diff gcc/explow.c @ 67:f6334be47118

update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
author nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
date Tue, 22 Mar 2011 17:18:12 +0900
parents 77e2b8dfacca
children 04ced10e8804
line wrap: on
line diff
--- a/gcc/explow.c	Tue May 25 18:58:51 2010 +0900
+++ b/gcc/explow.c	Tue Mar 22 17:18:12 2011 +0900
@@ -1,6 +1,6 @@
 /* Subroutines for manipulating rtx's in semantically interesting ways.
    Copyright (C) 1987, 1991, 1994, 1995, 1996, 1997, 1998,
-   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
+   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -24,7 +24,7 @@
 #include "system.h"
 #include "coretypes.h"
 #include "tm.h"
-#include "toplev.h"
+#include "diagnostic-core.h"
 #include "rtl.h"
 #include "tree.h"
 #include "tm_p.h"
@@ -33,6 +33,7 @@
 #include "function.h"
 #include "expr.h"
 #include "optabs.h"
+#include "libfuncs.h"
 #include "hard-reg-set.h"
 #include "insn-config.h"
 #include "ggc.h"
@@ -42,7 +43,6 @@
 #include "output.h"
 
 static rtx break_out_memory_refs (rtx);
-static void emit_stack_probe (rtx);
 
 
 /* Truncate and perhaps sign-extend C as appropriate for MODE.  */
@@ -706,9 +706,13 @@
 	if (SYMBOL_REF_DECL (s) && DECL_P (SYMBOL_REF_DECL (s)))
 	  sa = DECL_ALIGN (SYMBOL_REF_DECL (s));
 
-	ca = exact_log2 (INTVAL (c) & -INTVAL (c)) * BITS_PER_UNIT;
-
-	align = MIN (sa, ca);
+	if (INTVAL (c) == 0)
+	  align = sa;
+	else
+	  {
+	    ca = ctz_hwi (INTVAL (c)) * BITS_PER_UNIT;
+	    align = MIN (sa, ca);
+	  }
       }
 
     if (align || (MEM_P (x) && MEM_POINTER (x)))
@@ -910,43 +914,57 @@
 static rtx
 round_push (rtx size)
 {
-  int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
+  rtx align_rtx, alignm1_rtx;
 
-  if (align == 1)
-    return size;
+  if (!SUPPORTS_STACK_ALIGNMENT
+      || crtl->preferred_stack_boundary == MAX_SUPPORTED_STACK_ALIGNMENT)
+    {
+      int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
+
+      if (align == 1)
+	return size;
 
-  if (CONST_INT_P (size))
-    {
-      HOST_WIDE_INT new_size = (INTVAL (size) + align - 1) / align * align;
+      if (CONST_INT_P (size))
+	{
+	  HOST_WIDE_INT new_size = (INTVAL (size) + align - 1) / align * align;
 
-      if (INTVAL (size) != new_size)
-	size = GEN_INT (new_size);
+	  if (INTVAL (size) != new_size)
+	    size = GEN_INT (new_size);
+	  return size;
+	}
+
+      align_rtx = GEN_INT (align);
+      alignm1_rtx = GEN_INT (align - 1);
     }
   else
     {
-      /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
-	 but we know it can't.  So add ourselves and then do
-	 TRUNC_DIV_EXPR.  */
-      size = expand_binop (Pmode, add_optab, size, GEN_INT (align - 1),
-			   NULL_RTX, 1, OPTAB_LIB_WIDEN);
-      size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, GEN_INT (align),
-			    NULL_RTX, 1);
-      size = expand_mult (Pmode, size, GEN_INT (align), NULL_RTX, 1);
+      /* If crtl->preferred_stack_boundary might still grow, use
+	 virtual_preferred_stack_boundary_rtx instead.  This will be
+	 substituted by the right value in vregs pass and optimized
+	 during combine.  */
+      align_rtx = virtual_preferred_stack_boundary_rtx;
+      alignm1_rtx = force_operand (plus_constant (align_rtx, -1), NULL_RTX);
     }
 
+  /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
+     but we know it can't.  So add ourselves and then do
+     TRUNC_DIV_EXPR.  */
+  size = expand_binop (Pmode, add_optab, size, alignm1_rtx,
+		       NULL_RTX, 1, OPTAB_LIB_WIDEN);
+  size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size, align_rtx,
+			NULL_RTX, 1);
+  size = expand_mult (Pmode, size, align_rtx, NULL_RTX, 1);
+
   return size;
 }
 
