUSED, SET_DEST (sub))
+		       || side_effects_p (sub))
+		return NULL_RTX;
+	      break;
+	    default:
+	      return NULL_RTX;
+	    }
+	}
+}
+return set;
+}
+/* Given an INSN, return nonzero if it has more than one SET, else return
+zero.  */
+int
+multiple_sets (const_rtx insn)
+{
+int found;
+int i;
+/* INSN must be an insn.  */
+if (! INSN_P (insn))
+return 0;
+/* Only a PARALLEL can have multiple SETs.  */
+if (GET_CODE (PATTERN (insn)) == PARALLEL)
+{
+for (i = 0, found = 0; i < XVECLEN (PATTERN (insn), 0); i++)
+	if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == SET)
+	  {
+	    /* If we have already found a SET, then return now.  */
+	    if (found)
+	      return 1;
+	    else
+	      found = 1;
+	  }
+}
+/* Either zero or one SET.  */
+return 0;
+}
+/* Return nonzero if the destination of SET equals the source
+and there are no side effects.  */
+int
+set_noop_p (const_rtx set)
+{
+rtx src = SET_SRC (set);
+rtx dst = SET_DEST (set);
+if (dst == pc_rtx && src == pc_rtx)
+return 1;
+if (MEM_P (dst) && MEM_P (src))
+return rtx_equal_p (dst, src) && !side_effects_p (dst);
+if (GET_CODE (dst) == ZERO_EXTRACT)
+return rtx_equal_p (XEXP (dst, 0), src)
+	   && ! BYTES_BIG_ENDIAN && XEXP (dst, 2) == const0_rtx
+	   && !side_effects_p (src);
+if (GET_CODE (dst) == STRICT_LOW_PART)
+dst = XEXP (dst, 0);
+if (GET_CODE (src) == SUBREG && GET_CODE (dst) == SUBREG)
+{
+if (SUBREG_BYTE (src) != SUBREG_BYTE (dst))
+	return 0;
+src = SUBREG_REG (src);
+dst = SUBREG_REG (dst);
+}
+return (REG_P (src) && REG_P (dst)
+	  && REGNO (src) == REGNO (dst));
+}
+/* Return nonzero if an insn consists only of SETs, each of which only sets a
+value to itself.  */
+int
+noop_move_p (const_rtx insn)
+{
+rtx pat = PATTERN (insn);
+if (INSN_CODE (insn) == NOOP_MOVE_INSN_CODE)
+return 1;
+/* Insns carrying these notes are useful later on.  */
+if (find_reg_note (insn, REG_EQUAL, NULL_RTX))
+return 0;
+if (GET_CODE (pat) == SET && set_noop_p (pat))
+return 1;
+if (GET_CODE (pat) == PARALLEL)
+{
+int i;
+/* If nothing but SETs of registers to themselves,
+	 this insn can also be deleted.  */
+for (i = 0; i < XVECLEN (pat, 0); i++)
+	{
+	  rtx tem = XVECEXP (pat, 0, i);
+	  if (GET_CODE (tem) == USE
+	      || GET_CODE (tem) == CLOBBER)
+	    continue;
+	  if (GET_CODE (tem) != SET || ! set_noop_p (tem))
+	    return 0;
+	}
+return 1;
+}
+return 0;
+}
+/* Return the last thing that X was assigned from before *PINSN.  If VALID_TO
+is not NULL_RTX then verify that the object is not modified up to VALID_TO.
+If the object was modified, if we hit a partial assignment to X, or hit a
+CODE_LABEL first, return X.  If we found an assignment, update *PINSN to
+point to it.  ALLOW_HWREG is set to 1 if hardware registers are allowed to
+be the src.  */
+rtx
+find_last_value (rtx x, rtx *pinsn, rtx valid_to, int allow_hwreg)
+{
+rtx p;
+for (p = PREV_INSN (*pinsn); p && !LABEL_P (p);
+p = PREV_INSN (p))
+if (INSN_P (p))
+{
+	rtx set = single_set (p);
+	rtx note = find_reg_note (p, REG_EQUAL, NULL_RTX);
+	if (set && rtx_equal_p (x, SET_DEST (set)))
+	  {
+	    rtx src = SET_SRC (set);
+	    if (note && GET_CODE (XEXP (note, 0)) != EXPR_LIST)
+	      src = XEXP (note, 0);
+	    if ((valid_to == NULL_RTX
+		 || ! modified_between_p (src, PREV_INSN (p), valid_to))
+		/* Reject hard registers because we don't usually want
+		   to use them; we'd rather use a pseudo.  */
+		&& (! (REG_P (src)
+		      && REGNO (src) < FIRST_PSEUDO_REGISTER) || allow_hwreg))
+	      {
+		*pinsn = p;
+		return src;
+	      }
+	  }
+	/* If set in non-simple way, we don't have a value.  */
+	if (reg_set_p (x, p))
+	  break;
+}
+return x;
+}
+/* Return nonzero if register in range [REGNO, ENDREGNO)
+appears either explicitly or implicitly in X
+other than being stored into.
+References contained within the substructure at LOC do not count.
+LOC may be zero, meaning don't ignore anything.  */
+int
+refers_to_regno_p (unsigned int regno, unsigned int endregno, const_rtx x,
+		   rtx *loc)
+{
+int i;
+unsigned int x_regno;
+RTX_CODE code;
+const char *fmt;
+repeat:
+/* The contents of a REG_NONNEG note is always zero, so we must come here
+upon repeat in case the last REG_NOTE is a REG_NONNEG note.  */
+if (x == 0)
+return 0;
+code = GET_CODE (x);
+switch (code)
+{
+case REG:
+x_regno = REGNO (x);
+/* If we modifying the stack, frame, or argument pointer, it will
+	 clobber a virtual register.  In fact, we could be more precise,
+	 but it isn't worth it.  */
+if ((x_regno == STACK_POINTER_REGNUM
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+	   || x_regno == ARG_POINTER_REGNUM
+#endif
+	   || x_regno == FRAME_POINTER_REGNUM)
+	  && regno >= FIRST_VIRTUAL_REGISTER && regno <= LAST_VIRTUAL_REGISTER)
+	return 1;
+return endregno > x_regno && regno < END_REGNO (x);
+case SUBREG:
+/* If this is a SUBREG of a hard reg, we can see exactly which
+	 registers are being modified.  Otherwise, handle normally.  */
+if (REG_P (SUBREG_REG (x))
+	  && REGNO (SUBREG_REG (x)) < FIRST_PSEUDO_REGISTER)
+	{
+	  unsigned int inner_regno = subreg_regno (x);
+	  unsigned int inner_endregno
+	    = inner_regno + (inner_regno < FIRST_PSEUDO_REGISTER
+			     ? subreg_nregs (x) : 1);
+	  return endregno > inner_regno && regno < inner_endregno;
+	}
+break;
+case CLOBBER:
+case SET:
+if (&SET_DEST (x) != loc
+	  /* Note setting a SUBREG counts as referring to the REG it is in for
+	     a pseudo but not for hard registers since we can
+	     treat each word individually.  */
+	  && ((GET_CODE (SET_DEST (x)) == SUBREG
+	       && loc != &SUBREG_REG (SET_DEST (x))
+	       && REG_P (SUBREG_REG (SET_DEST (x)))
+	       && REGNO (SUBREG_REG (SET_DEST (x))) >= FIRST_PSEUDO_REGISTER
+	       && refers_to_regno_p (regno, endregno,
+				     SUBREG_REG (SET_DEST (x)), loc))
+	      || (!REG_P (SET_DEST (x))
+		  && refers_to_regno_p (regno, endregno, SET_DEST (x), loc))))
+	return 1;
+if (code == CLOBBER || loc == &SET_SRC (x))
+	return 0;
+x = SET_SRC (x);
+goto repeat;
+default:
+break;
+}
+/* X does not match, so try its subexpressions.  */
+fmt = GET_RTX_FORMAT (code);
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+{
+if (fmt[i] == 'e' && loc != &XEXP (x, i))
+	{
+	  if (i == 0)
+	    {
+	      x = XEXP (x, 0);
+	      goto repeat;
+	    }
+	  else
+	    if (refers_to_regno_p (regno, endregno, XEXP (x, i), loc))
+	      return 1;
+	}
+else if (fmt[i] == 'E')
+	{
+	  int j;
+	  for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+	    if (loc != &XVECEXP (x, i, j)
+		&& refers_to_regno_p (regno, endregno, XVECEXP (x, i, j), loc))
+	      return 1;
+	}
+}
+return 0;
+}
+/* Nonzero if modifying X will affect IN.  If X is a register or a SUBREG,
+we check if any register number in X conflicts with the relevant register
+numbers.  If X is a constant, return 0.  If X is a MEM, return 1 iff IN
+contains a MEM (we don't bother checking for memory addresses that can't
+conflict because we expect this to be a rare case.  */
+int
+reg_overlap_mentioned_p (const_rtx x, const_rtx in)
+{
+unsigned int regno, endregno;
+/* If either argument is a constant, then modifying X can not
+affect IN.  Here we look at IN, we can profitably combine
+CONSTANT_P (x) with the switch statement below.  */
+if (CONSTANT_P (in))
+return 0;
+recurse:
+switch (GET_CODE (x))
+{
+case STRICT_LOW_PART:
+case ZERO_EXTRACT:
+case SIGN_EXTRACT:
+/* Overly conservative.  */
+x = XEXP (x, 0);
+goto recurse;
+case SUBREG:
+regno = REGNO (SUBREG_REG (x));
+if (regno < FIRST_PSEUDO_REGISTER)
+	regno = subreg_regno (x);
+endregno = regno + (regno < FIRST_PSEUDO_REGISTER
+			  ? subreg_nregs (x) : 1);
+goto do_reg;
+case REG:
+regno = REGNO (x);
+endregno = END_REGNO (x);
+do_reg:
+return refers_to_regno_p (regno, endregno, in, (rtx*) 0);
+case MEM:
+{
+	const char *fmt;
+	int i;
+	if (MEM_P (in))
+	  return 1;
+	fmt = GET_RTX_FORMAT (GET_CODE (in));
+	for (i = GET_RTX_LENGTH (GET_CODE (in)) - 1; i >= 0; i--)
+	  if (fmt[i] == 'e')
+	    {
+	      if (reg_overlap_mentioned_p (x, XEXP (in, i)))
+		return 1;
+	    }
+	  else if (fmt[i] == 'E')
+	    {
+	      int j;
+	      for (j = XVECLEN (in, i) - 1; j >= 0; --j)
+		if (reg_overlap_mentioned_p (x, XVECEXP (in, i, j)))
+		  return 1;
+	    }
+	return 0;
+}
+case SCRATCH:
+case PC:
+case CC0:
+return reg_mentioned_p (x, in);
+case PARALLEL:
+{
+	int i;
+	/* If any register in here refers to it we return true.  */
+	for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
+	  if (XEXP (XVECEXP (x, 0, i), 0) != 0
+	      && reg_overlap_mentioned_p (XEXP (XVECEXP (x, 0, i), 0), in))
+	    return 1;
+	return 0;
+}
+default:
+gcc_assert (CONSTANT_P (x));
+return 0;
+}
+}
+/* Call FUN on each register or MEM that is stored into or clobbered by X.
+(X would be the pattern of an insn).  DATA is an arbitrary pointer,
+ignored by note_stores, but passed to FUN.
+FUN receives three arguments:
+1. the REG, MEM, CC0 or PC being stored in or clobbered,
+2. the SET or CLOBBER rtx that does the store,
+3. the pointer DATA provided to note_stores.
+If the item being stored in or clobbered is a SUBREG of a hard register,
+the SUBREG will be passed.  */
+void
+note_stores (const_rtx x, void (*fun) (rtx, const_rtx, void *), void *data)
+{
+int i;
+if (GET_CODE (x) == COND_EXEC)
+x = COND_EXEC_CODE (x);
+if (GET_CODE (x) == SET || GET_CODE (x) == CLOBBER)
+{
+rtx dest = SET_DEST (x);
+while ((GET_CODE (dest) == SUBREG
+	      && (!REG_P (SUBREG_REG (dest))
+		  || REGNO (SUBREG_REG (dest)) >= FIRST_PSEUDO_REGISTER))
+	     || GET_CODE (dest) == ZERO_EXTRACT
+	     || GET_CODE (dest) == STRICT_LOW_PART)
+	dest = XEXP (dest, 0);
+/* If we have a PARALLEL, SET_DEST is a list of EXPR_LIST expressions,
+	 each of whose first operand is a register.  */
+if (GET_CODE (dest) == PARALLEL)
+	{
+	  for (i = XVECLEN (dest, 0) - 1; i >= 0; i--)
+	    if (XEXP (XVECEXP (dest, 0, i), 0) != 0)
+	      (*fun) (XEXP (XVECEXP (dest, 0, i), 0), x, data);
+	}
+else
+	(*fun) (dest, x, data);
+}
+else if (GET_CODE (x) == PARALLEL)
+for (i = XVECLEN (x, 0) - 1; i >= 0; i--)
+note_stores (XVECEXP (x, 0, i), fun, data);
+}
+/* Like notes_stores, but call FUN for each expression that is being
+referenced in PBODY, a pointer to the PATTERN of an insn.  We only call
+FUN for each expression, not any interior subexpressions.  FUN receives a
+pointer to the expression and the DATA passed to this function.
+Note that this is not quite the same test as that done in reg_referenced_p
+since that considers something as being referenced if it is being
+partially set, while we do not.  */
+void
+note_uses (rtx *pbody, void (*fun) (rtx *, void *), void *data)
+{
+rtx body = *pbody;
+int i;
+switch (GET_CODE (body))
+{
+case COND_EXEC:
+(*fun) (&COND_EXEC_TEST (body), data);
+note_uses (&COND_EXEC_CODE (body), fun, data);
+return;
+case PARALLEL:
+for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
+	note_uses (&XVECEXP (body, 0, i), fun, data);
+return;
+case SEQUENCE:
+for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
+	note_uses (&PATTERN (XVECEXP (body, 0, i)), fun, data);
+return;
+case USE:
+(*fun) (&XEXP (body, 0), data);
+return;
+case ASM_OPERANDS:
+for (i = ASM_OPERANDS_INPUT_LENGTH (body) - 1; i >= 0; i--)
+	(*fun) (&ASM_OPERANDS_INPUT (body, i), data);
+return;
+case TRAP_IF:
+(*fun) (&TRAP_CONDITION (body), data);
+return;
+case PREFETCH:
+(*fun) (&XEXP (body, 0), data);
+return;
+case UNSPEC:
+case UNSPEC_VOLATILE:
+for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
+	(*fun) (&XVECEXP (body, 0, i), data);
+return;
+case CLOBBER:
+if (MEM_P (XEXP (body, 0)))
+	(*fun) (&XEXP (XEXP (body, 0), 0), data);
+return;
+case SET:
+{
+	rtx dest = SET_DEST (body);
+	/* For sets we replace everything in source plus registers in memory
+	   expression in store and operands of a ZERO_EXTRACT.  */
+	(*fun) (&SET_SRC (body), data);
+	if (GET_CODE (dest) == ZERO_EXTRACT)
+	  {
+	    (*fun) (&XEXP (dest, 1), data);
+	    (*fun) (&XEXP (dest, 2), data);
+	  }
+	while (GET_CODE (dest) == SUBREG || GET_CODE (dest) == STRICT_LOW_PART)
+	  dest = XEXP (dest, 0);
+	if (MEM_P (dest))
+	  (*fun) (&XEXP (dest, 0), data);
+}
+return;
+default:
+/* All the other possibilities never store.  */
+(*fun) (pbody, data);
+return;
+}
+}
+/* Return nonzero if X's old contents don't survive after INSN.
+This will be true if X is (cc0) or if X is a register and
+X dies in INSN or because INSN entirely sets X.
+"Entirely set" means set directly and not through a SUBREG, or
+ZERO_EXTRACT, so no trace of the old contents remains.
+Likewise, REG_INC does not count.
+REG may be a hard or pseudo reg.  Renumbering is not taken into account,
+but for this use that makes no difference, since regs don't overlap
+during their lifetimes.  Therefore, this function may be used
+at any time after deaths have been computed.
