CbC/CbC_gcc: gcc/alias.c comparison

comparison gcc/alias.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	b7f97abdc517
children	04ced10e8804

comparison

equal deleted inserted replaced

-:65488c3d617d
+:f6334be47118
 #include "regs.h"
 #include "hard-reg-set.h"
 #include "basic-block.h"
 #include "flags.h"
 #include "output.h"
-#include "toplev.h"
+#include "diagnostic-core.h"
 #include "cselib.h"
 #include "splay-tree.h"
 #include "ggc.h"
 #include "langhooks.h"
 #include "timevar.h"
 /* We preserve the copy of old array around to avoid amount of garbage
 produced.  About 8% of garbage produced were attributed to this
 array.  */
 static GTY((deletable)) VEC(rtx,gc) *old_reg_base_value;
-/* Static hunks of RTL used by the aliasing code; these are initialized
+#define static_reg_base_value \
-once per function to avoid unnecessary RTL allocations.  */
+(this_target_rtl->x_static_reg_base_value)
-static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER];
 #define REG_BASE_VALUE(X)				\
 (REGNO (X) < VEC_length (rtx, reg_base_value)		\
 ? VEC_index (rtx, reg_base_value, REGNO (X)) : 0)
 || TREE_CODE (base) == LABEL_DECL)
 return false;
 /* If this is a pointer dereference of a non-SSA_NAME punt.
 ???  We could replace it with a pointer to anything.  */
-if (INDIRECT_REF_P (base)
+if ((INDIRECT_REF_P (base)
+|| TREE_CODE (base) == MEM_REF)
 && TREE_CODE (TREE_OPERAND (base, 0)) != SSA_NAME)
+return false;
+if (TREE_CODE (base) == TARGET_MEM_REF
+&& TMR_BASE (base)
+&& TREE_CODE (TMR_BASE (base)) != SSA_NAME)
 return false;
 /* If this is a reference based on a partitioned decl replace the
 base with an INDIRECT_REF of the pointer representative we
 created during stack slot partitioning.  */
 && cfun->gimple_df->decls_to_pointers != NULL)
 {
 void *namep;
 namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers, base);
 if (namep)
-	{
+	ref->base = build_simple_mem_ref (*(tree *)namep);
-	  ref->base_alias_set = get_alias_set (base);
+}
-	  ref->base = build1 (INDIRECT_REF, TREE_TYPE (base), *(tree *)namep);
+else if (TREE_CODE (base) == TARGET_MEM_REF
-	}
+	   && TREE_CODE (TMR_BASE (base)) == ADDR_EXPR
+	   && TREE_CODE (TREE_OPERAND (TMR_BASE (base), 0)) == VAR_DECL
+	   && ! TREE_STATIC (TREE_OPERAND (TMR_BASE (base), 0))
+	   && cfun->gimple_df->decls_to_pointers != NULL)
+{
+void *namep;
+namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers,
+				    TREE_OPERAND (TMR_BASE (base), 0));
+if (namep)
+	ref->base = build_simple_mem_ref (*(tree *)namep);
 }
 ref->ref_alias_set = MEM_ALIAS_SET (mem);
 /* If MEM_OFFSET or MEM_SIZE are NULL we have to punt.
 if (!ao_ref_from_mem (&ref1, x)
 || !ao_ref_from_mem (&ref2, mem))
 return true;
-return refs_may_alias_p_1 (&ref1, &ref2, tbaa_p);
+return refs_may_alias_p_1 (&ref1, &ref2,
+			     tbaa_p
+			     && MEM_ALIAS_SET (x) != 0
+			     && MEM_ALIAS_SET (mem) != 0);
 }
 /* Returns a pointer to the alias set entry for ALIAS_SET, if there is
 such an entry, or NULL otherwise.  */
 /* The two alias sets are distinct and neither one is the
 child of the other.  Therefore, they cannot conflict.  */
 return 0;
 }
-static int
-walk_mems_2 (rtx *x, rtx mem)
-{
-if (MEM_P (*x))
-{
-if (alias_sets_conflict_p (MEM_ALIAS_SET(*x), MEM_ALIAS_SET(mem)))
-return 1;
-return -1;
-}
-return 0;
-}
-static int
-walk_mems_1 (rtx *x, rtx *pat)
-{
-if (MEM_P (*x))
-{
-/* Visit all MEMs in *PAT and check indepedence.  */
-if (for_each_rtx (pat, (rtx_function) walk_mems_2, *x))
-/* Indicate that dependence was determined and stop traversal.  */
-return 1;
-return -1;
-}
-return 0;
-}
-/* Return 1 if two specified instructions have mem expr with conflict alias sets*/
-bool
-insn_alias_sets_conflict_p (rtx insn1, rtx insn2)
-{
-/* For each pair of MEMs in INSN1 and INSN2 check their independence.  */
-return  for_each_rtx (&PATTERN (insn1), (rtx_function) walk_mems_1,