 /* Save the stack pointer for the purpose in SAVE_LEVEL.  PSAVE is a pointer
    to a previously-created save area.  If no save area has been allocated,
    this function will allocate one.  If a save area is specified, it
-   must be of the proper mode.
-
-   The insns are emitted after insn AFTER, if nonzero, otherwise the insns
-   are emitted at the current position.  */
+   must be of the proper mode.  */
 
 void
-emit_stack_save (enum save_level save_level, rtx *psave, rtx after)
+emit_stack_save (enum save_level save_level, rtx *psave)
 {
   rtx sa = *psave;
   /* The default is that we use a move insn and save in a Pmode object.  */
@@ -992,38 +1010,17 @@
 	}
     }
 
-  if (after)
-    {
-      rtx seq;
-
-      start_sequence ();
-      do_pending_stack_adjust ();
-      /* We must validize inside the sequence, to ensure that any instructions
-	 created by the validize call also get moved to the right place.  */
-      if (sa != 0)
-	sa = validize_mem (sa);
-      emit_insn (fcn (sa, stack_pointer_rtx));
-      seq = get_insns ();
-      end_sequence ();
-      emit_insn_after (seq, after);
-    }
-  else
-    {
-      do_pending_stack_adjust ();
-      if (sa != 0)
-	sa = validize_mem (sa);
-      emit_insn (fcn (sa, stack_pointer_rtx));
-    }
+  do_pending_stack_adjust ();
+  if (sa != 0)
+    sa = validize_mem (sa);
+  emit_insn (fcn (sa, stack_pointer_rtx));
 }
 
 /* Restore the stack pointer for the purpose in SAVE_LEVEL.  SA is the save
-   area made by emit_stack_save.  If it is zero, we have nothing to do.
-
-   Put any emitted insns after insn AFTER, if nonzero, otherwise at
-   current position.  */
+   area made by emit_stack_save.  If it is zero, we have nothing to do.  */
 
 void
-emit_stack_restore (enum save_level save_level, rtx sa, rtx after)
+emit_stack_restore (enum save_level save_level, rtx sa)
 {
   /* The default is that we use a move insn.  */
   rtx (*fcn) (rtx, rtx) = gen_move_insn;
@@ -1065,18 +1062,7 @@
 
   discard_pending_stack_adjust ();
 
-  if (after)
-    {
-      rtx seq;
-
-      start_sequence ();
-      emit_insn (fcn (stack_pointer_rtx, sa));
-      seq = get_insns ();
-      end_sequence ();
-      emit_insn_after (seq, after);
-    }
-  else
-    emit_insn (fcn (stack_pointer_rtx, sa));
+  emit_insn (fcn (stack_pointer_rtx, sa));
 }
 
 /* Invoke emit_stack_save on the nonlocal_goto_save_area for the current
@@ -1097,23 +1083,39 @@
 		   integer_one_node, NULL_TREE, NULL_TREE);
   r_save = expand_expr (t_save, NULL_RTX, VOIDmode, EXPAND_WRITE);
 
-  emit_stack_save (SAVE_NONLOCAL, &r_save, NULL_RTX);
+  emit_stack_save (SAVE_NONLOCAL, &r_save);
 }
 
 /* Return an rtx representing the address of an area of memory dynamically
-   pushed on the stack.  This region of memory is always aligned to
-   a multiple of BIGGEST_ALIGNMENT.
+   pushed on the stack.
 
    Any required stack pointer alignment is preserved.
 
    SIZE is an rtx representing the size of the area.
-   TARGET is a place in which the address can be placed.
+
+   SIZE_ALIGN is the alignment (in bits) that we know SIZE has.  This
+   parameter may be zero.  If so, a proper value will be extracted 
+   from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.
 