+If REG is a hard reg that occupies multiple machine registers, this
+function will only return 1 if each of those registers will be replaced
+by INSN.  */
+int
+dead_or_set_p (const_rtx insn, const_rtx x)
+{
+unsigned int regno, end_regno;
+unsigned int i;
+/* Can't use cc0_rtx below since this file is used by genattrtab.c.  */
+if (GET_CODE (x) == CC0)
+return 1;
+gcc_assert (REG_P (x));
+regno = REGNO (x);
+end_regno = END_REGNO (x);
+for (i = regno; i < end_regno; i++)
+if (! dead_or_set_regno_p (insn, i))
+return 0;
+return 1;
+}
+/* Return TRUE iff DEST is a register or subreg of a register and
+doesn't change the number of words of the inner register, and any
+part of the register is TEST_REGNO.  */
+static bool
+covers_regno_no_parallel_p (const_rtx dest, unsigned int test_regno)
+{
+unsigned int regno, endregno;
+if (GET_CODE (dest) == SUBREG
+&& (((GET_MODE_SIZE (GET_MODE (dest))
+	    + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
+	  == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest)))
+	       + UNITS_PER_WORD - 1) / UNITS_PER_WORD)))
+dest = SUBREG_REG (dest);
+if (!REG_P (dest))
+return false;
+regno = REGNO (dest);
+endregno = END_REGNO (dest);
+return (test_regno >= regno && test_regno < endregno);
+}
+/* Like covers_regno_no_parallel_p, but also handles PARALLELs where
+any member matches the covers_regno_no_parallel_p criteria.  */
+static bool
+covers_regno_p (const_rtx dest, unsigned int test_regno)
+{
+if (GET_CODE (dest) == PARALLEL)
+{
+/* Some targets place small structures in registers for return
+	 values of functions, and those registers are wrapped in
+	 PARALLELs that we may see as the destination of a SET.  */
+int i;
+for (i = XVECLEN (dest, 0) - 1; i >= 0; i--)
+	{
+	  rtx inner = XEXP (XVECEXP (dest, 0, i), 0);
+	  if (inner != NULL_RTX
+	      && covers_regno_no_parallel_p (inner, test_regno))
+	    return true;
+	}
+return false;
+}
+else
+return covers_regno_no_parallel_p (dest, test_regno);
+}
+/* Utility function for dead_or_set_p to check an individual register. */
+int
+dead_or_set_regno_p (const_rtx insn, unsigned int test_regno)
+{
+const_rtx pattern;
+/* See if there is a death note for something that includes TEST_REGNO.  */
+if (find_regno_note (insn, REG_DEAD, test_regno))
+return 1;
+if (CALL_P (insn)
+&& find_regno_fusage (insn, CLOBBER, test_regno))
+return 1;
+pattern = PATTERN (insn);
+if (GET_CODE (pattern) == COND_EXEC)
+pattern = COND_EXEC_CODE (pattern);
+if (GET_CODE (pattern) == SET)
+return covers_regno_p (SET_DEST (pattern), test_regno);
+else if (GET_CODE (pattern) == PARALLEL)
+{
+int i;
+for (i = XVECLEN (pattern, 0) - 1; i >= 0; i--)
+	{
+	  rtx body = XVECEXP (pattern, 0, i);
+	  if (GET_CODE (body) == COND_EXEC)
+	    body = COND_EXEC_CODE (body);
+	  if ((GET_CODE (body) == SET || GET_CODE (body) == CLOBBER)
+	      && covers_regno_p (SET_DEST (body), test_regno))
+	    return 1;
+	}
+}
+return 0;
+}
+/* Return the reg-note of kind KIND in insn INSN, if there is one.
+If DATUM is nonzero, look for one whose datum is DATUM.  */
+rtx
+find_reg_note (const_rtx insn, enum reg_note kind, const_rtx datum)
+{
+rtx link;
+gcc_assert (insn);
+/* Ignore anything that is not an INSN, JUMP_INSN or CALL_INSN.  */
+if (! INSN_P (insn))
+return 0;
+if (datum == 0)
+{
+for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
+	if (REG_NOTE_KIND (link) == kind)
+	  return link;
+return 0;
+}
+for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
+if (REG_NOTE_KIND (link) == kind && datum == XEXP (link, 0))
+return link;
+return 0;
+}
+/* Return the reg-note of kind KIND in insn INSN which applies to register
+number REGNO, if any.  Return 0 if there is no such reg-note.  Note that
+the REGNO of this NOTE need not be REGNO if REGNO is a hard register;
+it might be the case that the note overlaps REGNO.  */
+rtx
+find_regno_note (const_rtx insn, enum reg_note kind, unsigned int regno)
+{
+rtx link;
+/* Ignore anything that is not an INSN, JUMP_INSN or CALL_INSN.  */
+if (! INSN_P (insn))
+return 0;
+for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
+if (REG_NOTE_KIND (link) == kind
+	/* Verify that it is a register, so that scratch and MEM won't cause a
+	   problem here.  */
+	&& REG_P (XEXP (link, 0))
+	&& REGNO (XEXP (link, 0)) <= regno
+	&& END_REGNO (XEXP (link, 0)) > regno)
+return link;
+return 0;
+}
+/* Return a REG_EQUIV or REG_EQUAL note if insn has only a single set and
+has such a note.  */
+rtx
+find_reg_equal_equiv_note (const_rtx insn)
+{
+rtx link;
+if (!INSN_P (insn))
+return 0;
+for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
+if (REG_NOTE_KIND (link) == REG_EQUAL
+	|| REG_NOTE_KIND (link) == REG_EQUIV)
+{
+	/* FIXME: We should never have REG_EQUAL/REG_EQUIV notes on
+	   insns that have multiple sets.  Checking single_set to
+	   make sure of this is not the proper check, as explained
+	   in the comment in set_unique_reg_note.
+	   This should be changed into an assert.  */
+	if (GET_CODE (PATTERN (insn)) == PARALLEL && multiple_sets (insn))
+	  return 0;
+	return link;
+}
+return NULL;
+}
+/* Check whether INSN is a single_set whose source is known to be
+equivalent to a constant.  Return that constant if so, otherwise
+return null.  */
+rtx
+find_constant_src (const_rtx insn)
+{
+rtx note, set, x;
+set = single_set (insn);
+if (set)
+{
+x = avoid_constant_pool_reference (SET_SRC (set));
+if (CONSTANT_P (x))
+	return x;
+}
+note = find_reg_equal_equiv_note (insn);
+if (note && CONSTANT_P (XEXP (note, 0)))
+return XEXP (note, 0);
+return NULL_RTX;
+}
+/* Return true if DATUM, or any overlap of DATUM, of kind CODE is found
+in the CALL_INSN_FUNCTION_USAGE information of INSN.  */
+int
+find_reg_fusage (const_rtx insn, enum rtx_code code, const_rtx datum)
+{
+/* If it's not a CALL_INSN, it can't possibly have a
+CALL_INSN_FUNCTION_USAGE field, so don't bother checking.  */
+if (!CALL_P (insn))
+return 0;
+gcc_assert (datum);
+if (!REG_P (datum))
+{
+rtx link;
+for (link = CALL_INSN_FUNCTION_USAGE (insn);
+	   link;
+	   link = XEXP (link, 1))
+	if (GET_CODE (XEXP (link, 0)) == code
+	    && rtx_equal_p (datum, XEXP (XEXP (link, 0), 0)))
+	  return 1;
+}
+else
+{
+unsigned int regno = REGNO (datum);
+/* CALL_INSN_FUNCTION_USAGE information cannot contain references
+	 to pseudo registers, so don't bother checking.  */
+if (regno < FIRST_PSEUDO_REGISTER)
+	{
+	  unsigned int end_regno = END_HARD_REGNO (datum);
+	  unsigned int i;
+	  for (i = regno; i < end_regno; i++)
+	    if (find_regno_fusage (insn, code, i))
+	      return 1;
+	}
+}
+return 0;
+}
+/* Return true if REGNO, or any overlap of REGNO, of kind CODE is found
+in the CALL_INSN_FUNCTION_USAGE information of INSN.  */
+int
+find_regno_fusage (const_rtx insn, enum rtx_code code, unsigned int regno)
+{
+rtx link;
+/* CALL_INSN_FUNCTION_USAGE information cannot contain references
+to pseudo registers, so don't bother checking.  */
+if (regno >= FIRST_PSEUDO_REGISTER
+|| !CALL_P (insn) )
+return 0;
+for (link = CALL_INSN_FUNCTION_USAGE (insn); link; link = XEXP (link, 1))
+{
+rtx op, reg;
+if (GET_CODE (op = XEXP (link, 0)) == code
+	  && REG_P (reg = XEXP (op, 0))
+	  && REGNO (reg) <= regno
+	  && END_HARD_REGNO (reg) > regno)
+	return 1;
+}
+return 0;
+}
+/* Add register note with kind KIND and datum DATUM to INSN.  */
+void
+add_reg_note (rtx insn, enum reg_note kind, rtx datum)
+{
+rtx note;
+switch (kind)
+{
+case REG_CC_SETTER:
+case REG_CC_USER:
+case REG_LABEL_TARGET:
+case REG_LABEL_OPERAND:
+/* These types of register notes use an INSN_LIST rather than an
+	 EXPR_LIST, so that copying is done right and dumps look
+	 better.  */
+note = alloc_INSN_LIST (datum, REG_NOTES (insn));
+PUT_REG_NOTE_KIND (note, kind);
+break;
+default:
+note = alloc_EXPR_LIST (kind, datum, REG_NOTES (insn));
+break;
+}
+REG_NOTES (insn) = note;
+}
+/* Remove register note NOTE from the REG_NOTES of INSN.  */
+void
+remove_note (rtx insn, const_rtx note)
+{
+rtx link;
+if (note == NULL_RTX)
+return;
+if (REG_NOTES (insn) == note)
+REG_NOTES (insn) = XEXP (note, 1);
+else
+for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
+if (XEXP (link, 1) == note)
+	{
+	  XEXP (link, 1) = XEXP (note, 1);
+	  break;
+	}
+switch (REG_NOTE_KIND (note))
+{
+case REG_EQUAL:
+case REG_EQUIV:
+df_notes_rescan (insn);
+break;
+default:
+break;
+}
+}
+/* Remove REG_EQUAL and/or REG_EQUIV notes if INSN has such notes.  */
+void
+remove_reg_equal_equiv_notes (rtx insn)
+{
+rtx *loc;
+loc = &REG_NOTES (insn);
+while (*loc)
+{
+enum reg_note kind = REG_NOTE_KIND (*loc);
+if (kind == REG_EQUAL || kind == REG_EQUIV)
+	*loc = XEXP (*loc, 1);
+else
+	loc = &XEXP (*loc, 1);
+}
+}
+/* Search LISTP (an EXPR_LIST) for an entry whose first operand is NODE and
+return 1 if it is found.  A simple equality test is used to determine if
+NODE matches.  */
+int
+in_expr_list_p (const_rtx listp, const_rtx node)
+{
+const_rtx x;
+for (x = listp; x; x = XEXP (x, 1))
+if (node == XEXP (x, 0))
+return 1;
+return 0;
+}
+/* Search LISTP (an EXPR_LIST) for an entry whose first operand is NODE and
+remove that entry from the list if it is found.
+A simple equality test is used to determine if NODE matches.  */
+void
+remove_node_from_expr_list (const_rtx node, rtx *listp)
+{
+rtx temp = *listp;
+rtx prev = NULL_RTX;
+while (temp)
+{
+if (node == XEXP (temp, 0))
+	{
+	  /* Splice the node out of the list.  */
+	  if (prev)
+	    XEXP (prev, 1) = XEXP (temp, 1);
+	  else
+	    *listp = XEXP (temp, 1);
+	  return;
+	}
+prev = temp;
+temp = XEXP (temp, 1);
+}
+}
+/* Nonzero if X contains any volatile instructions.  These are instructions
+which may cause unpredictable machine state instructions, and thus no
+instructions should be moved or combined across them.  This includes
+only volatile asms and UNSPEC_VOLATILE instructions.  */
+int
+volatile_insn_p (const_rtx x)
+{
+const RTX_CODE code = GET_CODE (x);
+switch (code)
+{
+case LABEL_REF:
+case SYMBOL_REF:
+case CONST_INT:
+case CONST:
+case CONST_DOUBLE:
+case CONST_FIXED:
+case CONST_VECTOR:
+case CC0:
+case PC:
+case REG:
+case SCRATCH:
+case CLOBBER:
+case ADDR_VEC:
+case ADDR_DIFF_VEC:
+case CALL:
+case MEM:
+return 0;
+case UNSPEC_VOLATILE:
+/* case TRAP_IF: This isn't clear yet.  */
+return 1;
+case ASM_INPUT:
+case ASM_OPERANDS:
+if (MEM_VOLATILE_P (x))
+	return 1;
+default:
+break;
+}
+/* Recursively scan the operands of this expression.  */
+{
+const char *const fmt = GET_RTX_FORMAT (code);
+int i;
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+{
+	if (fmt[i] == 'e')
+	  {
+	    if (volatile_insn_p (XEXP (x, i)))
+	      return 1;
+	  }
+	else if (fmt[i] == 'E')
+	  {
+	    int j;
+	    for (j = 0; j < XVECLEN (x, i); j++)
+	      if (volatile_insn_p (XVECEXP (x, i, j)))
+		return 1;
+	  }
+}
+}
+return 0;
+}
+/* Nonzero if X contains any volatile memory references
+UNSPEC_VOLATILE operations or volatile ASM_OPERANDS expressions.  */
+int
+volatile_refs_p (const_rtx x)
+{
+const RTX_CODE code = GET_CODE (x);
+switch (code)
+{
+case LABEL_REF:
+case SYMBOL_REF:
+case CONST_INT:
+case CONST:
+case CONST_DOUBLE:
+case CONST_FIXED:
+case CONST_VECTOR:
+case CC0:
+case PC:
+case REG:
+case SCRATCH:
+case CLOBBER:
+case ADDR_VEC:
+case ADDR_DIFF_VEC:
+return 0;
+case UNSPEC_VOLATILE:
+return 1;
+case MEM:
+case ASM_INPUT:
+case ASM_OPERANDS:
+if (MEM_VOLATILE_P (x))
+	return 1;
+default:
+break;
+}
+/* Recursively scan the operands of this expression.  */
+{
+const char *const fmt = GET_RTX_FORMAT (code);
+int i;
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+{
+	if (fmt[i] == 'e')
+	  {
+	    if (volatile_refs_p (XEXP (x, i)))
+	      return 1;
+	  }
+	else if (fmt[i] == 'E')
+	  {
+	    int j;
+	    for (j = 0; j < XVECLEN (x, i); j++)
+	      if (volatile_refs_p (XVECEXP (x, i, j)))
+		return 1;
+	  }
+}
+}
+return 0;
+}
+/* Similar to above, except that it also rejects register pre- and post-
+incrementing.  */
+int
+side_effects_p (const_rtx x)
+{
+const RTX_CODE code = GET_CODE (x);
+switch (code)
+{
+case LABEL_REF:
+case SYMBOL_REF:
+case CONST_INT:
+case CONST:
+case CONST_DOUBLE:
+case CONST_FIXED:
+case CONST_VECTOR:
+case CC0:
+case PC:
+case REG:
+case SCRATCH:
+case ADDR_VEC:
+case ADDR_DIFF_VEC:
+return 0;
+case CLOBBER:
+/* Reject CLOBBER with a non-VOID mode.  These are made by combine.c
+	 when some combination can't be done.  If we see one, don't think
+	 that we can simplify the expression.  */
+return (GET_MODE (x) != VOIDmode);
+case PRE_INC:
+case PRE_DEC:
+case POST_INC:
+case POST_DEC:
+case PRE_MODIFY:
+case POST_MODIFY:
+case CALL:
+case UNSPEC_VOLATILE:
+/* case TRAP_IF: This isn't clear yet.  */
+return 1;
+case MEM:
+case ASM_INPUT:
+case ASM_OPERANDS:
+if (MEM_VOLATILE_P (x))
+	return 1;
+default:
+break;
+}
+/* Recursively scan the operands of this expression.  */
+{
+const char *fmt = GET_RTX_FORMAT (code);
+int i;
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+{
+	if (fmt[i] == 'e')
+	  {
+	    if (side_effects_p (XEXP (x, i)))
+	      return 1;
+	  }
+	else if (fmt[i] == 'E')
+	  {
+	    int j;
+	    for (j = 0; j < XVECLEN (x, i); j++)
+	      if (side_effects_p (XVECEXP (x, i, j)))
+		return 1;
+	  }
+}
+}
+return 0;
+}
+/* Return nonzero if evaluating rtx X might cause a trap.