-			 &PATTERN (insn2));
-}
 /* Return 1 if the two specified alias sets will always conflict.  */
 int
 alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2)
 {
 aren't types.  */
 if (! TYPE_P (t))
 {
 tree inner;
-/* Remove any nops, then give the language a chance to do
+/* Give the language a chance to do something with this tree
-	 something with this tree before we look at it.  */
+	 before we look at it.  */
 STRIP_NOPS (t);
 set = lang_hooks.get_alias_set (t);
 if (set != -1)
 	return set;
-/* Retrieve the original memory reference if needed.  */
+/* Get the base object of the reference.  */
-if (TREE_CODE (t) == TARGET_MEM_REF)
-	t = TMR_ORIGINAL (t);
-/* First see if the actual object referenced is an INDIRECT_REF from a
-	 restrict-qualified pointer or a "void *".  */
 inner = t;
 while (handled_component_p (inner))
 	{
+	  /* If there is a VIEW_CONVERT_EXPR in the chain we cannot use
+	     the type of any component references that wrap it to
+	     determine the alias-set.  */
+	  if (TREE_CODE (inner) == VIEW_CONVERT_EXPR)
+	    t = TREE_OPERAND (inner, 0);
 	  inner = TREE_OPERAND (inner, 0);
-	  STRIP_NOPS (inner);
 	}
+/* Handle pointer dereferences here, they can override the
+	 alias-set.  */
 if (INDIRECT_REF_P (inner))
 	{
 	  set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0));
 	  if (set != -1)
 	    return set;
 	}
+else if (TREE_CODE (inner) == TARGET_MEM_REF)
+	return get_deref_alias_set (TMR_OFFSET (inner));
+else if (TREE_CODE (inner) == MEM_REF)
+	{
+	  set = get_deref_alias_set_1 (TREE_OPERAND (inner, 1));
+	  if (set != -1)
+	    return set;
+	}
+/* If the innermost reference is a MEM_REF that has a
+	 conversion embedded treat it like a VIEW_CONVERT_EXPR above,
+	 using the memory access type for determining the alias-set.  */
+if (TREE_CODE (inner) == MEM_REF
+	 && TYPE_MAIN_VARIANT (TREE_TYPE (inner))
+	    != TYPE_MAIN_VARIANT
+	       (TREE_TYPE (TREE_TYPE (TREE_OPERAND (inner, 1)))))
+return get_deref_alias_set (TREE_OPERAND (inner, 1));
 /* Otherwise, pick up the outermost object that we could have a pointer
 	 to, processing conversions as above.  */
 while (component_uses_parent_alias_set (t))
 	{
 set = lang_hooks.get_alias_set (t);
 if (set != -1)
 	return set;
 return 0;
 }
 t = TYPE_CANONICAL (t);
 /* Canonical types shouldn't form a tree nor should the canonical
 type require structural equality checks.  */
-gcc_assert (!TYPE_STRUCTURAL_EQUALITY_P (t) && TYPE_CANONICAL (t) == t);
+gcc_checking_assert (TYPE_CANONICAL (t) == t
+		       && !TYPE_STRUCTURAL_EQUALITY_P (t));
 /* If this is a type with a known alias set, return it.  */
 if (TYPE_ALIAS_SET_KNOWN_P (t))
 return TYPE_ALIAS_SET (t);
 return set;
 /* There are no objects of FUNCTION_TYPE, so there's no point in
 using up an alias set for them.  (There are, of course, pointers
 and references to functions, but that's different.)  */
-else if (TREE_CODE (t) == FUNCTION_TYPE
+else if (TREE_CODE (t) == FUNCTION_TYPE || TREE_CODE (t) == METHOD_TYPE)
-	   || TREE_CODE (t) == METHOD_TYPE)
 set = 0;
 /* Unless the language specifies otherwise, let vector types alias
 their components.  This avoids some nasty type punning issues in
 normal usage.  And indeed lets vectors be treated more like an
 character(kind=1) through a reference to a character(kind=1)[1:1].
 Or consider if we want to assign integer(kind=4)[0:D.1387] and
 integer(kind=4)[4] the same alias set or not.
 Just be pragmatic here and make sure the array and its element
 type get the same alias set assigned.  */
-else if (TREE_CODE (t) == ARRAY_TYPE
+else if (TREE_CODE (t) == ARRAY_TYPE && !TYPE_NONALIASED_COMPONENT (t))
-	   && !TYPE_NONALIASED_COMPONENT (t))
 set = get_alias_set (TREE_TYPE (t));
+/* From the former common C and C++ langhook implementation:
+Unfortunately, there is no canonical form of a pointer type.