-   KNOWN_ALIGN is the alignment (in bits) that we know SIZE has.  */
+   REQUIRED_ALIGN is the alignment (in bits) required for the region
+   of memory.
+
+   If CANNOT_ACCUMULATE is set to TRUE, the caller guarantees that the
+   stack space allocated by the generated code cannot be added with itself
+   in the course of the execution of the function.  It is always safe to
+   pass FALSE here and the following criterion is sufficient in order to
+   pass TRUE: every path in the CFG that starts at the allocation point and
+   loops to it executes the associated deallocation code.  */
 
 rtx
-allocate_dynamic_stack_space (rtx size, rtx target, int known_align)
+allocate_dynamic_stack_space (rtx size, unsigned size_align,
+			      unsigned required_align, bool cannot_accumulate)
 {
+  HOST_WIDE_INT stack_usage_size = -1;
+  rtx final_label, final_target, target;
+  unsigned extra_align = 0;
+  bool must_align;
+
   /* If we're asking for zero bytes, it doesn't matter what we point
      to since we can't dereference it.  But return a reasonable
      address anyway.  */
@@ -1123,39 +1125,107 @@
   /* Otherwise, show we're calling alloca or equivalent.  */
   cfun->calls_alloca = 1;
 
+  /* If stack usage info is requested, look into the size we are passed.
+     We need to do so this early to avoid the obfuscation that may be
+     introduced later by the various alignment operations.  */
+  if (flag_stack_usage)
+    {
+      if (CONST_INT_P (size))
+	stack_usage_size = INTVAL (size);
+      else if (REG_P (size))
+        {
+	  /* Look into the last emitted insn and see if we can deduce
+	     something for the register.  */
+	  rtx insn, set, note;
+	  insn = get_last_insn ();
+	  if ((set = single_set (insn)) && rtx_equal_p (SET_DEST (set), size))
+	    {
+	      if (CONST_INT_P (SET_SRC (set)))
+		stack_usage_size = INTVAL (SET_SRC (set));
+	      else if ((note = find_reg_equal_equiv_note (insn))
+		       && CONST_INT_P (XEXP (note, 0)))
+		stack_usage_size = INTVAL (XEXP (note, 0));
+	    }
+	}
+
+      /* If the size is not constant, we can't say anything.  */
+      if (stack_usage_size == -1)
+	{
+	  current_function_has_unbounded_dynamic_stack_size = 1;
+	  stack_usage_size = 0;
+	}
+    }
+
   /* Ensure the size is in the proper mode.  */
   if (GET_MODE (size) != VOIDmode && GET_MODE (size) != Pmode)
     size = convert_to_mode (Pmode, size, 1);
 
+  /* Adjust SIZE_ALIGN, if needed.  */
+  if (CONST_INT_P (size))
+    {
+      unsigned HOST_WIDE_INT lsb;
+
+      lsb = INTVAL (size);
+      lsb &= -lsb;
+
+      /* Watch out for overflow truncating to "unsigned".  */
+      if (lsb > UINT_MAX / BITS_PER_UNIT)
+	size_align = 1u << (HOST_BITS_PER_INT - 1);
+      else
+	size_align = (unsigned)lsb * BITS_PER_UNIT;
+    }
+  else if (size_align < BITS_PER_UNIT)
+    size_align = BITS_PER_UNIT;
+
   /* We can't attempt to minimize alignment necessary, because we don't
      know the final value of preferred_stack_boundary yet while executing
      this code.  */
-  crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
+  if (crtl->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
+    crtl->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
 
   /* We will need to ensure that the address we return is aligned to
-     BIGGEST_ALIGNMENT.  If STACK_DYNAMIC_OFFSET is defined, we don't
+     REQUIRED_ALIGN.  If STACK_DYNAMIC_OFFSET is defined, we don't
      always know its final value at this point in the compilation (it
      might depend on the size of the outgoing parameter lists, for
      example), so we must align the value to be returned in that case.
      (Note that STACK_DYNAMIC_OFFSET will have a default nonzero value if
      STACK_POINTER_OFFSET or ACCUMULATE_OUTGOING_ARGS are defined).
      We must also do an alignment operation on the returned value if
-     the stack pointer alignment is less strict that BIGGEST_ALIGNMENT.
+     the stack pointer alignment is less strict than REQUIRED_ALIGN.
 