+FLAGS controls how to consider MEMs.  A nonzero means the context
+of the access may have changed from the original, such that the
+address may have become invalid.  */
+int
+may_trap_p_1 (const_rtx x, unsigned flags)
+{
+int i;
+enum rtx_code code;
+const char *fmt;
+/* We make no distinction currently, but this function is part of
+the internal target-hooks ABI so we keep the parameter as
+"unsigned flags".  */
+bool code_changed = flags != 0;
+if (x == 0)
+return 0;
+code = GET_CODE (x);
+switch (code)
+{
+/* Handle these cases quickly.  */
+case CONST_INT:
+case CONST_DOUBLE:
+case CONST_FIXED:
+case CONST_VECTOR:
+case SYMBOL_REF:
+case LABEL_REF:
+case CONST:
+case PC:
+case CC0:
+case REG:
+case SCRATCH:
+return 0;
+case UNSPEC:
+case UNSPEC_VOLATILE:
+return targetm.unspec_may_trap_p (x, flags);
+case ASM_INPUT:
+case TRAP_IF:
+return 1;
+case ASM_OPERANDS:
+return MEM_VOLATILE_P (x);
+/* Memory ref can trap unless it's a static var or a stack slot.  */
+case MEM:
+if (/* MEM_NOTRAP_P only relates to the actual position of the memory
+	     reference; moving it out of context such as when moving code
+	     when optimizing, might cause its address to become invalid.  */
+	  code_changed
+	  || !MEM_NOTRAP_P (x))
+	{
+	  HOST_WIDE_INT size = MEM_SIZE (x) ? INTVAL (MEM_SIZE (x)) : 0;
+	  return rtx_addr_can_trap_p_1 (XEXP (x, 0), 0, size,
+					GET_MODE (x), code_changed);
+	}
+return 0;
+/* Division by a non-constant might trap.  */
+case DIV:
+case MOD:
+case UDIV:
+case UMOD:
+if (HONOR_SNANS (GET_MODE (x)))
+	return 1;
+if (SCALAR_FLOAT_MODE_P (GET_MODE (x)))
+	return flag_trapping_math;
+if (!CONSTANT_P (XEXP (x, 1)) || (XEXP (x, 1) == const0_rtx))
+	return 1;
+break;
+case EXPR_LIST:
+/* An EXPR_LIST is used to represent a function call.  This
+	 certainly may trap.  */
+return 1;
+case GE:
+case GT:
+case LE:
+case LT:
+case LTGT:
+case COMPARE:
+/* Some floating point comparisons may trap.  */
+if (!flag_trapping_math)
+	break;
+/* ??? There is no machine independent way to check for tests that trap
+	 when COMPARE is used, though many targets do make this distinction.
+	 For instance, sparc uses CCFPE for compares which generate exceptions
+	 and CCFP for compares which do not generate exceptions.  */
+if (HONOR_NANS (GET_MODE (x)))
+	return 1;
+/* But often the compare has some CC mode, so check operand
+	 modes as well.  */
+if (HONOR_NANS (GET_MODE (XEXP (x, 0)))
+	  || HONOR_NANS (GET_MODE (XEXP (x, 1))))
+	return 1;
+break;
+case EQ:
+case NE:
+if (HONOR_SNANS (GET_MODE (x)))
+	return 1;
+/* Often comparison is CC mode, so check operand modes.  */
+if (HONOR_SNANS (GET_MODE (XEXP (x, 0)))
+	  || HONOR_SNANS (GET_MODE (XEXP (x, 1))))
+	return 1;
+break;
+case FIX:
+/* Conversion of floating point might trap.  */
+if (flag_trapping_math && HONOR_NANS (GET_MODE (XEXP (x, 0))))
+	return 1;
+break;
+case NEG:
+case ABS:
+case SUBREG:
+/* These operations don't trap even with floating point.  */
+break;
+default:
+/* Any floating arithmetic may trap.  */
+if (SCALAR_FLOAT_MODE_P (GET_MODE (x))
+	  && flag_trapping_math)
+	return 1;
+}
+fmt = GET_RTX_FORMAT (code);
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+{
+if (fmt[i] == 'e')
+	{
+	  if (may_trap_p_1 (XEXP (x, i), flags))
+	    return 1;
+	}
+else if (fmt[i] == 'E')
+	{
+	  int j;
+	  for (j = 0; j < XVECLEN (x, i); j++)
+	    if (may_trap_p_1 (XVECEXP (x, i, j), flags))
+	      return 1;
+	}
+}
+return 0;
+}
+/* Return nonzero if evaluating rtx X might cause a trap.  */
+int
+may_trap_p (const_rtx x)
+{
+return may_trap_p_1 (x, 0);
+}
+/* Same as above, but additionally return nonzero if evaluating rtx X might
+cause a fault.  We define a fault for the purpose of this function as a
+erroneous execution condition that cannot be encountered during the normal
+execution of a valid program; the typical example is an unaligned memory
+access on a strict alignment machine.  The compiler guarantees that it
+doesn't generate code that will fault from a valid program, but this
+guarantee doesn't mean anything for individual instructions.  Consider
+the following example:
+struct S { int d; union { char *cp; int *ip; }; };
+int foo(struct S *s)
+{
+	if (s->d == 1)
+	  return *s->ip;
+	else
+	  return *s->cp;
+}
+on a strict alignment machine.  In a valid program, foo will never be
+invoked on a structure for which d is equal to 1 and the underlying
+unique field of the union not aligned on a 4-byte boundary, but the
+expression *s->ip might cause a fault if considered individually.
+At the RTL level, potentially problematic expressions will almost always
+verify may_trap_p; for example, the above dereference can be emitted as
+(mem:SI (reg:P)) and this expression is may_trap_p for a generic register.
+However, suppose that foo is inlined in a caller that causes s->cp to
+point to a local character variable and guarantees that s->d is not set
+to 1; foo may have been effectively translated into pseudo-RTL as:
+if ((reg:SI) == 1)
+	(set (reg:SI) (mem:SI (%fp - 7)))
+else
+	(set (reg:QI) (mem:QI (%fp - 7)))
+Now (mem:SI (%fp - 7)) is considered as not may_trap_p since it is a
+memory reference to a stack slot, but it will certainly cause a fault
+on a strict alignment machine.  */
+int
+may_trap_or_fault_p (const_rtx x)
+{
+return may_trap_p_1 (x, 1);
+}
+/* Return nonzero if X contains a comparison that is not either EQ or NE,
+i.e., an inequality.  */
+int
+inequality_comparisons_p (const_rtx x)
+{
+const char *fmt;
+int len, i;
+const enum rtx_code code = GET_CODE (x);
+switch (code)
+{
+case REG:
+case SCRATCH:
+case PC:
+case CC0:
+case CONST_INT:
+case CONST_DOUBLE:
+case CONST_FIXED:
+case CONST_VECTOR:
+case CONST:
+case LABEL_REF:
+case SYMBOL_REF:
+return 0;
+case LT:
+case LTU:
+case GT:
+case GTU:
+case LE:
+case LEU:
+case GE:
+case GEU:
+return 1;
+default:
+break;
+}
+len = GET_RTX_LENGTH (code);
+fmt = GET_RTX_FORMAT (code);
+for (i = 0; i < len; i++)
+{
+if (fmt[i] == 'e')
+	{
+	  if (inequality_comparisons_p (XEXP (x, i)))
+	    return 1;
+	}
+else if (fmt[i] == 'E')
+	{
+	  int j;
+	  for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+	    if (inequality_comparisons_p (XVECEXP (x, i, j)))
+	      return 1;
+	}
+}
+return 0;
+}
+/* Replace any occurrence of FROM in X with TO.  The function does
+not enter into CONST_DOUBLE for the replace.
+Note that copying is not done so X must not be shared unless all copies
+are to be modified.  */
+rtx
+replace_rtx (rtx x, rtx from, rtx to)
+{
+int i, j;
+const char *fmt;
+/* The following prevents loops occurrence when we change MEM in
+CONST_DOUBLE onto the same CONST_DOUBLE.  */
+if (x != 0 && GET_CODE (x) == CONST_DOUBLE)
+return x;
+if (x == from)
+return to;
+/* Allow this function to make replacements in EXPR_LISTs.  */
+if (x == 0)
+return 0;
+if (GET_CODE (x) == SUBREG)
+{
+rtx new_rtx = replace_rtx (SUBREG_REG (x), from, to);
+if (GET_CODE (new_rtx) == CONST_INT)
+	{
+	  x = simplify_subreg (GET_MODE (x), new_rtx,
+			       GET_MODE (SUBREG_REG (x)),
+			       SUBREG_BYTE (x));
+	  gcc_assert (x);
+	}
+else
+	SUBREG_REG (x) = new_rtx;
+return x;
+}
+else if (GET_CODE (x) == ZERO_EXTEND)
+{
+rtx new_rtx = replace_rtx (XEXP (x, 0), from, to);
+if (GET_CODE (new_rtx) == CONST_INT)
+	{
+	  x = simplify_unary_operation (ZERO_EXTEND, GET_MODE (x),
+					new_rtx, GET_MODE (XEXP (x, 0)));
+	  gcc_assert (x);
+	}
+else
+	XEXP (x, 0) = new_rtx;
+return x;
+}
+fmt = GET_RTX_FORMAT (GET_CODE (x));
+for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0; i--)
+{
+if (fmt[i] == 'e')
+	XEXP (x, i) = replace_rtx (XEXP (x, i), from, to);
+else if (fmt[i] == 'E')
+	for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+	  XVECEXP (x, i, j) = replace_rtx (XVECEXP (x, i, j), from, to);
+}
+return x;
+}
+/* Replace occurrences of the old label in *X with the new one.
+DATA is a REPLACE_LABEL_DATA containing the old and new labels.  */
+int
+replace_label (rtx *x, void *data)
+{
+rtx l = *x;
+rtx old_label = ((replace_label_data *) data)->r1;
+rtx new_label = ((replace_label_data *) data)->r2;
+bool update_label_nuses = ((replace_label_data *) data)->update_label_nuses;
+if (l == NULL_RTX)
+return 0;
+if (GET_CODE (l) == SYMBOL_REF
+&& CONSTANT_POOL_ADDRESS_P (l))
+{
+rtx c = get_pool_constant (l);
+if (rtx_referenced_p (old_label, c))
+	{
+	  rtx new_c, new_l;
+	  replace_label_data *d = (replace_label_data *) data;
+	  /* Create a copy of constant C; replace the label inside
+	     but do not update LABEL_NUSES because uses in constant pool
+	     are not counted.  */
+	  new_c = copy_rtx (c);
+	  d->update_label_nuses = false;
+	  for_each_rtx (&new_c, replace_label, data);
+	  d->update_label_nuses = update_label_nuses;
+	  /* Add the new constant NEW_C to constant pool and replace
+	     the old reference to constant by new reference.  */
+	  new_l = XEXP (force_const_mem (get_pool_mode (l), new_c), 0);
+	  *x = replace_rtx (l, l, new_l);
+	}
+return 0;
+}
+/* If this is a JUMP_INSN, then we also need to fix the JUMP_LABEL
+field.  This is not handled by for_each_rtx because it doesn't
+handle unprinted ('0') fields.  */
+if (JUMP_P (l) && JUMP_LABEL (l) == old_label)
+JUMP_LABEL (l) = new_label;
+if ((GET_CODE (l) == LABEL_REF
+|| GET_CODE (l) == INSN_LIST)
+&& XEXP (l, 0) == old_label)
+{
+XEXP (l, 0) = new_label;
+if (update_label_nuses)
+	{
+	  ++LABEL_NUSES (new_label);
+	  --LABEL_NUSES (old_label);
+	}
+return 0;
+}
+return 0;
+}
+/* When *BODY is equal to X or X is directly referenced by *BODY
+return nonzero, thus FOR_EACH_RTX stops traversing and returns nonzero
+too, otherwise FOR_EACH_RTX continues traversing *BODY.  */
+static int
+rtx_referenced_p_1 (rtx *body, void *x)
+{
+rtx y = (rtx) x;
+if (*body == NULL_RTX)
+return y == NULL_RTX;
+/* Return true if a label_ref *BODY refers to label Y.  */
+if (GET_CODE (*body) == LABEL_REF && LABEL_P (y))
+return XEXP (*body, 0) == y;
+/* If *BODY is a reference to pool constant traverse the constant.  */
+if (GET_CODE (*body) == SYMBOL_REF
+&& CONSTANT_POOL_ADDRESS_P (*body))
+return rtx_referenced_p (y, get_pool_constant (*body));
+/* By default, compare the RTL expressions.  */
+return rtx_equal_p (*body, y);
+}
+/* Return true if X is referenced in BODY.  */
+int
+rtx_referenced_p (rtx x, rtx body)
+{
+return for_each_rtx (&body, rtx_referenced_p_1, x);
+}
+/* If INSN is a tablejump return true and store the label (before jump table) to
+*LABELP and the jump table to *TABLEP.  LABELP and TABLEP may be NULL.  */
+bool
+tablejump_p (const_rtx insn, rtx *labelp, rtx *tablep)
+{
+rtx label, table;
+if (JUMP_P (insn)
+&& (label = JUMP_LABEL (insn)) != NULL_RTX
+&& (table = next_active_insn (label)) != NULL_RTX
+&& JUMP_P (table)
+&& (GET_CODE (PATTERN (table)) == ADDR_VEC
+	  || GET_CODE (PATTERN (table)) == ADDR_DIFF_VEC))
+{
+if (labelp)
+	*labelp = label;
+if (tablep)
+	*tablep = table;
+return true;
+}
+return false;
+}
+/* A subroutine of computed_jump_p, return 1 if X contains a REG or MEM or
+constant that is not in the constant pool and not in the condition
+of an IF_THEN_ELSE.  */
+static int
+computed_jump_p_1 (const_rtx x)
+{
+const enum rtx_code code = GET_CODE (x);
+int i, j;
+const char *fmt;
+switch (code)
+{
+case LABEL_REF:
+case PC:
+return 0;
+case CONST:
+case CONST_INT:
+case CONST_DOUBLE:
+case CONST_FIXED:
+case CONST_VECTOR:
+case SYMBOL_REF:
+case REG:
+return 1;
+case MEM:
+return ! (GET_CODE (XEXP (x, 0)) == SYMBOL_REF
+		&& CONSTANT_POOL_ADDRESS_P (XEXP (x, 0)));
+case IF_THEN_ELSE:
+return (computed_jump_p_1 (XEXP (x, 1))
+	      || computed_jump_p_1 (XEXP (x, 2)));
+default:
+break;
+}
+fmt = GET_RTX_FORMAT (code);
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+{
+if (fmt[i] == 'e'
+	  && computed_jump_p_1 (XEXP (x, i)))
+	return 1;
+else if (fmt[i] == 'E')
+	for (j = 0; j < XVECLEN (x, i); j++)
+	  if (computed_jump_p_1 (XVECEXP (x, i, j)))
+	    return 1;
+}
+return 0;
+}
+/* Return nonzero if INSN is an indirect jump (aka computed jump).
+Tablejumps and casesi insns are not considered indirect jumps;
+we can recognize them by a (use (label_ref)).  */
+int
+computed_jump_p (const_rtx insn)
+{
+int i;
+if (JUMP_P (insn))
+{
+rtx pat = PATTERN (insn);
+/* If we have a JUMP_LABEL set, we're not a computed jump.  */
+if (JUMP_LABEL (insn) != NULL)
+	return 0;
+if (GET_CODE (pat) == PARALLEL)
+	{
+	  int len = XVECLEN (pat, 0);
+	  int has_use_labelref = 0;
+	  for (i = len - 1; i >= 0; i--)
+	    if (GET_CODE (XVECEXP (pat, 0, i)) == USE
+		&& (GET_CODE (XEXP (XVECEXP (pat, 0, i), 0))
+		    == LABEL_REF))
+	      has_use_labelref = 1;
+	  if (! has_use_labelref)
+	    for (i = len - 1; i >= 0; i--)
+	      if (GET_CODE (XVECEXP (pat, 0, i)) == SET
+		  && SET_DEST (XVECEXP (pat, 0, i)) == pc_rtx
+		  && computed_jump_p_1 (SET_SRC (XVECEXP (pat, 0, i))))
+		return 1;
+	}
+else if (GET_CODE (pat) == SET
+	       && SET_DEST (pat) == pc_rtx
+	       && computed_jump_p_1 (SET_SRC (pat)))
+	return 1;
+}
+return 0;
+}
+/* Optimized loop of for_each_rtx, trying to avoid useless recursive
+calls.  Processes the subexpressions of EXP and passes them to F.  */
+static int
+for_each_rtx_1 (rtx exp, int n, rtx_function f, void *data)
+{
+int result, i, j;
+const char *format = GET_RTX_FORMAT (GET_CODE (exp));
+rtx *x;
+for (; format[n] != '\0'; n++)
+{
+switch (format[n])
+	{
+	case 'e':
+	  /* Call F on X.  */
+	  x = &XEXP (exp, n);
+	  result = (*f) (x, data);
+	  if (result == -1)
+	    /* Do not traverse sub-expressions.  */
+	    continue;
+	  else if (result != 0)
+	    /* Stop the traversal.  */
+	    return result;
+	  if (*x == NULL_RTX)
+	    /* There are no sub-expressions.  */
+	    continue;
+	  i = non_rtx_starting_operands[GET_CODE (*x)];
+	  if (i >= 0)
+	    {
+	      result = for_each_rtx_1 (*x, i, f, data);
+	      if (result != 0)
+		return result;
+	    }
+	  break;
+	case 'V':
+	case 'E':
+	  if (XVEC (exp, n) == 0)
+	    continue;
+	  for (j = 0; j < XVECLEN (exp, n); ++j)
+	    {
+	      /* Call F on X.  */
+	      x = &XVECEXP (exp, n, j);
+	      result = (*f) (x, data);
+	      if (result == -1)
+		/* Do not traverse sub-expressions.  */
+		continue;
+	      else if (result != 0)
+		/* Stop the traversal.  */
+		return result;
+	      if (*x == NULL_RTX)
+		/* There are no sub-expressions.  */
+		continue;
+	      i = non_rtx_starting_operands[GET_CODE (*x)];
+	      if (i >= 0)
+		{
+		  result = for_each_rtx_1 (*x, i, f, data);
+		  if (result != 0)
+		    return result;
+	        }
+	    }
+	  break;
+	default:
+	  /* Nothing to do.  */
+	  break;
+	}
+}
+return 0;
+}
+/* Traverse X via depth-first search, calling F for each
+sub-expression (including X itself).  F is also passed the DATA.