+In particular, if we have `typedef int I', then `int *', and
+`I *' are different types.  So, we have to pick a canonical
+representative.  We do this below.
+Technically, this approach is actually more conservative that
+it needs to be.  In particular, `const int *' and `int *'
+should be in different alias sets, according to the C and C++
+standard, since their types are not the same, and so,
+technically, an `int **' and `const int **' cannot point at
+the same thing.
+But, the standard is wrong.  In particular, this code is
+legal C++:
+int *ip;
+int **ipp = &ip;
+const int* const* cipp = ipp;
+And, it doesn't make sense for that to be legal unless you
+can dereference IPP and CIPP.  So, we ignore cv-qualifiers on
+the pointed-to types.  This issue has been reported to the
+C++ committee.
+In addition to the above canonicalization issue, with LTO
+we should also canonicalize `T (*)[]' to `T *' avoiding
+alias issues with pointer-to element types and pointer-to
+array types.
+Likewise we need to deal with the situation of incomplete
+pointed-to types and make `*(struct X **)&a' and
+`*(struct X {} **)&a' alias.  Otherwise we will have to
+guarantee that all pointer-to incomplete type variants
+will be replaced by pointer-to complete type variants if
+they are available.
+With LTO the convenient situation of using `void *' to
+access and store any pointer type will also become
+more apparent (and `void *' is just another pointer-to
+incomplete type).  Assigning alias-set zero to `void *'
+and all pointer-to incomplete types is a not appealing
+solution.  Assigning an effective alias-set zero only
+affecting pointers might be - by recording proper subset
+relationships of all pointer alias-sets.
+Pointer-to function types are another grey area which
+needs caution.  Globbing them all into one alias-set
+or the above effective zero set would work.
+For now just assign the same alias-set to all pointers.
+That's simple and avoids all the above problems.  */
+else if (POINTER_TYPE_P (t)
+	   && t != ptr_type_node)
+return get_alias_set (ptr_type_node);
+/* Otherwise make a new alias set for this type.  */
 else
-/* Otherwise make a new alias set for this type.  */
 set = new_alias_set ();
 TYPE_ALIAS_SET (t) = set;
-/* If this is an aggregate type, we must record any component aliasing
+/* If this is an aggregate type or a complex type, we must record any
-information.  */
+component aliasing information.  */
 if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE)
 record_component_aliases (t);
 return set;
 }
 superset_entry = get_alias_set_entry (superset);
 if (superset_entry == 0)
 {
 /* Create an entry for the SUPERSET, so that we have a place to
 	 attach the SUBSET.  */
-superset_entry = GGC_NEW (struct alias_set_entry_d);
+superset_entry = ggc_alloc_cleared_alias_set_entry_d ();
 superset_entry->alias_set = superset;
 superset_entry->children
-	= splay_tree_new_ggc (splay_tree_compare_ints);
+	= splay_tree_new_ggc (splay_tree_compare_ints,
+			      ggc_alloc_splay_tree_scalar_scalar_splay_tree_s,
+			      ggc_alloc_splay_tree_scalar_scalar_splay_tree_node_s);
 superset_entry->has_zero_child = 0;
 VEC_replace (alias_set_entry, alias_sets, superset, superset_entry);
 }
 if (subset == 0)
 	  for (binfo = TYPE_BINFO (type), i = 0;
 	       BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
 	    record_alias_subset (superset,
 				 get_alias_set (BINFO_TYPE (base_binfo)));
 	}
-for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field))
+for (field = TYPE_FIELDS (type); field != 0; field = DECL_CHAIN (field))
 	if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field))
 	  record_alias_subset (superset, get_alias_set (TREE_TYPE (field)));
 break;
 case COMPLEX_TYPE:
 if (!REG_P (dest))
 return;
 regno = REGNO (dest);
-gcc_assert (regno < VEC_length (rtx, reg_base_value));
+gcc_checking_assert (regno < VEC_length (rtx, reg_base_value));
 /* If this spans multiple hard registers, then we must indicate that every
 register has an unusable value.  */
 if (regno < FIRST_PSEUDO_REGISTER)
 n = hard_regno_nregs[regno][GET_MODE (dest)];
 else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno])
 	   && ! reg_seen[regno] && new_reg_base_value[regno] == 0)
 new_reg_base_value[regno] = find_base_value (src);
 reg_seen[regno] = 1;
+}
+/* Return REG_BASE_VALUE for REGNO.  Selective scheduler uses this to avoid
+using hard registers with non-null REG_BASE_VALUE for renaming.  */
+rtx
+get_reg_base_value (unsigned int regno)
+{
+return VEC_index (rtx, reg_base_value, regno);
 }
 /* If a value is known for REGNO, return it.  */
 rtx
 return GEN_INT (ioffset);
 }
 /* Return nonzero if we can determine the exprs corresponding to memrefs
-X and Y and they do not overlap.  */
+X and Y and they do not overlap.