      If we have to align, we must leave space in SIZE for the hole
      that might result from the alignment operation.  */
 
+  must_align = (crtl->preferred_stack_boundary < required_align);
+  if (must_align)
+    {
+      if (required_align > PREFERRED_STACK_BOUNDARY)
+	extra_align = PREFERRED_STACK_BOUNDARY;
+      else if (required_align > STACK_BOUNDARY)
+	extra_align = STACK_BOUNDARY;
+      else
+	extra_align = BITS_PER_UNIT;
+    }
+
+  /* ??? STACK_POINTER_OFFSET is always defined now.  */
 #if defined (STACK_DYNAMIC_OFFSET) || defined (STACK_POINTER_OFFSET)
-#define MUST_ALIGN 1
-#else
-#define MUST_ALIGN (PREFERRED_STACK_BOUNDARY < BIGGEST_ALIGNMENT)
+  must_align = true;
+  extra_align = BITS_PER_UNIT;
 #endif
 
-  if (MUST_ALIGN)
-    size
-      = force_operand (plus_constant (size,
-				      BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
-		       NULL_RTX);
+  if (must_align)
+    {
+      unsigned extra = (required_align - extra_align) / BITS_PER_UNIT;
+
+      size = plus_constant (size, extra);
+      size = force_operand (size, NULL_RTX);
+
+      if (flag_stack_usage)
+	stack_usage_size += extra;
+
+      if (extra && size_align > extra_align)
+	size_align = extra_align;
+    }
 
 #ifdef SETJMP_VIA_SAVE_AREA
   /* If setjmp restores regs from a save area in the stack frame,
@@ -1169,32 +1239,7 @@
      would use reg notes to store the "optimized" size and fix things
      up later.  These days we know this information before we ever
      start building RTL so the reg notes are unnecessary.  */
-  if (!cfun->calls_setjmp)
-    {
-      int align = PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT;
-
-      /* ??? Code below assumes that the save area needs maximal
-	 alignment.  This constraint may be too strong.  */
-      gcc_assert (PREFERRED_STACK_BOUNDARY == BIGGEST_ALIGNMENT);
-
-      if (CONST_INT_P (size))
-	{
-	  HOST_WIDE_INT new_size = INTVAL (size) / align * align;
-
-	  if (INTVAL (size) != new_size)
-	    size = GEN_INT (new_size);
-	}
-      else
-	{
-	  /* Since we know overflow is not possible, we avoid using
-	     CEIL_DIV_EXPR and use TRUNC_DIV_EXPR instead.  */
-	  size = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, size,
-				GEN_INT (align), NULL_RTX, 1);
-	  size = expand_mult (Pmode, size,
-			      GEN_INT (align), NULL_RTX, 1);
-	}
-    }
-  else
+  if (cfun->calls_setjmp)
     {
       rtx dynamic_offset
 	= expand_binop (Pmode, sub_optab, virtual_stack_dynamic_rtx,
@@ -1202,6 +1247,15 @@
 
       size = expand_binop (Pmode, add_optab, size, dynamic_offset,
 			   NULL_RTX, 1, OPTAB_LIB_WIDEN);
+
+      /* The above dynamic offset cannot be computed statically at this
+	 point, but it will be possible to do so after RTL expansion is
+	 done.  Record how many times we will need to add it.  */
+      if (flag_stack_usage)
+	current_function_dynamic_alloc_count++;
+
+      /* ??? Can we infer a minimum of STACK_BOUNDARY here?  */
+      size_align = BITS_PER_UNIT;
     }
 #endif /* SETJMP_VIA_SAVE_AREA */
 
@@ -1218,13 +1272,89 @@
      insns.  Since this is an extremely rare event, we have no reliable
      way of knowing which systems have this problem.  So we avoid even
      momentarily mis-aligning the stack.  */
+  if (size_align % MAX_SUPPORTED_STACK_ALIGNMENT != 0)
+    {
+      size = round_push (size);
 