+If F returns -1, do not traverse sub-expressions, but continue
+traversing the rest of the tree.  If F ever returns any other
+nonzero value, stop the traversal, and return the value returned
+by F.  Otherwise, return 0.  This function does not traverse inside
+tree structure that contains RTX_EXPRs, or into sub-expressions
+whose format code is `0' since it is not known whether or not those
+codes are actually RTL.
+This routine is very general, and could (should?) be used to
+implement many of the other routines in this file.  */
+int
+for_each_rtx (rtx *x, rtx_function f, void *data)
+{
+int result;
+int i;
+/* Call F on X.  */
+result = (*f) (x, data);
+if (result == -1)
+/* Do not traverse sub-expressions.  */
+return 0;
+else if (result != 0)
+/* Stop the traversal.  */
+return result;
+if (*x == NULL_RTX)
+/* There are no sub-expressions.  */
+return 0;
+i = non_rtx_starting_operands[GET_CODE (*x)];
+if (i < 0)
+return 0;
+return for_each_rtx_1 (*x, i, f, data);
+}
+/* Searches X for any reference to REGNO, returning the rtx of the
+reference found if any.  Otherwise, returns NULL_RTX.  */
+rtx
+regno_use_in (unsigned int regno, rtx x)
+{
+const char *fmt;
+int i, j;
+rtx tem;
+if (REG_P (x) && REGNO (x) == regno)
+return x;
+fmt = GET_RTX_FORMAT (GET_CODE (x));
+for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0; i--)
+{
+if (fmt[i] == 'e')
+	{
+	  if ((tem = regno_use_in (regno, XEXP (x, i))))
+	    return tem;
+	}
+else if (fmt[i] == 'E')
+	for (j = XVECLEN (x, i) - 1; j >= 0; j--)
+	  if ((tem = regno_use_in (regno , XVECEXP (x, i, j))))
+	    return tem;
+}
+return NULL_RTX;
+}
+/* Return a value indicating whether OP, an operand of a commutative
+operation, is preferred as the first or second operand.  The higher
+the value, the stronger the preference for being the first operand.
+We use negative values to indicate a preference for the first operand
+and positive values for the second operand.  */
+int
+commutative_operand_precedence (rtx op)
+{
+enum rtx_code code = GET_CODE (op);
+/* Constants always come the second operand.  Prefer "nice" constants.  */
+if (code == CONST_INT)
+return -8;
+if (code == CONST_DOUBLE)
+return -7;
+if (code == CONST_FIXED)
+return -7;
+op = avoid_constant_pool_reference (op);
+code = GET_CODE (op);
+switch (GET_RTX_CLASS (code))
+{
+case RTX_CONST_OBJ:
+if (code == CONST_INT)
+return -6;
+if (code == CONST_DOUBLE)
+return -5;
+if (code == CONST_FIXED)
+return -5;
+return -4;
+case RTX_EXTRA:
+/* SUBREGs of objects should come second.  */
+if (code == SUBREG && OBJECT_P (SUBREG_REG (op)))
+return -3;
+return 0;
+case RTX_OBJ:
+/* Complex expressions should be the first, so decrease priority
+of objects.  Prefer pointer objects over non pointer objects.  */
+if ((REG_P (op) && REG_POINTER (op))
+	  || (MEM_P (op) && MEM_POINTER (op)))
+	return -1;
+return -2;
+case RTX_COMM_ARITH:
+/* Prefer operands that are themselves commutative to be first.
+This helps to make things linear.  In particular,
+(and (and (reg) (reg)) (not (reg))) is canonical.  */
+return 4;
+case RTX_BIN_ARITH:
+/* If only one operand is a binary expression, it will be the first
+operand.  In particular,  (plus (minus (reg) (reg)) (neg (reg)))
+is canonical, although it will usually be further simplified.  */
+return 2;
+case RTX_UNARY:
+/* Then prefer NEG and NOT.  */
+if (code == NEG || code == NOT)
+return 1;
+default:
+return 0;
+}
+}
+/* Return 1 iff it is necessary to swap operands of commutative operation
+in order to canonicalize expression.  */
+bool
+swap_commutative_operands_p (rtx x, rtx y)
+{
+return (commutative_operand_precedence (x)
+	  < commutative_operand_precedence (y));
+}
+/* Return 1 if X is an autoincrement side effect and the register is
+not the stack pointer.  */
+int
+auto_inc_p (const_rtx x)
+{
+switch (GET_CODE (x))
+{
+case PRE_INC:
+case POST_INC:
+case PRE_DEC:
+case POST_DEC:
+case PRE_MODIFY:
+case POST_MODIFY:
+/* There are no REG_INC notes for SP.  */
+if (XEXP (x, 0) != stack_pointer_rtx)
+	return 1;
+default:
+break;
+}
+return 0;
+}
+/* Return nonzero if IN contains a piece of rtl that has the address LOC.  */
+int
+loc_mentioned_in_p (rtx *loc, const_rtx in)
+{
+enum rtx_code code;
+const char *fmt;
+int i, j;
+if (!in)
+return 0;
+code = GET_CODE (in);
+fmt = GET_RTX_FORMAT (code);
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+{
+if (fmt[i] == 'e')
+	{
+	  if (loc == &XEXP (in, i) || loc_mentioned_in_p (loc, XEXP (in, i)))
+	    return 1;
+	}
+else if (fmt[i] == 'E')
+	for (j = XVECLEN (in, i) - 1; j >= 0; j--)
+	  if (loc == &XVECEXP (in, i, j)
+	      || loc_mentioned_in_p (loc, XVECEXP (in, i, j)))
+	    return 1;
+}
+return 0;
+}
+/* Helper function for subreg_lsb.  Given a subreg's OUTER_MODE, INNER_MODE,
+and SUBREG_BYTE, return the bit offset where the subreg begins
+(counting from the least significant bit of the operand).  */
+unsigned int
+subreg_lsb_1 (enum machine_mode outer_mode,
+	      enum machine_mode inner_mode,
+	      unsigned int subreg_byte)
+{
+unsigned int bitpos;
+unsigned int byte;
+unsigned int word;
+/* A paradoxical subreg begins at bit position 0.  */
+if (GET_MODE_BITSIZE (outer_mode) > GET_MODE_BITSIZE (inner_mode))
+return 0;
+if (WORDS_BIG_ENDIAN != BYTES_BIG_ENDIAN)
+/* If the subreg crosses a word boundary ensure that
+it also begins and ends on a word boundary.  */
+gcc_assert (!((subreg_byte % UNITS_PER_WORD
+		  + GET_MODE_SIZE (outer_mode)) > UNITS_PER_WORD
+		  && (subreg_byte % UNITS_PER_WORD
+		      || GET_MODE_SIZE (outer_mode) % UNITS_PER_WORD)));
+if (WORDS_BIG_ENDIAN)
+word = (GET_MODE_SIZE (inner_mode)
+	    - (subreg_byte + GET_MODE_SIZE (outer_mode))) / UNITS_PER_WORD;
+else
+word = subreg_byte / UNITS_PER_WORD;
+bitpos = word * BITS_PER_WORD;
+if (BYTES_BIG_ENDIAN)
+byte = (GET_MODE_SIZE (inner_mode)
+	    - (subreg_byte + GET_MODE_SIZE (outer_mode))) % UNITS_PER_WORD;
+else
+byte = subreg_byte % UNITS_PER_WORD;
+bitpos += byte * BITS_PER_UNIT;
+return bitpos;
+}
+/* Given a subreg X, return the bit offset where the subreg begins
+(counting from the least significant bit of the reg).  */
+unsigned int
+subreg_lsb (const_rtx x)
+{
+return subreg_lsb_1 (GET_MODE (x), GET_MODE (SUBREG_REG (x)),
+		       SUBREG_BYTE (x));
+}
+/* Fill in information about a subreg of a hard register.
+xregno - A regno of an inner hard subreg_reg (or what will become one).
+xmode  - The mode of xregno.
+offset - The byte offset.
+ymode  - The mode of a top level SUBREG (or what may become one).
+info   - Pointer to structure to fill in.  */
+static void
+subreg_get_info (unsigned int xregno, enum machine_mode xmode,
+		 unsigned int offset, enum machine_mode ymode,
+		 struct subreg_info *info)
+{
+int nregs_xmode, nregs_ymode;
+int mode_multiple, nregs_multiple;
+int offset_adj, y_offset, y_offset_adj;
+int regsize_xmode, regsize_ymode;
+bool rknown;
+gcc_assert (xregno < FIRST_PSEUDO_REGISTER);
+rknown = false;
+/* If there are holes in a non-scalar mode in registers, we expect
+that it is made up of its units concatenated together.  */
+if (HARD_REGNO_NREGS_HAS_PADDING (xregno, xmode))
+{
+enum machine_mode xmode_unit;
+nregs_xmode = HARD_REGNO_NREGS_WITH_PADDING (xregno, xmode);
+if (GET_MODE_INNER (xmode) == VOIDmode)
+	xmode_unit = xmode;
+else
+	xmode_unit = GET_MODE_INNER (xmode);
+gcc_assert (HARD_REGNO_NREGS_HAS_PADDING (xregno, xmode_unit));
+gcc_assert (nregs_xmode
+		  == (GET_MODE_NUNITS (xmode)
+		      * HARD_REGNO_NREGS_WITH_PADDING (xregno, xmode_unit)));
+gcc_assert (hard_regno_nregs[xregno][xmode]
+		  == (hard_regno_nregs[xregno][xmode_unit]
+		      * GET_MODE_NUNITS (xmode)));
+/* You can only ask for a SUBREG of a value with holes in the middle
+	 if you don't cross the holes.  (Such a SUBREG should be done by
+	 picking a different register class, or doing it in memory if
+	 necessary.)  An example of a value with holes is XCmode on 32-bit
+	 x86 with -m128bit-long-double; it's represented in 6 32-bit registers,
+	 3 for each part, but in memory it's two 128-bit parts.
+	 Padding is assumed to be at the end (not necessarily the 'high part')
+	 of each unit.  */
+if ((offset / GET_MODE_SIZE (xmode_unit) + 1
+	   < GET_MODE_NUNITS (xmode))
+	  && (offset / GET_MODE_SIZE (xmode_unit)
+	      != ((offset + GET_MODE_SIZE (ymode) - 1)
+		  / GET_MODE_SIZE (xmode_unit))))
+	{
+	  info->representable_p = false;
+	  rknown = true;
+	}
+}
+else
+nregs_xmode = hard_regno_nregs[xregno][xmode];
+nregs_ymode = hard_regno_nregs[xregno][ymode];
+/* Paradoxical subregs are otherwise valid.  */
+if (!rknown
+&& offset == 0
+&& GET_MODE_SIZE (ymode) > GET_MODE_SIZE (xmode))
+{
+info->representable_p = true;
+/* If this is a big endian paradoxical subreg, which uses more
+	 actual hard registers than the original register, we must
+	 return a negative offset so that we find the proper highpart
+	 of the register.  */
+if (GET_MODE_SIZE (ymode) > UNITS_PER_WORD
+	  ? WORDS_BIG_ENDIAN : BYTES_BIG_ENDIAN)
+	info->offset = nregs_xmode - nregs_ymode;
+else
+	info->offset = 0;
+info->nregs = nregs_ymode;
+return;
+}
+/* If registers store different numbers of bits in the different
+modes, we cannot generally form this subreg.  */
+if (!HARD_REGNO_NREGS_HAS_PADDING (xregno, xmode)
+&& !HARD_REGNO_NREGS_HAS_PADDING (xregno, ymode)
+&& (GET_MODE_SIZE (xmode) % nregs_xmode) == 0
+&& (GET_MODE_SIZE (ymode) % nregs_ymode) == 0)
+{
+regsize_xmode = GET_MODE_SIZE (xmode) / nregs_xmode;
+regsize_ymode = GET_MODE_SIZE (ymode) / nregs_ymode;
+if (!rknown && regsize_xmode > regsize_ymode && nregs_ymode > 1)
+	{
+	  info->representable_p = false;
+	  info->nregs
+	    = (GET_MODE_SIZE (ymode) + regsize_xmode - 1) / regsize_xmode;
+	  info->offset = offset / regsize_xmode;
+	  return;
+	}
+if (!rknown && regsize_ymode > regsize_xmode && nregs_xmode > 1)
+	{
+	  info->representable_p = false;
+	  info->nregs
+	    = (GET_MODE_SIZE (ymode) + regsize_xmode - 1) / regsize_xmode;
+	  info->offset = offset / regsize_xmode;
+	  return;
+	}
+}
+/* Lowpart subregs are otherwise valid.  */
+if (!rknown && offset == subreg_lowpart_offset (ymode, xmode))
+{
+info->representable_p = true;
+rknown = true;
+if (offset == 0 || nregs_xmode == nregs_ymode)
+	{
+	  info->offset = 0;
+	  info->nregs = nregs_ymode;
+	  return;
+	}
+}
+/* This should always pass, otherwise we don't know how to verify
+the constraint.  These conditions may be relaxed but
+subreg_regno_offset would need to be redesigned.  */
+gcc_assert ((GET_MODE_SIZE (xmode) % GET_MODE_SIZE (ymode)) == 0);
+gcc_assert ((nregs_xmode % nregs_ymode) == 0);
+/* The XMODE value can be seen as a vector of NREGS_XMODE
+values.  The subreg must represent a lowpart of given field.
+Compute what field it is.  */
+offset_adj = offset;
+offset_adj -= subreg_lowpart_offset (ymode,
+				       mode_for_size (GET_MODE_BITSIZE (xmode)
+						      / nregs_xmode,
+						      MODE_INT, 0));
+/* Size of ymode must not be greater than the size of xmode.  */
+mode_multiple = GET_MODE_SIZE (xmode) / GET_MODE_SIZE (ymode);
+gcc_assert (mode_multiple != 0);
+y_offset = offset / GET_MODE_SIZE (ymode);
+y_offset_adj = offset_adj / GET_MODE_SIZE (ymode);
+nregs_multiple = nregs_xmode / nregs_ymode;
+gcc_assert ((offset_adj % GET_MODE_SIZE (ymode)) == 0);
+gcc_assert ((mode_multiple % nregs_multiple) == 0);
+if (!rknown)
+{
+info->representable_p = (!(y_offset_adj % (mode_multiple / nregs_multiple)));
+rknown = true;
+}
+info->offset = (y_offset / (mode_multiple / nregs_multiple)) * nregs_ymode;
+info->nregs = nregs_ymode;
+}
+/* This function returns the regno offset of a subreg expression.
+xregno - A regno of an inner hard subreg_reg (or what will become one).
+xmode  - The mode of xregno.
+offset - The byte offset.
+ymode  - The mode of a top level SUBREG (or what may become one).
+RETURN - The regno offset which would be used.  */
+unsigned int
+subreg_regno_offset (unsigned int xregno, enum machine_mode xmode,
+		     unsigned int offset, enum machine_mode ymode)
+{
+struct subreg_info info;
+subreg_get_info (xregno, xmode, offset, ymode, &info);
+return info.offset;
+}
+/* This function returns true when the offset is representable via
+subreg_offset in the given regno.
+xregno - A regno of an inner hard subreg_reg (or what will become one).
+xmode  - The mode of xregno.
+offset - The byte offset.
+ymode  - The mode of a top level SUBREG (or what may become one).
+RETURN - Whether the offset is representable.  */
+bool
+subreg_offset_representable_p (unsigned int xregno, enum machine_mode xmode,
+			       unsigned int offset, enum machine_mode ymode)
+{
+struct subreg_info info;
+subreg_get_info (xregno, xmode, offset, ymode, &info);
+return info.representable_p;
+}
+/* Return the number of a YMODE register to which
+(subreg:YMODE (reg:XMODE XREGNO) OFFSET)
+can be simplified.  Return -1 if the subreg can't be simplified.
+XREGNO is a hard register number.  */
+int
+simplify_subreg_regno (unsigned int xregno, enum machine_mode xmode,
+		       unsigned int offset, enum machine_mode ymode)
+{
+struct subreg_info info;
+unsigned int yregno;
+#ifdef CANNOT_CHANGE_MODE_CLASS
+/* Give the backend a chance to disallow the mode change.  */
+if (GET_MODE_CLASS (xmode) != MODE_COMPLEX_INT
+&& GET_MODE_CLASS (xmode) != MODE_COMPLEX_FLOAT
+&& REG_CANNOT_CHANGE_MODE_P (xregno, xmode, ymode))
+return -1;
+#endif
+/* We shouldn't simplify stack-related registers.  */
+if ((!reload_completed || frame_pointer_needed)
+&& (xregno == FRAME_POINTER_REGNUM
+	  || xregno == HARD_FRAME_POINTER_REGNUM))
+return -1;
+if (FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+&& xregno == ARG_POINTER_REGNUM)
+return -1;
+if (xregno == STACK_POINTER_REGNUM)
+return -1;
+/* Try to get the register offset.  */
+subreg_get_info (xregno, xmode, offset, ymode, &info);
+if (!info.representable_p)
+return -1;
+/* Make sure that the offsetted register value is in range.  */
+yregno = xregno + info.offset;
+if (!HARD_REGISTER_NUM_P (yregno))
+return -1;
+/* See whether (reg:YMODE YREGNO) is valid.
+??? We allow invalid registers if (reg:XMODE XREGNO) is also invalid.
+This is a kludge to work around how float/complex arguments are passed
+on 32-bit SPARC and should be fixed.  */
+if (!HARD_REGNO_MODE_OK (yregno, ymode)
+&& HARD_REGNO_MODE_OK (xregno, xmode))
+return -1;
+return (int) yregno;
+}
+/* Return the final regno that a subreg expression refers to.  */
+unsigned int
+subreg_regno (const_rtx x)
+{
+unsigned int ret;
+rtx subreg = SUBREG_REG (x);
+int regno = REGNO (subreg);
+ret = regno + subreg_regno_offset (regno,
+				     GET_MODE (subreg),
+				     SUBREG_BYTE (x),
+				     GET_MODE (x));
+return ret;
+}
+/* Return the number of registers that a subreg expression refers
+to.  */
+unsigned int
+subreg_nregs (const_rtx x)
+{
+return subreg_nregs_with_regno (REGNO (SUBREG_REG (x)), x);
+}
+/* Return the number of registers that a subreg REG with REGNO
+expression refers to.  This is a copy of the rtlanal.c:subreg_nregs
+changed so that the regno can be passed in. */
+unsigned int
+subreg_nregs_with_regno (unsigned int regno, const_rtx x)
+{
+struct subreg_info info;
+rtx subreg = SUBREG_REG (x);
+subreg_get_info (regno, GET_MODE (subreg), SUBREG_BYTE (x), GET_MODE (x),
+		   &info);
+return info.nregs;
+}
+struct parms_set_data
+{
+int nregs;
+HARD_REG_SET regs;
+};
+/* Helper function for noticing stores to parameter registers.  */
+static void
+parms_set (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data)
+{
+struct parms_set_data *const d = (struct parms_set_data *) data;
+if (REG_P (x) && REGNO (x) < FIRST_PSEUDO_REGISTER
+&& TEST_HARD_REG_BIT (d->regs, REGNO (x)))
+{
+CLEAR_HARD_REG_BIT (d->regs, REGNO (x));
+d->nregs--;
+}
+}
+/* Look backward for first parameter to be loaded.
+Note that loads of all parameters will not necessarily be
+found if CSE has eliminated some of them (e.g., an argument
+to the outer function is passed down as a parameter).
+Do not skip BOUNDARY.  */
+rtx
+find_first_parameter_load (rtx call_insn, rtx boundary)
+{
+struct parms_set_data parm;
+rtx p, before, first_set;
+/* Since different machines initialize their parameter registers
+in different orders, assume nothing.  Collect the set of all
+parameter registers.  */
+CLEAR_HARD_REG_SET (parm.regs);
+parm.nregs = 0;
+for (p = CALL_INSN_FUNCTION_USAGE (call_insn); p; p = XEXP (p, 1))
+if (GET_CODE (XEXP (p, 0)) == USE
+	&& REG_P (XEXP (XEXP (p, 0), 0)))
+{
+	gcc_assert (REGNO (XEXP (XEXP (p, 0), 0)) < FIRST_PSEUDO_REGISTER);
+	/* We only care about registers which can hold function
+	   arguments.  */
+	if (!FUNCTION_ARG_REGNO_P (REGNO (XEXP (XEXP (p, 0), 0))))
+	  continue;
+	SET_HARD_REG_BIT (parm.regs, REGNO (XEXP (XEXP (p, 0), 0)));
+	parm.nregs++;
+}
+before = call_insn;
+first_set = call_insn;
+/* Search backward for the first set of a register in this set.  */
+while (parm.nregs && before != boundary)
+{
+before = PREV_INSN (before);
+/* It is possible that some loads got CSEed from one call to
+another.  Stop in that case.  */
+if (CALL_P (before))
+	break;
+/* Our caller needs either ensure that we will find all sets
+(in case code has not been optimized yet), or take care
+for possible labels in a way by setting boundary to preceding
+CODE_LABEL.  */
+if (LABEL_P (before))
+	{
+	  gcc_assert (before == boundary);
+	  break;
+	}
+if (INSN_P (before))
+	{
+	  int nregs_old = parm.nregs;
+	  note_stores (PATTERN (before), parms_set, &parm);
+	  /* If we found something that did not set a parameter reg,
+	     we're done.  Do not keep going, as that might result
+	     in hoisting an insn before the setting of a pseudo
+	     that is used by the hoisted insn. */
+	  if (nregs_old != parm.nregs)
+	    first_set = before;
+	  else
+	    break;
+	}
+}
+return first_set;
+}
+/* Return true if we should avoid inserting code between INSN and preceding
+call instruction.  */
+bool
+keep_with_call_p (const_rtx insn)
+{
+rtx set;
+if (INSN_P (insn) && (set = single_set (insn)) != NULL)
+{
+if (REG_P (SET_DEST (set))
+	  && REGNO (SET_DEST (set)) < FIRST_PSEUDO_REGISTER
+	  && fixed_regs[REGNO (SET_DEST (set))]
+	  && general_operand (SET_SRC (set), VOIDmode))
+	return true;
+if (REG_P (SET_SRC (set))
+	  && FUNCTION_VALUE_REGNO_P (REGNO (SET_SRC (set)))
+	  && REG_P (SET_DEST (set))
+	  && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER)
+	return true;
+/* There may be a stack pop just after the call and before the store
+	 of the return register.  Search for the actual store when deciding
+	 if we can break or not.  */
+if (SET_DEST (set) == stack_pointer_rtx)
+	{
+	  /* This CONST_CAST is okay because next_nonnote_insn just
+	     returns its argument and we assign it to a const_rtx
+	     variable.  */
+	  const_rtx i2 = next_nonnote_insn (CONST_CAST_RTX(insn));
+	  if (i2 && keep_with_call_p (i2))
+	    return true;
+	}
+}
+return false;
+}
+/* Return true if LABEL is a target of JUMP_INSN.  This applies only
+to non-complex jumps.  That is, direct unconditional, conditional,
+and tablejumps, but not computed jumps or returns.  It also does
+not apply to the fallthru case of a conditional jump.  */
+bool
+label_is_jump_target_p (const_rtx label, const_rtx jump_insn)
+{
+rtx tmp = JUMP_LABEL (jump_insn);
+if (label == tmp)
+return true;
+if (tablejump_p (jump_insn, NULL, &tmp))
+{
+rtvec vec = XVEC (PATTERN (tmp),
+			GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC);
+int i, veclen = GET_NUM_ELEM (vec);
+for (i = 0; i < veclen; ++i)
+	if (XEXP (RTVEC_ELT (vec, i), 0) == label)
+	  return true;
+}
+if (find_reg_note (jump_insn, REG_LABEL_TARGET, label))
+return true;
+return false;
+}
+/* Return an estimate of the cost of computing rtx X.
+One use is in cse, to decide which expression to keep in the hash table.
+Another is in rtl generation, to pick the cheapest way to multiply.
+Other uses like the latter are expected in the future.
+SPEED parameter specify whether costs optimized for speed or size should
+be returned.  */
+int
+rtx_cost (rtx x, enum rtx_code outer_code ATTRIBUTE_UNUSED, bool speed)
+{
+int i, j;
+enum rtx_code code;
+const char *fmt;
+int total;
+if (x == 0)
+return 0;
+/* Compute the default costs of certain things.
+Note that targetm.rtx_costs can override the defaults.  */
+code = GET_CODE (x);
+switch (code)
+{
+case MULT:
+total = COSTS_N_INSNS (5);
+break;
+case DIV:
+case UDIV:
+case MOD:
+case UMOD:
+total = COSTS_N_INSNS (7);
+break;
+case USE:
+/* Used in combine.c as a marker.  */
+total = 0;
+break;
+default:
+total = COSTS_N_INSNS (1);
+}
+switch (code)
+{
+case REG:
+return 0;
+case SUBREG:
+total = 0;
+/* If we can't tie these modes, make this expensive.  The larger
+	 the mode, the more expensive it is.  */
+if (! MODES_TIEABLE_P (GET_MODE (x), GET_MODE (SUBREG_REG (x))))
+	return COSTS_N_INSNS (2
+			      + GET_MODE_SIZE (GET_MODE (x)) / UNITS_PER_WORD);
+break;
+default:
+if (targetm.rtx_costs (x, code, outer_code, &total, speed))
+	return total;
+break;
+}
+/* Sum the costs of the sub-rtx's, plus cost of this operation,
+which is already in total.  */
+fmt = GET_RTX_FORMAT (code);
+for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+if (fmt[i] == 'e')
+total += rtx_cost (XEXP (x, i), code, speed);
+else if (fmt[i] == 'E')
+for (j = 0; j < XVECLEN (x, i); j++)
+	total += rtx_cost (XVECEXP (x, i, j), code, speed);
+return total;
+}
+/* Return cost of address expression X.
+Expect that X is properly formed address reference.
+SPEED parameter specify whether costs optimized for speed or size should
+be returned.  */
+int
+address_cost (rtx x, enum machine_mode mode, bool speed)
+{
+/* We may be asked for cost of various unusual addresses, such as operands
+of push instruction.  It is not worthwhile to complicate writing
+of the target hook by such cases.  */
+if (!memory_address_p (mode, x))
+return 1000;
+return targetm.address_cost (x, speed);
+}
+/* If the target doesn't override, compute the cost as with arithmetic.  */
+int
+default_address_cost (rtx x, bool speed)
+{
+return rtx_cost (x, MEM, speed);
+}
+unsigned HOST_WIDE_INT
+nonzero_bits (const_rtx x, enum machine_mode mode)
+{
+return cached_nonzero_bits (x, mode, NULL_RTX, VOIDmode, 0);
+}
+unsigned int
+num_sign_bit_copies (const_rtx x, enum machine_mode mode)
+{
+return cached_num_sign_bit_copies (x, mode, NULL_RTX, VOIDmode, 0);
+}
+/* The function cached_nonzero_bits is a wrapper around nonzero_bits1.
+It avoids exponential behavior in nonzero_bits1 when X has
+identical subexpressions on the first or the second level.  */
+static unsigned HOST_WIDE_INT
+cached_nonzero_bits (const_rtx x, enum machine_mode mode, const_rtx known_x,
+		     enum machine_mode known_mode,
+		     unsigned HOST_WIDE_INT known_ret)
+{
+if (x == known_x && mode == known_mode)
+return known_ret;
+/* Try to find identical subexpressions.  If found call
+nonzero_bits1 on X with the subexpressions as KNOWN_X and the
+precomputed value for the subexpression as KNOWN_RET.  */
+if (ARITHMETIC_P (x))
+{
+rtx x0 = XEXP (x, 0);
+rtx x1 = XEXP (x, 1);
+/* Check the first level.  */
+if (x0 == x1)
+	return nonzero_bits1 (x, mode, x0, mode,
+			      cached_nonzero_bits (x0, mode, known_x,
+						   known_mode, known_ret));
+/* Check the second level.  */
+if (ARITHMETIC_P (x0)
+	  && (x1 == XEXP (x0, 0) || x1 == XEXP (x0, 1)))
+	return nonzero_bits1 (x, mode, x1, mode,
+			      cached_nonzero_bits (x1, mode, known_x,
+						   known_mode, known_ret));
+if (ARITHMETIC_P (x1)
+	  && (x0 == XEXP (x1, 0) || x0 == XEXP (x1, 1)))
+	return nonzero_bits1 (x, mode, x0, mode,
+			      cached_nonzero_bits (x0, mode, known_x,
+						   known_mode, known_ret));
+}
+return nonzero_bits1 (x, mode, known_x, known_mode, known_ret);
+}
+/* We let num_sign_bit_copies recur into nonzero_bits as that is useful.
+We don't let nonzero_bits recur into num_sign_bit_copies, because that
+is less useful.  We can't allow both, because that results in exponential
+run time recursion.  There is a nullstone testcase that triggered
+this.  This macro avoids accidental uses of num_sign_bit_copies.  */
+#define cached_num_sign_bit_copies sorry_i_am_preventing_exponential_behavior
+/* Given an expression, X, compute which bits in X can be nonzero.
+We don't care about bits outside of those defined in MODE.
+For most X this is simply GET_MODE_MASK (GET_MODE (MODE)), but if X is
+an arithmetic operation, we can do better.  */
+static unsigned HOST_WIDE_INT
+nonzero_bits1 (const_rtx x, enum machine_mode mode, const_rtx known_x,
+	       enum machine_mode known_mode,
+	       unsigned HOST_WIDE_INT known_ret)
+{
+unsigned HOST_WIDE_INT nonzero = GET_MODE_MASK (mode);
+unsigned HOST_WIDE_INT inner_nz;
+enum rtx_code code;
+unsigned int mode_width = GET_MODE_BITSIZE (mode);
+/* For floating-point and vector values, assume all bits are needed.  */
+if (FLOAT_MODE_P (GET_MODE (x)) || FLOAT_MODE_P (mode)
+|| VECTOR_MODE_P (GET_MODE (x)) || VECTOR_MODE_P (mode))
+return nonzero;
+/* If X is wider than MODE, use its mode instead.  */
+if (GET_MODE_BITSIZE (GET_MODE (x)) > mode_width)
+{
+mode = GET_MODE (x);
+nonzero = GET_MODE_MASK (mode);
+mode_width = GET_MODE_BITSIZE (mode);
+}
+if (mode_width > HOST_BITS_PER_WIDE_INT)
+/* Our only callers in this case look for single bit values.  So
+just return the mode mask.  Those tests will then be false.  */
+return nonzero;
+#ifndef WORD_REGISTER_OPERATIONS
+/* If MODE is wider than X, but both are a single word for both the host
+and target machines, we can compute this from which bits of the
+object might be nonzero in its own mode, taking into account the fact
+that on many CISC machines, accessing an object in a wider mode
+causes the high-order bits to become undefined.  So they are
+not known to be zero.  */
+if (GET_MODE (x) != VOIDmode && GET_MODE (x) != mode
+&& GET_MODE_BITSIZE (GET_MODE (x)) <= BITS_PER_WORD
+&& GET_MODE_BITSIZE (GET_MODE (x)) <= HOST_BITS_PER_WIDE_INT
+&& GET_MODE_BITSIZE (mode) > GET_MODE_BITSIZE (GET_MODE (x)))
+{
+nonzero &= cached_nonzero_bits (x, GET_MODE (x),
+				      known_x, known_mode, known_ret);
+nonzero |= GET_MODE_MASK (mode) & ~GET_MODE_MASK (GET_MODE (x));
+return nonzero;
+}
+#endif
+code = GET_CODE (x);
+switch (code)
+{
+case REG:
+#if defined(POINTERS_EXTEND_UNSIGNED) && !defined(HAVE_ptr_extend)
+/* If pointers extend unsigned and this is a pointer in Pmode, say that
+	 all the bits above ptr_mode are known to be zero.  */
+if (POINTERS_EXTEND_UNSIGNED && GET_MODE (x) == Pmode
+	  && REG_POINTER (x))
+	nonzero &= GET_MODE_MASK (ptr_mode);
+#endif
+/* Include declared information about alignment of pointers.  */
+/* ??? We don't properly preserve REG_POINTER changes across
+	 pointer-to-integer casts, so we can't trust it except for
+	 things that we know must be pointers.  See execute/960116-1.c.  */
+if ((x == stack_pointer_rtx
+	   || x == frame_pointer_rtx
+	   || x == arg_pointer_rtx)
+	  && REGNO_POINTER_ALIGN (REGNO (x)))
+	{
+	  unsigned HOST_WIDE_INT alignment
+	    = REGNO_POINTER_ALIGN (REGNO (x)) / BITS_PER_UNIT;
+#ifdef PUSH_ROUNDING
+	  /* If PUSH_ROUNDING is defined, it is possible for the
+	     stack to be momentarily aligned only to that amount,
+	     so we pick the least alignment.  */
+	  if (x == stack_pointer_rtx && PUSH_ARGS)
+	    alignment = MIN ((unsigned HOST_WIDE_INT) PUSH_ROUNDING (1),
+			     alignment);
+#endif
+	  nonzero &= ~(alignment - 1);
+	}
+{
+	unsigned HOST_WIDE_INT nonzero_for_hook = nonzero;
+	rtx new_rtx = rtl_hooks.reg_nonzero_bits (x, mode, known_x,
+					      known_mode, known_ret,
+					      &nonzero_for_hook);
+	if (new_rtx)
+	  nonzero_for_hook &= cached_nonzero_bits (new_rtx, mode, known_x,
+						   known_mode, known_ret);
+	return nonzero_for_hook;
+}
+case CONST_INT:
+#ifdef SHORT_IMMEDIATES_SIGN_EXTEND
+/* If X is negative in MODE, sign-extend the value.  */
+if (INTVAL (x) > 0 && mode_width < BITS_PER_WORD
+	  && 0 != (INTVAL (x) & ((HOST_WIDE_INT) 1 << (mode_width - 1))))
+	return (INTVAL (x) | ((HOST_WIDE_INT) (-1) << mode_width));
+#endif
+return INTVAL (x);
+case MEM:
+#ifdef LOAD_EXTEND_OP
+/* In many, if not most, RISC machines, reading a byte from memory
+	 zeros the rest of the register.  Noticing that fact saves a lot
+	 of extra zero-extends.  */
+if (LOAD_EXTEND_OP (GET_MODE (x)) == ZERO_EXTEND)
+	nonzero &= GET_MODE_MASK (GET_MODE (x));
+#endif
+break;
+case EQ:  case NE:
+case UNEQ:  case LTGT:
+case GT:  case GTU:  case UNGT:
+case LT:  case LTU:  case UNLT:
+case GE:  case GEU:  case UNGE:
+case LE:  case LEU:  case UNLE:
+case UNORDERED: case ORDERED:
+/* If this produces an integer result, we know which bits are set.