-  /* If we added a variable amount to SIZE,
-     we can no longer assume it is aligned.  */
-#if !defined (SETJMP_VIA_SAVE_AREA)
-  if (MUST_ALIGN || known_align % PREFERRED_STACK_BOUNDARY != 0)
+      if (flag_stack_usage)
+	{
+	  int align = crtl->preferred_stack_boundary / BITS_PER_UNIT;
+	  stack_usage_size = (stack_usage_size + align - 1) / align * align;
+	}
+    }
+
+  target = gen_reg_rtx (Pmode);
+
+  /* The size is supposed to be fully adjusted at this point so record it
+     if stack usage info is requested.  */
+  if (flag_stack_usage)
+    {
+      current_function_dynamic_stack_size += stack_usage_size;
+
+      /* ??? This is gross but the only safe stance in the absence
+	 of stack usage oriented flow analysis.  */
+      if (!cannot_accumulate)
+	current_function_has_unbounded_dynamic_stack_size = 1;
+    }
+
+  final_label = NULL_RTX;
+  final_target = NULL_RTX;
+
+  /* If we are splitting the stack, we need to ask the backend whether
+     there is enough room on the current stack.  If there isn't, or if
+     the backend doesn't know how to tell is, then we need to call a
+     function to allocate memory in some other way.  This memory will
+     be released when we release the current stack segment.  The
+     effect is that stack allocation becomes less efficient, but at
+     least it doesn't cause a stack overflow.  */
+  if (flag_split_stack)
+    {
+      rtx available_label, ask, space, func;
+
+      available_label = NULL_RTX;
+
+#ifdef HAVE_split_stack_space_check
+      if (HAVE_split_stack_space_check)
+	{
+	  available_label = gen_label_rtx ();
+
+	  /* This instruction will branch to AVAILABLE_LABEL if there
+	     are SIZE bytes available on the stack.  */
+	  emit_insn (gen_split_stack_space_check (size, available_label));
+	}
 #endif
-    size = round_push (size);
+
+      /* The __morestack_allocate_stack_space function will allocate
+	 memory using malloc.  If the alignment of the memory returned
+	 by malloc does not meet REQUIRED_ALIGN, we increase SIZE to
+	 make sure we allocate enough space.  */
+      if (MALLOC_ABI_ALIGNMENT >= required_align)
+	ask = size;
+      else
+	{
+	  ask = expand_binop (Pmode, add_optab, size,
+			      GEN_INT (required_align / BITS_PER_UNIT - 1),
+			      NULL_RTX, 1, OPTAB_LIB_WIDEN);
+	  must_align = true;
+	}
+
+      func = init_one_libfunc ("__morestack_allocate_stack_space");
+
+      space = emit_library_call_value (func, target, LCT_NORMAL, Pmode,
+				       1, ask, Pmode);
+
+      if (available_label == NULL_RTX)
+	return space;
+
+      final_target = gen_reg_rtx (Pmode);
+
+      emit_move_insn (final_target, space);
+
+      final_label = gen_label_rtx ();
+      emit_jump (final_label);
+
+      emit_label (available_label);
+    }
 
   do_pending_stack_adjust ();
 
@@ -1243,14 +1373,6 @@
   else if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK)
     probe_stack_range (STACK_CHECK_PROTECT, size);
 
-  /* Don't use a TARGET that isn't a pseudo or is the wrong mode.  */
-  if (target == 0 || !REG_P (target)
-      || REGNO (target) < FIRST_PSEUDO_REGISTER
-      || GET_MODE (target) != Pmode)
-    target = gen_reg_rtx (Pmode);
-
-  mark_reg_pointer (target, known_align);
-
   /* Perform the required allocation from the stack.  Some systems do
      this differently than simply incrementing/decrementing from the
      stack pointer, such as acquiring the space by calling malloc().  */
@@ -1276,6 +1398,8 @@
   else
 #endif
     {
+      int saved_stack_pointer_delta;
+
 #ifndef STACK_GROWS_DOWNWARD
       emit_move_insn (target, virtual_stack_dynamic_rtx);
 #endif
@@ -1306,32 +1430,49 @@
 	  emit_label (space_available);
 	}
 
+      saved_stack_pointer_delta = stack_pointer_delta;
       if (flag_stack_check && STACK_CHECK_MOVING_SP)
 	anti_adjust_stack_and_probe (size, false);
       else
 	anti_adjust_stack (size);
+      /* Even if size is constant, don't modify stack_pointer_delta.
+	 The constant size alloca should preserve
+	 crtl->preferred_stack_boundary alignment.  */
+      stack_pointer_delta = saved_stack_pointer_delta;
 
 #ifdef STACK_GROWS_DOWNWARD
       emit_move_insn (target, virtual_stack_dynamic_rtx);
 #endif
     }
 