+	 Code here used to clear bits outside the mode of X, but that is
+	 now done above.  */
+/* Mind that MODE is the mode the caller wants to look at this
+	 operation in, and not the actual operation mode.  We can wind
+	 up with (subreg:DI (gt:V4HI x y)), and we don't have anything
+	 that describes the results of a vector compare.  */
+if (GET_MODE_CLASS (GET_MODE (x)) == MODE_INT
+	  && mode_width <= HOST_BITS_PER_WIDE_INT)
+	nonzero = STORE_FLAG_VALUE;
+break;
+case NEG:
+#if 0
+/* Disabled to avoid exponential mutual recursion between nonzero_bits
+	 and num_sign_bit_copies.  */
+if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (x))
+	  == GET_MODE_BITSIZE (GET_MODE (x)))
+	nonzero = 1;
+#endif
+if (GET_MODE_SIZE (GET_MODE (x)) < mode_width)
+	nonzero |= (GET_MODE_MASK (mode) & ~GET_MODE_MASK (GET_MODE (x)));
+break;
+case ABS:
+#if 0
+/* Disabled to avoid exponential mutual recursion between nonzero_bits
+	 and num_sign_bit_copies.  */
+if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (x))
+	  == GET_MODE_BITSIZE (GET_MODE (x)))
+	nonzero = 1;
+#endif
+break;
+case TRUNCATE:
+nonzero &= (cached_nonzero_bits (XEXP (x, 0), mode,
+				       known_x, known_mode, known_ret)
+		  & GET_MODE_MASK (mode));
+break;
+case ZERO_EXTEND:
+nonzero &= cached_nonzero_bits (XEXP (x, 0), mode,
+				      known_x, known_mode, known_ret);
+if (GET_MODE (XEXP (x, 0)) != VOIDmode)
+	nonzero &= GET_MODE_MASK (GET_MODE (XEXP (x, 0)));
+break;
+case SIGN_EXTEND:
+/* If the sign bit is known clear, this is the same as ZERO_EXTEND.
+	 Otherwise, show all the bits in the outer mode but not the inner
+	 may be nonzero.  */
+inner_nz = cached_nonzero_bits (XEXP (x, 0), mode,
+				      known_x, known_mode, known_ret);
+if (GET_MODE (XEXP (x, 0)) != VOIDmode)
+	{
+	  inner_nz &= GET_MODE_MASK (GET_MODE (XEXP (x, 0)));
+	  if (inner_nz
+	      & (((HOST_WIDE_INT) 1
+		  << (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0))) - 1))))
+	    inner_nz |= (GET_MODE_MASK (mode)
+			 & ~GET_MODE_MASK (GET_MODE (XEXP (x, 0))));
+	}
+nonzero &= inner_nz;
+break;
+case AND:
+nonzero &= cached_nonzero_bits (XEXP (x, 0), mode,
+				       known_x, known_mode, known_ret)
+		 & cached_nonzero_bits (XEXP (x, 1), mode,
+					known_x, known_mode, known_ret);
+break;
+case XOR:   case IOR:
+case UMIN:  case UMAX:  case SMIN:  case SMAX:
+{
+	unsigned HOST_WIDE_INT nonzero0 =
+	  cached_nonzero_bits (XEXP (x, 0), mode,
+			       known_x, known_mode, known_ret);
+	/* Don't call nonzero_bits for the second time if it cannot change
+	   anything.  */
+	if ((nonzero & nonzero0) != nonzero)
+	  nonzero &= nonzero0
+		     | cached_nonzero_bits (XEXP (x, 1), mode,
+					    known_x, known_mode, known_ret);
+}
+break;
+case PLUS:  case MINUS:
+case MULT:
+case DIV:   case UDIV:
+case MOD:   case UMOD:
+/* We can apply the rules of arithmetic to compute the number of
+	 high- and low-order zero bits of these operations.  We start by
+	 computing the width (position of the highest-order nonzero bit)
+	 and the number of low-order zero bits for each value.  */
+{
+	unsigned HOST_WIDE_INT nz0 =
+	  cached_nonzero_bits (XEXP (x, 0), mode,
+			       known_x, known_mode, known_ret);
+	unsigned HOST_WIDE_INT nz1 =
+	  cached_nonzero_bits (XEXP (x, 1), mode,
+			       known_x, known_mode, known_ret);
+	int sign_index = GET_MODE_BITSIZE (GET_MODE (x)) - 1;
+	int width0 = floor_log2 (nz0) + 1;
+	int width1 = floor_log2 (nz1) + 1;
+	int low0 = floor_log2 (nz0 & -nz0);
+	int low1 = floor_log2 (nz1 & -nz1);
+	HOST_WIDE_INT op0_maybe_minusp
+	  = (nz0 & ((HOST_WIDE_INT) 1 << sign_index));
+	HOST_WIDE_INT op1_maybe_minusp
+	  = (nz1 & ((HOST_WIDE_INT) 1 << sign_index));
+	unsigned int result_width = mode_width;
+	int result_low = 0;
+	switch (code)
+	  {
+	  case PLUS:
+	    result_width = MAX (width0, width1) + 1;
+	    result_low = MIN (low0, low1);
+	    break;
+	  case MINUS:
+	    result_low = MIN (low0, low1);
+	    break;
+	  case MULT:
+	    result_width = width0 + width1;
+	    result_low = low0 + low1;
+	    break;
+	  case DIV:
+	    if (width1 == 0)
+	      break;
+	    if (! op0_maybe_minusp && ! op1_maybe_minusp)
+	      result_width = width0;
+	    break;
+	  case UDIV:
+	    if (width1 == 0)
+	      break;
+	    result_width = width0;
+	    break;
+	  case MOD:
+	    if (width1 == 0)
+	      break;
+	    if (! op0_maybe_minusp && ! op1_maybe_minusp)
+	      result_width = MIN (width0, width1);
+	    result_low = MIN (low0, low1);
+	    break;
+	  case UMOD:
+	    if (width1 == 0)
+	      break;
+	    result_width = MIN (width0, width1);
+	    result_low = MIN (low0, low1);
+	    break;
+	  default:
+	    gcc_unreachable ();
+	  }
+	if (result_width < mode_width)
+	  nonzero &= ((HOST_WIDE_INT) 1 << result_width) - 1;
+	if (result_low > 0)
+	  nonzero &= ~(((HOST_WIDE_INT) 1 << result_low) - 1);
+#ifdef POINTERS_EXTEND_UNSIGNED
+	/* If pointers extend unsigned and this is an addition or subtraction
+	   to a pointer in Pmode, all the bits above ptr_mode are known to be
+	   zero.  */
+	if (POINTERS_EXTEND_UNSIGNED > 0 && GET_MODE (x) == Pmode
+	    && (code == PLUS || code == MINUS)
+	    && REG_P (XEXP (x, 0)) && REG_POINTER (XEXP (x, 0)))
+	  nonzero &= GET_MODE_MASK (ptr_mode);
+#endif
+}
+break;
+case ZERO_EXTRACT:
+if (GET_CODE (XEXP (x, 1)) == CONST_INT
+	  && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT)
+	nonzero &= ((HOST_WIDE_INT) 1 << INTVAL (XEXP (x, 1))) - 1;
+break;
+case SUBREG:
+/* If this is a SUBREG formed for a promoted variable that has
+	 been zero-extended, we know that at least the high-order bits
+	 are zero, though others might be too.  */
+if (SUBREG_PROMOTED_VAR_P (x) && SUBREG_PROMOTED_UNSIGNED_P (x) > 0)
+	nonzero = GET_MODE_MASK (GET_MODE (x))
+		  & cached_nonzero_bits (SUBREG_REG (x), GET_MODE (x),
+					 known_x, known_mode, known_ret);
+/* If the inner mode is a single word for both the host and target
+	 machines, we can compute this from which bits of the inner
+	 object might be nonzero.  */
+if (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) <= BITS_PER_WORD
+	  && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x)))
+	      <= HOST_BITS_PER_WIDE_INT))
+	{
+	  nonzero &= cached_nonzero_bits (SUBREG_REG (x), mode,
+					  known_x, known_mode, known_ret);
+#if defined (WORD_REGISTER_OPERATIONS) && defined (LOAD_EXTEND_OP)
+	  /* If this is a typical RISC machine, we only have to worry
+	     about the way loads are extended.  */
+	  if ((LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) == SIGN_EXTEND
+	       ? (((nonzero
+		    & (((unsigned HOST_WIDE_INT) 1
+			<< (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))) - 1))))
+		   != 0))
+	       : LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) != ZERO_EXTEND)
+	      || !MEM_P (SUBREG_REG (x)))
+#endif
+	    {
+	      /* On many CISC machines, accessing an object in a wider mode
+		 causes the high-order bits to become undefined.  So they are
+		 not known to be zero.  */
+	      if (GET_MODE_SIZE (GET_MODE (x))
+		  > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
+		nonzero |= (GET_MODE_MASK (GET_MODE (x))
+			    & ~GET_MODE_MASK (GET_MODE (SUBREG_REG (x))));
+	    }
+	}
+break;
+case ASHIFTRT:
+case LSHIFTRT:
+case ASHIFT:
+case ROTATE:
+/* The nonzero bits are in two classes: any bits within MODE
+	 that aren't in GET_MODE (x) are always significant.  The rest of the
+	 nonzero bits are those that are significant in the operand of
+	 the shift when shifted the appropriate number of bits.  This
+	 shows that high-order bits are cleared by the right shift and
+	 low-order bits by left shifts.  */
+if (GET_CODE (XEXP (x, 1)) == CONST_INT
+	  && INTVAL (XEXP (x, 1)) >= 0
+	  && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT
+	  && INTVAL (XEXP (x, 1)) < GET_MODE_BITSIZE (GET_MODE (x)))
+	{
+	  enum machine_mode inner_mode = GET_MODE (x);
+	  unsigned int width = GET_MODE_BITSIZE (inner_mode);
+	  int count = INTVAL (XEXP (x, 1));
+	  unsigned HOST_WIDE_INT mode_mask = GET_MODE_MASK (inner_mode);
+	  unsigned HOST_WIDE_INT op_nonzero =
+	    cached_nonzero_bits (XEXP (x, 0), mode,
+				 known_x, known_mode, known_ret);
+	  unsigned HOST_WIDE_INT inner = op_nonzero & mode_mask;
+	  unsigned HOST_WIDE_INT outer = 0;
+	  if (mode_width > width)
+	    outer = (op_nonzero & nonzero & ~mode_mask);
+	  if (code == LSHIFTRT)
+	    inner >>= count;
+	  else if (code == ASHIFTRT)
+	    {
+	      inner >>= count;
+	      /* If the sign bit may have been nonzero before the shift, we
+		 need to mark all the places it could have been copied to
+		 by the shift as possibly nonzero.  */
+	      if (inner & ((HOST_WIDE_INT) 1 << (width - 1 - count)))
+		inner |= (((HOST_WIDE_INT) 1 << count) - 1) << (width - count);
+	    }
+	  else if (code == ASHIFT)
+	    inner <<= count;
+	  else
+	    inner = ((inner << (count % width)
+		      | (inner >> (width - (count % width)))) & mode_mask);
+	  nonzero &= (outer | inner);
+	}
+break;
+case FFS:
+case POPCOUNT:
+/* This is at most the number of bits in the mode.  */
+nonzero = ((HOST_WIDE_INT) 2 << (floor_log2 (mode_width))) - 1;
+break;
+case CLZ:
+/* If CLZ has a known value at zero, then the nonzero bits are
+	 that value, plus the number of bits in the mode minus one.  */
+if (CLZ_DEFINED_VALUE_AT_ZERO (mode, nonzero))
+	nonzero |= ((HOST_WIDE_INT) 1 << (floor_log2 (mode_width))) - 1;
+else
+	nonzero = -1;
+break;
+case CTZ:
+/* If CTZ has a known value at zero, then the nonzero bits are
+	 that value, plus the number of bits in the mode minus one.  */
+if (CTZ_DEFINED_VALUE_AT_ZERO (mode, nonzero))
+	nonzero |= ((HOST_WIDE_INT) 1 << (floor_log2 (mode_width))) - 1;
+else
+	nonzero = -1;
+break;
+case PARITY:
+nonzero = 1;
+break;
+case IF_THEN_ELSE:
+{
+	unsigned HOST_WIDE_INT nonzero_true =
+	  cached_nonzero_bits (XEXP (x, 1), mode,
+			       known_x, known_mode, known_ret);
+	/* Don't call nonzero_bits for the second time if it cannot change
+	   anything.  */
+	if ((nonzero & nonzero_true) != nonzero)
+	  nonzero &= nonzero_true
+		     | cached_nonzero_bits (XEXP (x, 2), mode,
+					    known_x, known_mode, known_ret);
+}
+break;
+default:
+break;
+}
+return nonzero;
+}
+/* See the macro definition above.  */
+#undef cached_num_sign_bit_copies
+/* The function cached_num_sign_bit_copies is a wrapper around
+num_sign_bit_copies1.  It avoids exponential behavior in
+num_sign_bit_copies1 when X has identical subexpressions on the
+first or the second level.  */
+static unsigned int
+cached_num_sign_bit_copies (const_rtx x, enum machine_mode mode, const_rtx known_x,
+			    enum machine_mode known_mode,
+			    unsigned int known_ret)
+{
+if (x == known_x && mode == known_mode)
+return known_ret;
+/* Try to find identical subexpressions.  If found call
+num_sign_bit_copies1 on X with the subexpressions as KNOWN_X and
+the precomputed value for the subexpression as KNOWN_RET.  */
+if (ARITHMETIC_P (x))
+{
+rtx x0 = XEXP (x, 0);
+rtx x1 = XEXP (x, 1);
+/* Check the first level.  */
+if (x0 == x1)
+	return
+	  num_sign_bit_copies1 (x, mode, x0, mode,
+				cached_num_sign_bit_copies (x0, mode, known_x,
+							    known_mode,
+							    known_ret));
+/* Check the second level.  */
+if (ARITHMETIC_P (x0)
+	  && (x1 == XEXP (x0, 0) || x1 == XEXP (x0, 1)))
+	return
+	  num_sign_bit_copies1 (x, mode, x1, mode,
+				cached_num_sign_bit_copies (x1, mode, known_x,
+							    known_mode,
+							    known_ret));
+if (ARITHMETIC_P (x1)
+	  && (x0 == XEXP (x1, 0) || x0 == XEXP (x1, 1)))
+	return
+	  num_sign_bit_copies1 (x, mode, x0, mode,
+				cached_num_sign_bit_copies (x0, mode, known_x,
+							    known_mode,
+							    known_ret));
+}
+return num_sign_bit_copies1 (x, mode, known_x, known_mode, known_ret);
+}
+/* Return the number of bits at the high-order end of X that are known to
+be equal to the sign bit.  X will be used in mode MODE; if MODE is
+VOIDmode, X will be used in its own mode.  The returned value  will always
+be between 1 and the number of bits in MODE.  */
+static unsigned int
+num_sign_bit_copies1 (const_rtx x, enum machine_mode mode, const_rtx known_x,
+		      enum machine_mode known_mode,
+		      unsigned int known_ret)
+{
+enum rtx_code code = GET_CODE (x);
+unsigned int bitwidth = GET_MODE_BITSIZE (mode);
+int num0, num1, result;
+unsigned HOST_WIDE_INT nonzero;
+/* If we weren't given a mode, use the mode of X.  If the mode is still
+VOIDmode, we don't know anything.  Likewise if one of the modes is
+floating-point.  */
+if (mode == VOIDmode)
+mode = GET_MODE (x);
+if (mode == VOIDmode || FLOAT_MODE_P (mode) || FLOAT_MODE_P (GET_MODE (x))
+|| VECTOR_MODE_P (GET_MODE (x)) || VECTOR_MODE_P (mode))
+return 1;
+/* For a smaller object, just ignore the high bits.  */
+if (bitwidth < GET_MODE_BITSIZE (GET_MODE (x)))
+{
+num0 = cached_num_sign_bit_copies (x, GET_MODE (x),
+					 known_x, known_mode, known_ret);
+return MAX (1,
+		  num0 - (int) (GET_MODE_BITSIZE (GET_MODE (x)) - bitwidth));
+}
+if (GET_MODE (x) != VOIDmode && bitwidth > GET_MODE_BITSIZE (GET_MODE (x)))
+{
+#ifndef WORD_REGISTER_OPERATIONS
+/* If this machine does not do all register operations on the entire
+register and MODE is wider than the mode of X, we can say nothing
+at all about the high-order bits.  */
+return 1;
+#else
+/* Likewise on machines that do, if the mode of the object is smaller
+	 than a word and loads of that size don't sign extend, we can say
+	 nothing about the high order bits.  */
+if (GET_MODE_BITSIZE (GET_MODE (x)) < BITS_PER_WORD
+#ifdef LOAD_EXTEND_OP
+	  && LOAD_EXTEND_OP (GET_MODE (x)) != SIGN_EXTEND
+#endif
+	  )
+	return 1;
+#endif
+}
+switch (code)
+{
+case REG:
+#if defined(POINTERS_EXTEND_UNSIGNED) && !defined(HAVE_ptr_extend)
+/* If pointers extend signed and this is a pointer in Pmode, say that
+	 all the bits above ptr_mode are known to be sign bit copies.  */
+if (! POINTERS_EXTEND_UNSIGNED && GET_MODE (x) == Pmode && mode == Pmode
+	  && REG_POINTER (x))
+	return GET_MODE_BITSIZE (Pmode) - GET_MODE_BITSIZE (ptr_mode) + 1;
+#endif
+{
+	unsigned int copies_for_hook = 1, copies = 1;
+	rtx new_rtx = rtl_hooks.reg_num_sign_bit_copies (x, mode, known_x,
+						     known_mode, known_ret,
+						     &copies_for_hook);
+	if (new_rtx)
+	  copies = cached_num_sign_bit_copies (new_rtx, mode, known_x,
+					       known_mode, known_ret);
+	if (copies > 1 || copies_for_hook > 1)
+	  return MAX (copies, copies_for_hook);
+	/* Else, use nonzero_bits to guess num_sign_bit_copies (see below).  */
+}
+break;
+case MEM:
+#ifdef LOAD_EXTEND_OP
+/* Some RISC machines sign-extend all loads of smaller than a word.  */
+if (LOAD_EXTEND_OP (GET_MODE (x)) == SIGN_EXTEND)
+	return MAX (1, ((int) bitwidth
+			- (int) GET_MODE_BITSIZE (GET_MODE (x)) + 1));
+#endif
+break;
+case CONST_INT:
+/* If the constant is negative, take its 1's complement and remask.
+	 Then see how many zero bits we have.  */
+nonzero = INTVAL (x) & GET_MODE_MASK (mode);
+if (bitwidth <= HOST_BITS_PER_WIDE_INT
+	  && (nonzero & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
+	nonzero = (~nonzero) & GET_MODE_MASK (mode);
+return (nonzero == 0 ? bitwidth : bitwidth - floor_log2 (nonzero) - 1);
+case SUBREG:
+/* If this is a SUBREG for a promoted object that is sign-extended
+	 and we are looking at it in a wider mode, we know that at least the
+	 high-order bits are known to be sign bit copies.  */
+if (SUBREG_PROMOTED_VAR_P (x) && ! SUBREG_PROMOTED_UNSIGNED_P (x))
+	{
+	  num0 = cached_num_sign_bit_copies (SUBREG_REG (x), mode,
+					     known_x, known_mode, known_ret);
+	  return MAX ((int) bitwidth
+		      - (int) GET_MODE_BITSIZE (GET_MODE (x)) + 1,
+		      num0);
+	}
+/* For a smaller object, just ignore the high bits.  */
+if (bitwidth <= GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))))
+	{
+	  num0 = cached_num_sign_bit_copies (SUBREG_REG (x), VOIDmode,
+					     known_x, known_mode, known_ret);
+	  return MAX (1, (num0
+			  - (int) (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x)))
+				   - bitwidth)));
+	}
+#ifdef WORD_REGISTER_OPERATIONS
+#ifdef LOAD_EXTEND_OP
+/* For paradoxical SUBREGs on machines where all register operations
+	 affect the entire register, just look inside.  Note that we are
+	 passing MODE to the recursive call, so the number of sign bit copies
+	 will remain relative to that mode, not the inner mode.  */
+/* This works only if loads sign extend.  Otherwise, if we get a
+	 reload for the inner part, it may be loaded from the stack, and
+	 then we lose all sign bit copies that existed before the store
+	 to the stack.  */
+if ((GET_MODE_SIZE (GET_MODE (x))
+	   > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
+	  && LOAD_EXTEND_OP (GET_MODE (SUBREG_REG (x))) == SIGN_EXTEND
+	  && MEM_P (SUBREG_REG (x)))
+	return cached_num_sign_bit_copies (SUBREG_REG (x), mode,
+					   known_x, known_mode, known_ret);
+#endif
+#endif
+break;
+case SIGN_EXTRACT:
+if (GET_CODE (XEXP (x, 1)) == CONST_INT)
+	return MAX (1, (int) bitwidth - INTVAL (XEXP (x, 1)));
+break;
+case SIGN_EXTEND:
+return (bitwidth - GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0)))
+	      + cached_num_sign_bit_copies (XEXP (x, 0), VOIDmode,
+					    known_x, known_mode, known_ret));
+case TRUNCATE:
+/* For a smaller object, just ignore the high bits.  */
+num0 = cached_num_sign_bit_copies (XEXP (x, 0), VOIDmode,
+					 known_x, known_mode, known_ret);
+return MAX (1, (num0 - (int) (GET_MODE_BITSIZE (GET_MODE (XEXP (x, 0)))
+				    - bitwidth)));
+case NOT:
+return cached_num_sign_bit_copies (XEXP (x, 0), mode,
+					 known_x, known_mode, known_ret);
+case ROTATE:       case ROTATERT:
+/* If we are rotating left by a number of bits less than the number
+	 of sign bit copies, we can just subtract that amount from the
+	 number.  */
+if (GET_CODE (XEXP (x, 1)) == CONST_INT
+	  && INTVAL (XEXP (x, 1)) >= 0
+	  && INTVAL (XEXP (x, 1)) < (int) bitwidth)
+	{
+	  num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+					     known_x, known_mode, known_ret);
+	  return MAX (1, num0 - (code == ROTATE ? INTVAL (XEXP (x, 1))
+				 : (int) bitwidth - INTVAL (XEXP (x, 1))));
+	}
+break;
+case NEG:
+/* In general, this subtracts one sign bit copy.  But if the value
+	 is known to be positive, the number of sign bit copies is the
+	 same as that of the input.  Finally, if the input has just one bit
+	 that might be nonzero, all the bits are copies of the sign bit.  */
+num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+					 known_x, known_mode, known_ret);
+if (bitwidth > HOST_BITS_PER_WIDE_INT)
+	return num0 > 1 ? num0 - 1 : 1;
+nonzero = nonzero_bits (XEXP (x, 0), mode);
+if (nonzero == 1)
+	return bitwidth;
+if (num0 > 1
+	  && (((HOST_WIDE_INT) 1 << (bitwidth - 1)) & nonzero))
+	num0--;
+return num0;
+case IOR:   case AND:   case XOR:
+case SMIN:  case SMAX:  case UMIN:  case UMAX:
+/* Logical operations will preserve the number of sign-bit copies.
+	 MIN and MAX operations always return one of the operands.  */
+num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+					 known_x, known_mode, known_ret);
+num1 = cached_num_sign_bit_copies (XEXP (x, 1), mode,
+					 known_x, known_mode, known_ret);
+/* If num1 is clearing some of the top bits then regardless of
+	 the other term, we are guaranteed to have at least that many
+	 high-order zero bits.  */
+if (code == AND
+	  && num1 > 1
+	  && bitwidth <= HOST_BITS_PER_WIDE_INT
+	  && GET_CODE (XEXP (x, 1)) == CONST_INT
+	  && !(INTVAL (XEXP (x, 1)) & ((HOST_WIDE_INT) 1 << (bitwidth - 1))))
+	return num1;
+/* Similarly for IOR when setting high-order bits.  */
+if (code == IOR
+	  && num1 > 1
+	  && bitwidth <= HOST_BITS_PER_WIDE_INT
+	  && GET_CODE (XEXP (x, 1)) == CONST_INT
+	  && (INTVAL (XEXP (x, 1)) & ((HOST_WIDE_INT) 1 << (bitwidth - 1))))
+	return num1;
+return MIN (num0, num1);
+case PLUS:  case MINUS:
+/* For addition and subtraction, we can have a 1-bit carry.  However,
+	 if we are subtracting 1 from a positive number, there will not
+	 be such a carry.  Furthermore, if the positive number is known to
+	 be 0 or 1, we know the result is either -1 or 0.  */
+if (code == PLUS && XEXP (x, 1) == constm1_rtx
+	  && bitwidth <= HOST_BITS_PER_WIDE_INT)
+	{
+	  nonzero = nonzero_bits (XEXP (x, 0), mode);
+	  if ((((HOST_WIDE_INT) 1 << (bitwidth - 1)) & nonzero) == 0)
+	    return (nonzero == 1 || nonzero == 0 ? bitwidth
+		    : bitwidth - floor_log2 (nonzero) - 1);
+	}
+num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+					 known_x, known_mode, known_ret);
+num1 = cached_num_sign_bit_copies (XEXP (x, 1), mode,
+					 known_x, known_mode, known_ret);
+result = MAX (1, MIN (num0, num1) - 1);
+#ifdef POINTERS_EXTEND_UNSIGNED
+/* If pointers extend signed and this is an addition or subtraction
+	 to a pointer in Pmode, all the bits above ptr_mode are known to be
+	 sign bit copies.  */
+if (! POINTERS_EXTEND_UNSIGNED && GET_MODE (x) == Pmode
+	  && (code == PLUS || code == MINUS)
+	  && REG_P (XEXP (x, 0)) && REG_POINTER (XEXP (x, 0)))
+	result = MAX ((int) (GET_MODE_BITSIZE (Pmode)
+			     - GET_MODE_BITSIZE (ptr_mode) + 1),
+		      result);
+#endif
+return result;
+case MULT:
+/* The number of bits of the product is the sum of the number of
+	 bits of both terms.  However, unless one of the terms if known
+	 to be positive, we must allow for an additional bit since negating
+	 a negative number can remove one sign bit copy.  */
+num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+					 known_x, known_mode, known_ret);
+num1 = cached_num_sign_bit_copies (XEXP (x, 1), mode,
+					 known_x, known_mode, known_ret);
+result = bitwidth - (bitwidth - num0) - (bitwidth - num1);
+if (result > 0
+	  && (bitwidth > HOST_BITS_PER_WIDE_INT
+	      || (((nonzero_bits (XEXP (x, 0), mode)
+		    & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
+		  && ((nonzero_bits (XEXP (x, 1), mode)
+		       & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0))))
+	result--;
+return MAX (1, result);
+case UDIV:
+/* The result must be <= the first operand.  If the first operand
+	 has the high bit set, we know nothing about the number of sign
+	 bit copies.  */
+if (bitwidth > HOST_BITS_PER_WIDE_INT)
+	return 1;
+else if ((nonzero_bits (XEXP (x, 0), mode)
+		& ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
+	return 1;
+else
+	return cached_num_sign_bit_copies (XEXP (x, 0), mode,
+					   known_x, known_mode, known_ret);
+case UMOD:
+/* The result must be <= the second operand.  */
+return cached_num_sign_bit_copies (XEXP (x, 1), mode,
+					   known_x, known_mode, known_ret);
+case DIV:
+/* Similar to unsigned division, except that we have to worry about
+	 the case where the divisor is negative, in which case we have
+	 to add 1.  */
+result = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+					   known_x, known_mode, known_ret);
+if (result > 1
+	  && (bitwidth > HOST_BITS_PER_WIDE_INT
+	      || (nonzero_bits (XEXP (x, 1), mode)
+		  & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0))
+	result--;
+return result;
+case MOD:
+result = cached_num_sign_bit_copies (XEXP (x, 1), mode,
+					   known_x, known_mode, known_ret);
+if (result > 1
+	  && (bitwidth > HOST_BITS_PER_WIDE_INT
+	      || (nonzero_bits (XEXP (x, 1), mode)
+		  & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0))
+	result--;
+return result;
+case ASHIFTRT:
+/* Shifts by a constant add to the number of bits equal to the
+	 sign bit.  */
+num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+					 known_x, known_mode, known_ret);
+if (GET_CODE (XEXP (x, 1)) == CONST_INT
+	  && INTVAL (XEXP (x, 1)) > 0
+	  && INTVAL (XEXP (x, 1)) < GET_MODE_BITSIZE (GET_MODE (x)))
+	num0 = MIN ((int) bitwidth, num0 + INTVAL (XEXP (x, 1)));
+return num0;
+case ASHIFT:
+/* Left shifts destroy copies.  */
+if (GET_CODE (XEXP (x, 1)) != CONST_INT
+	  || INTVAL (XEXP (x, 1)) < 0
+	  || INTVAL (XEXP (x, 1)) >= (int) bitwidth
+	  || INTVAL (XEXP (x, 1)) >= GET_MODE_BITSIZE (GET_MODE (x)))
+	return 1;
+num0 = cached_num_sign_bit_copies (XEXP (x, 0), mode,
+					 known_x, known_mode, known_ret);
+return MAX (1, num0 - INTVAL (XEXP (x, 1)));
+case IF_THEN_ELSE:
+num0 = cached_num_sign_bit_copies (XEXP (x, 1), mode,
+					 known_x, known_mode, known_ret);
+num1 = cached_num_sign_bit_copies (XEXP (x, 2), mode,
+					 known_x, known_mode, known_ret);
+return MIN (num0, num1);
+case EQ:  case NE:  case GE:  case GT:  case LE:  case LT:
+case UNEQ:  case LTGT:  case UNGE:  case UNGT:  case UNLE:  case UNLT:
+case GEU: case GTU: case LEU: case LTU:
+case UNORDERED: case ORDERED:
+/* If the constant is negative, take its 1's complement and remask.
+	 Then see how many zero bits we have.  */
+nonzero = STORE_FLAG_VALUE;
+if (bitwidth <= HOST_BITS_PER_WIDE_INT
+	  && (nonzero & ((HOST_WIDE_INT) 1 << (bitwidth - 1))) != 0)
+	nonzero = (~nonzero) & GET_MODE_MASK (mode);
+return (nonzero == 0 ? bitwidth : bitwidth - floor_log2 (nonzero) - 1);
+default:
+break;
+}
+/* If we haven't been able to figure it out by one of the above rules,
+see if some of the high-order bits are known to be zero.  If so,
+count those bits and return one less than that amount.  If we can't
+safely compute the mask for this mode, always return BITWIDTH.  */
+bitwidth = GET_MODE_BITSIZE (mode);
+if (bitwidth > HOST_BITS_PER_WIDE_INT)
+return 1;
+nonzero = nonzero_bits (x, mode);
+return nonzero & ((HOST_WIDE_INT) 1 << (bitwidth - 1))
+	 ? 1 : bitwidth - floor_log2 (nonzero) - 1;
+}
+/* Calculate the rtx_cost of a single instruction.  A return value of
+zero indicates an instruction pattern without a known cost.  */
+int
+insn_rtx_cost (rtx pat, bool speed)
+{
+int i, cost;
+rtx set;
+/* Extract the single set rtx from the instruction pattern.