-  if (MUST_ALIGN)
+  /* Finish up the split stack handling.  */
+  if (final_label != NULL_RTX)
+    {
+      gcc_assert (flag_split_stack);
+      emit_move_insn (final_target, target);
+      emit_label (final_label);
+      target = final_target;
+    }
+
+  if (must_align)
     {
       /* CEIL_DIV_EXPR needs to worry about the addition overflowing,
 	 but we know it can't.  So add ourselves and then do
 	 TRUNC_DIV_EXPR.  */
       target = expand_binop (Pmode, add_optab, target,
-			     GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT - 1),
+			     GEN_INT (required_align / BITS_PER_UNIT - 1),
 			     NULL_RTX, 1, OPTAB_LIB_WIDEN);
       target = expand_divmod (0, TRUNC_DIV_EXPR, Pmode, target,
-			      GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
+			      GEN_INT (required_align / BITS_PER_UNIT),
 			      NULL_RTX, 1);
       target = expand_mult (Pmode, target,
-			    GEN_INT (BIGGEST_ALIGNMENT / BITS_PER_UNIT),
+			    GEN_INT (required_align / BITS_PER_UNIT),
 			    NULL_RTX, 1);
     }
 
+  /* Now that we've committed to a return value, mark its alignment.  */
+  mark_reg_pointer (target, required_align);
+
   /* Record the new stack level for nonlocal gotos.  */
   if (cfun->nonlocal_goto_save_area != 0)
     update_nonlocal_goto_save_area ();
@@ -1346,14 +1487,15 @@
 static GTY(()) rtx stack_check_libfunc;
 
 void
-set_stack_check_libfunc (rtx libfunc)
+set_stack_check_libfunc (const char *libfunc_name)
 {
-  stack_check_libfunc = libfunc;
+  gcc_assert (stack_check_libfunc == NULL_RTX);
+  stack_check_libfunc = gen_rtx_SYMBOL_REF (Pmode, libfunc_name);
 }
 
 /* Emit one stack probe at ADDRESS, an address within the stack.  */
 
-static void
+void
 emit_stack_probe (rtx address)
 {
   rtx memref = gen_rtx_MEM (word_mode, address);
@@ -1519,7 +1661,7 @@
 	{
 	  rtx addr;
 
-	  if (GET_CODE (temp) == CONST_INT)
+	  if (CONST_INT_P (temp))
 	    {
 	      /* Use [base + disp} addressing mode if supported.  */
 	      HOST_WIDE_INT offset = INTVAL (temp);
@@ -1560,12 +1702,12 @@
 
   /* If we have a constant small number of probes to generate, that's the
      easy case.  */
-  if (GET_CODE (size) == CONST_INT && INTVAL (size) < 7 * PROBE_INTERVAL)
+  if (CONST_INT_P (size) && INTVAL (size) < 7 * PROBE_INTERVAL)
     {
       HOST_WIDE_INT isize = INTVAL (size), i;
       bool first_probe = true;
 
-      /* Adjust SP and probe to PROBE_INTERVAL + N * PROBE_INTERVAL for
+      /* Adjust SP and probe at PROBE_INTERVAL + N * PROBE_INTERVAL for
 	 values of N from 1 until it exceeds SIZE.  If only one probe is
 	 needed, this will not generate any code.  Then adjust and probe
 	 to PROBE_INTERVAL + SIZE.  */
@@ -1621,13 +1763,13 @@
 
       /* Step 3: the loop
 
-	  while (SP != LAST_ADDR)
-	    {
-	      SP = SP + PROBE_INTERVAL
-	      probe at SP
-	    }
+	 while (SP != LAST_ADDR)
+	   {
+	     SP = SP + PROBE_INTERVAL
+	     probe at SP
+	   }
 
-	 adjusts SP and probes to PROBE_INTERVAL + N * PROBE_INTERVAL for
+	 adjusts SP and probes at PROBE_INTERVAL + N * PROBE_INTERVAL for
 	 values of N from 1 until it is equal to ROUNDED_SIZE.  */
 
       emit_label (loop_lab);
@@ -1645,7 +1787,7 @@
       emit_label (end_lab);
 
 
-      /* Step 4: adjust SP and probe to PROBE_INTERVAL + SIZE if we cannot
+      /* Step 4: adjust SP and probe at PROBE_INTERVAL + SIZE if we cannot
 	 assert at compile-time that SIZE is equal to ROUNDED_SIZE.  */
 
       /* TEMP = SIZE - ROUNDED_SIZE.  */