+We can't use single_set since we only have the pattern.  */
+if (GET_CODE (pat) == SET)
+set = pat;
+else if (GET_CODE (pat) == PARALLEL)
+{
+set = NULL_RTX;
+for (i = 0; i < XVECLEN (pat, 0); i++)
+	{
+	  rtx x = XVECEXP (pat, 0, i);
+	  if (GET_CODE (x) == SET)
+	    {
+	      if (set)
+		return 0;
+	      set = x;
+	    }
+	}
+if (!set)
+	return 0;
+}
+else
+return 0;
+cost = rtx_cost (SET_SRC (set), SET, speed);
+return cost > 0 ? cost : COSTS_N_INSNS (1);
+}
+/* Given an insn INSN and condition COND, return the condition in a
+canonical form to simplify testing by callers.  Specifically:
+(1) The code will always be a comparison operation (EQ, NE, GT, etc.).
+(2) Both operands will be machine operands; (cc0) will have been replaced.
+(3) If an operand is a constant, it will be the second operand.
+(4) (LE x const) will be replaced with (LT x <const+1>) and similarly
+for GE, GEU, and LEU.
+If the condition cannot be understood, or is an inequality floating-point
+comparison which needs to be reversed, 0 will be returned.
+If REVERSE is nonzero, then reverse the condition prior to canonizing it.
+If EARLIEST is nonzero, it is a pointer to a place where the earliest
+insn used in locating the condition was found.  If a replacement test
+of the condition is desired, it should be placed in front of that
+insn and we will be sure that the inputs are still valid.
+If WANT_REG is nonzero, we wish the condition to be relative to that
+register, if possible.  Therefore, do not canonicalize the condition
+further.  If ALLOW_CC_MODE is nonzero, allow the condition returned
+to be a compare to a CC mode register.
+If VALID_AT_INSN_P, the condition must be valid at both *EARLIEST
+and at INSN.  */
+rtx
+canonicalize_condition (rtx insn, rtx cond, int reverse, rtx *earliest,
+			rtx want_reg, int allow_cc_mode, int valid_at_insn_p)
+{
+enum rtx_code code;
+rtx prev = insn;
+const_rtx set;
+rtx tem;
+rtx op0, op1;
+int reverse_code = 0;
+enum machine_mode mode;
+basic_block bb = BLOCK_FOR_INSN (insn);
+code = GET_CODE (cond);
+mode = GET_MODE (cond);
+op0 = XEXP (cond, 0);
+op1 = XEXP (cond, 1);
+if (reverse)
+code = reversed_comparison_code (cond, insn);
+if (code == UNKNOWN)
+return 0;
+if (earliest)
+*earliest = insn;
+/* If we are comparing a register with zero, see if the register is set
+in the previous insn to a COMPARE or a comparison operation.  Perform
+the same tests as a function of STORE_FLAG_VALUE as find_comparison_args
+in cse.c  */
+while ((GET_RTX_CLASS (code) == RTX_COMPARE
+	  || GET_RTX_CLASS (code) == RTX_COMM_COMPARE)
+	 && op1 == CONST0_RTX (GET_MODE (op0))
+	 && op0 != want_reg)
+{
+/* Set nonzero when we find something of interest.  */
+rtx x = 0;
+#ifdef HAVE_cc0
+/* If comparison with cc0, import actual comparison from compare
+	 insn.  */
+if (op0 == cc0_rtx)
+	{
+	  if ((prev = prev_nonnote_insn (prev)) == 0
+	      || !NONJUMP_INSN_P (prev)
+	      || (set = single_set (prev)) == 0
+	      || SET_DEST (set) != cc0_rtx)
+	    return 0;
+	  op0 = SET_SRC (set);
+	  op1 = CONST0_RTX (GET_MODE (op0));
+	  if (earliest)
+	    *earliest = prev;
+	}
+#endif
+/* If this is a COMPARE, pick up the two things being compared.  */
+if (GET_CODE (op0) == COMPARE)
+	{
+	  op1 = XEXP (op0, 1);
+	  op0 = XEXP (op0, 0);
+	  continue;
+	}
+else if (!REG_P (op0))
+	break;
+/* Go back to the previous insn.  Stop if it is not an INSN.  We also
+	 stop if it isn't a single set or if it has a REG_INC note because
+	 we don't want to bother dealing with it.  */
+if ((prev = prev_nonnote_insn (prev)) == 0
+	  || !NONJUMP_INSN_P (prev)
+	  || FIND_REG_INC_NOTE (prev, NULL_RTX)
+	  /* In cfglayout mode, there do not have to be labels at the
+	     beginning of a block, or jumps at the end, so the previous
+	     conditions would not stop us when we reach bb boundary.  */
+	  || BLOCK_FOR_INSN (prev) != bb)
+	break;
+set = set_of (op0, prev);
+if (set
+	  && (GET_CODE (set) != SET
+	      || !rtx_equal_p (SET_DEST (set), op0)))
+	break;
+/* If this is setting OP0, get what it sets it to if it looks
+	 relevant.  */
+if (set)
+	{
+	  enum machine_mode inner_mode = GET_MODE (SET_DEST (set));
+#ifdef FLOAT_STORE_FLAG_VALUE
+	  REAL_VALUE_TYPE fsfv;
+#endif
+	  /* ??? We may not combine comparisons done in a CCmode with
+	     comparisons not done in a CCmode.  This is to aid targets
+	     like Alpha that have an IEEE compliant EQ instruction, and
+	     a non-IEEE compliant BEQ instruction.  The use of CCmode is
+	     actually artificial, simply to prevent the combination, but
+	     should not affect other platforms.
+	     However, we must allow VOIDmode comparisons to match either
+	     CCmode or non-CCmode comparison, because some ports have
+	     modeless comparisons inside branch patterns.
+	     ??? This mode check should perhaps look more like the mode check
+	     in simplify_comparison in combine.  */
+	  if ((GET_CODE (SET_SRC (set)) == COMPARE
+	       || (((code == NE
+		     || (code == LT
+			 && GET_MODE_CLASS (inner_mode) == MODE_INT
+			 && (GET_MODE_BITSIZE (inner_mode)
+			     <= HOST_BITS_PER_WIDE_INT)
+			 && (STORE_FLAG_VALUE
+			     & ((HOST_WIDE_INT) 1
+				<< (GET_MODE_BITSIZE (inner_mode) - 1))))
+#ifdef FLOAT_STORE_FLAG_VALUE
+		     || (code == LT
+			 && SCALAR_FLOAT_MODE_P (inner_mode)
+			 && (fsfv = FLOAT_STORE_FLAG_VALUE (inner_mode),
+			     REAL_VALUE_NEGATIVE (fsfv)))
+#endif
+		     ))
+		   && COMPARISON_P (SET_SRC (set))))
+	      && (((GET_MODE_CLASS (mode) == MODE_CC)
+		   == (GET_MODE_CLASS (inner_mode) == MODE_CC))
+		  || mode == VOIDmode || inner_mode == VOIDmode))
+	    x = SET_SRC (set);
+	  else if (((code == EQ
+		     || (code == GE
+			 && (GET_MODE_BITSIZE (inner_mode)
+			     <= HOST_BITS_PER_WIDE_INT)
+			 && GET_MODE_CLASS (inner_mode) == MODE_INT
+			 && (STORE_FLAG_VALUE
+			     & ((HOST_WIDE_INT) 1
+				<< (GET_MODE_BITSIZE (inner_mode) - 1))))
+#ifdef FLOAT_STORE_FLAG_VALUE
+		     || (code == GE
+			 && SCALAR_FLOAT_MODE_P (inner_mode)
+			 && (fsfv = FLOAT_STORE_FLAG_VALUE (inner_mode),
+			     REAL_VALUE_NEGATIVE (fsfv)))
+#endif
+		     ))
+		   && COMPARISON_P (SET_SRC (set))
+		   && (((GET_MODE_CLASS (mode) == MODE_CC)
+			== (GET_MODE_CLASS (inner_mode) == MODE_CC))
+		       || mode == VOIDmode || inner_mode == VOIDmode))
+	    {
+	      reverse_code = 1;
+	      x = SET_SRC (set);
+	    }
+	  else
+	    break;
+	}
+else if (reg_set_p (op0, prev))
+	/* If this sets OP0, but not directly, we have to give up.  */
+	break;
+if (x)
+	{
+	  /* If the caller is expecting the condition to be valid at INSN,
+	     make sure X doesn't change before INSN.  */
+	  if (valid_at_insn_p)
+	    if (modified_in_p (x, prev) || modified_between_p (x, prev, insn))
+	      break;
+	  if (COMPARISON_P (x))
+	    code = GET_CODE (x);
+	  if (reverse_code)
+	    {
+	      code = reversed_comparison_code (x, prev);
+	      if (code == UNKNOWN)
+		return 0;
+	      reverse_code = 0;
+	    }
+	  op0 = XEXP (x, 0), op1 = XEXP (x, 1);
+	  if (earliest)
+	    *earliest = prev;
+	}
+}
+/* If constant is first, put it last.  */
+if (CONSTANT_P (op0))
+code = swap_condition (code), tem = op0, op0 = op1, op1 = tem;
+/* If OP0 is the result of a comparison, we weren't able to find what
+was really being compared, so fail.  */
+if (!allow_cc_mode
+&& GET_MODE_CLASS (GET_MODE (op0)) == MODE_CC)
+return 0;
+/* Canonicalize any ordered comparison with integers involving equality
+if we can do computations in the relevant mode and we do not
+overflow.  */
+if (GET_MODE_CLASS (GET_MODE (op0)) != MODE_CC
+&& GET_CODE (op1) == CONST_INT
+&& GET_MODE (op0) != VOIDmode
+&& GET_MODE_BITSIZE (GET_MODE (op0)) <= HOST_BITS_PER_WIDE_INT)
+{
+HOST_WIDE_INT const_val = INTVAL (op1);
+unsigned HOST_WIDE_INT uconst_val = const_val;
+unsigned HOST_WIDE_INT max_val
+	= (unsigned HOST_WIDE_INT) GET_MODE_MASK (GET_MODE (op0));
+switch (code)
+	{
+	case LE:
+	  if ((unsigned HOST_WIDE_INT) const_val != max_val >> 1)
+	    code = LT, op1 = gen_int_mode (const_val + 1, GET_MODE (op0));
+	  break;
+	/* When cross-compiling, const_val might be sign-extended from
+	   BITS_PER_WORD to HOST_BITS_PER_WIDE_INT */
+	case GE:
+	  if ((HOST_WIDE_INT) (const_val & max_val)
+	      != (((HOST_WIDE_INT) 1
+		   << (GET_MODE_BITSIZE (GET_MODE (op0)) - 1))))
+	    code = GT, op1 = gen_int_mode (const_val - 1, GET_MODE (op0));
+	  break;
+	case LEU:
+	  if (uconst_val < max_val)
+	    code = LTU, op1 = gen_int_mode (uconst_val + 1, GET_MODE (op0));
+	  break;
+	case GEU:
+	  if (uconst_val != 0)
+	    code = GTU, op1 = gen_int_mode (uconst_val - 1, GET_MODE (op0));
+	  break;
+	default:
+	  break;
+	}
+}
+/* Never return CC0; return zero instead.  */
+if (CC0_P (op0))
+return 0;
+return gen_rtx_fmt_ee (code, VOIDmode, op0, op1);
+}
+/* Given a jump insn JUMP, return the condition that will cause it to branch
+to its JUMP_LABEL.  If the condition cannot be understood, or is an
+inequality floating-point comparison which needs to be reversed, 0 will
+be returned.
+If EARLIEST is nonzero, it is a pointer to a place where the earliest
+insn used in locating the condition was found.  If a replacement test
+of the condition is desired, it should be placed in front of that
+insn and we will be sure that the inputs are still valid.  If EARLIEST
+is null, the returned condition will be valid at INSN.
+If ALLOW_CC_MODE is nonzero, allow the condition returned to be a
+compare CC mode register.
+VALID_AT_INSN_P is the same as for canonicalize_condition.  */
+rtx
+get_condition (rtx jump, rtx *earliest, int allow_cc_mode, int valid_at_insn_p)
+{
+rtx cond;
+int reverse;
+rtx set;
+/* If this is not a standard conditional jump, we can't parse it.  */
+if (!JUMP_P (jump)
+|| ! any_condjump_p (jump))
+return 0;
+set = pc_set (jump);
+cond = XEXP (SET_SRC (set), 0);
+/* If this branches to JUMP_LABEL when the condition is false, reverse
+the condition.  */
+reverse
+= GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
+&& XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (jump);
+return canonicalize_condition (jump, cond, reverse, earliest, NULL_RTX,
+				 allow_cc_mode, valid_at_insn_p);
+}
+/* Initialize the table NUM_SIGN_BIT_COPIES_IN_REP based on
+TARGET_MODE_REP_EXTENDED.
+Note that we assume that the property of
+TARGET_MODE_REP_EXTENDED(B, C) is sticky to the integral modes
+narrower than mode B.  I.e., if A is a mode narrower than B then in
+order to be able to operate on it in mode B, mode A needs to
+satisfy the requirements set by the representation of mode B.  */
+static void
+init_num_sign_bit_copies_in_rep (void)
+{
+enum machine_mode mode, in_mode;
+for (in_mode = GET_CLASS_NARROWEST_MODE (MODE_INT); in_mode != VOIDmode;
+in_mode = GET_MODE_WIDER_MODE (mode))
+for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != in_mode;
+	 mode = GET_MODE_WIDER_MODE (mode))
+{
+	enum machine_mode i;
+	/* Currently, it is assumed that TARGET_MODE_REP_EXTENDED
+	   extends to the next widest mode.  */
+	gcc_assert (targetm.mode_rep_extended (mode, in_mode) == UNKNOWN
+		    || GET_MODE_WIDER_MODE (mode) == in_mode);
+	/* We are in in_mode.  Count how many bits outside of mode
+	   have to be copies of the sign-bit.  */
+	for (i = mode; i != in_mode; i = GET_MODE_WIDER_MODE (i))
+	  {
+	    enum machine_mode wider = GET_MODE_WIDER_MODE (i);
+	    if (targetm.mode_rep_extended (i, wider) == SIGN_EXTEND
+		/* We can only check sign-bit copies starting from the
+		   top-bit.  In order to be able to check the bits we
+		   have already seen we pretend that subsequent bits
+		   have to be sign-bit copies too.  */
+		|| num_sign_bit_copies_in_rep [in_mode][mode])
+	      num_sign_bit_copies_in_rep [in_mode][mode]
+		+= GET_MODE_BITSIZE (wider) - GET_MODE_BITSIZE (i);
+	  }
+}
+}
+/* Suppose that truncation from the machine mode of X to MODE is not a
+no-op.  See if there is anything special about X so that we can
+assume it already contains a truncated value of MODE.  */
+bool
+truncated_to_mode (enum machine_mode mode, const_rtx x)
+{
+/* This register has already been used in MODE without explicit
+truncation.  */
+if (REG_P (x) && rtl_hooks.reg_truncated_to_mode (mode, x))
+return true;
+/* See if we already satisfy the requirements of MODE.  If yes we
+can just switch to MODE.  */
+if (num_sign_bit_copies_in_rep[GET_MODE (x)][mode]
+&& (num_sign_bit_copies (x, GET_MODE (x))
+	  >= num_sign_bit_copies_in_rep[GET_MODE (x)][mode] + 1))
+return true;
+return false;
+}
+/* Initialize non_rtx_starting_operands, which is used to speed up
+for_each_rtx.  */
+void
+init_rtlanal (void)
+{
+int i;
+for (i = 0; i < NUM_RTX_CODE; i++)
+{
+const char *format = GET_RTX_FORMAT (i);
+const char *first = strpbrk (format, "eEV");
+non_rtx_starting_operands[i] = first ? first - format : -1;
+}
+init_num_sign_bit_copies_in_rep ();
+}
+/* Check whether this is a constant pool constant.  */
+bool
+constant_pool_constant_p (rtx x)
+{
+x = avoid_constant_pool_reference (x);
+return GET_CODE (x) == CONST_DOUBLE;
+}

Mercurial > hg > CbC > CbC_gcc

comparison gcc/rtlanal.c @ 0:a06113de4d67