+If LOOP_VARIANT is set, skip offset-based disambiguation */
 int
-nonoverlapping_memrefs_p (const_rtx x, const_rtx y)
+nonoverlapping_memrefs_p (const_rtx x, const_rtx y, bool loop_invariant)
 {
 tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y);
 rtx rtlx, rtly;
 rtx basex, basey;
 rtx moffsetx, moffsety;
 	    || (CONSTANT_P (basex) && REG_P (basey)
 		&& REGNO_PTR_FRAME_P (REGNO (basey)))
 	    || (CONSTANT_P (basey) && REG_P (basex)
 		&& REGNO_PTR_FRAME_P (REGNO (basex))));
+/* Offset based disambiguation not appropriate for loop invariant */
+if (loop_invariant)
+return 0;
 sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx))
 	   : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx))
 	   : -1);
 sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly))
 	   : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) :
 /* If we don't know the size of the lower-offset value, we can't tell
 if they conflict.  Otherwise, we do the test.  */
 return sizex >= 0 && offsety >= offsetx + sizex;
 }
-/* True dependence: X is read after store in MEM takes place.  */
+/* Helper for true_dependence and canon_true_dependence.
+Checks for true dependence: X is read after store in MEM takes place.
-int
-true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x,
+VARIES is the function that should be used as rtx_varies function.
-		 bool (*varies) (const_rtx, bool))
-{
+If MEM_CANONICALIZED is FALSE, then X_ADDR and MEM_ADDR should be
-rtx x_addr, mem_addr;
+NULL_RTX, and the canonical addresses of MEM and X are both computed
+here.  If MEM_CANONICALIZED, then MEM must be already canonicalized.
+If X_ADDR is non-NULL, it is used in preference of XEXP (x, 0).
+Returns 1 if there is a true dependence, 0 otherwise.  */
+static int
+true_dependence_1 (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr,
+		   const_rtx x, rtx x_addr, bool (*varies) (const_rtx, bool),
+		   bool mem_canonicalized)
+{
 rtx base;
 int ret;
+gcc_checking_assert (mem_canonicalized ? (mem_addr != NULL_RTX)
+		       : (mem_addr == NULL_RTX && x_addr == NULL_RTX));
 if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
 return 1;
 /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
 potentially overlap), we cannot easily tell from the addresses
 whether the references overlap.  */
 if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
 return 1;
-if (mem_mode == VOIDmode)
+if (! mem_addr)
-mem_mode = GET_MODE (mem);
+{
+mem_addr = XEXP (mem, 0);
+if (mem_mode == VOIDmode)
+	mem_mode = GET_MODE (mem);
+}
+if (! x_addr)
+{
+x_addr = XEXP (x, 0);
+if (!((GET_CODE (x_addr) == VALUE
+	     && GET_CODE (mem_addr) != VALUE
+	     && reg_mentioned_p (x_addr, mem_addr))
+	    || (GET_CODE (x_addr) != VALUE
+		&& GET_CODE (mem_addr) == VALUE
+		&& reg_mentioned_p (mem_addr, x_addr))))
+	{
+	  x_addr = get_addr (x_addr);
+	  if (! mem_canonicalized)
+	    mem_addr = get_addr (mem_addr);
+	}
+}
+base = find_base_term (x_addr);
+if (base && (GET_CODE (base) == LABEL_REF
+	       || (GET_CODE (base) == SYMBOL_REF
+		   && CONSTANT_POOL_ADDRESS_P (base))))
+return 0;
+if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
+return 0;
+x_addr = canon_rtx (x_addr);
+if (!mem_canonicalized)
+mem_addr = canon_rtx (mem_addr);
+if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
+				 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
+return ret;
+if (DIFFERENT_ALIAS_SETS_P (x, mem))
+return 0;
+if (nonoverlapping_memrefs_p (mem, x, false))
+return 0;
+if (aliases_everything_p (x))
+return 1;
+/* We cannot use aliases_everything_p to test MEM, since we must look
+at MEM_ADDR, rather than XEXP (mem, 0).  */
+if (GET_CODE (mem_addr) == AND)
+return 1;
+/* ??? In true_dependence we also allow BLKmode to alias anything.  Why
+don't we do this in anti_dependence and output_dependence?  */
+if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
+return 1;
+if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies))
+return 0;
+return rtx_refs_may_alias_p (x, mem, true);
+}
+/* True dependence: X is read after store in MEM takes place.  */
+int
+true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x,
+		 bool (*varies) (const_rtx, bool))
+{
+return true_dependence_1 (mem, mem_mode, NULL_RTX,
+			    x, NULL_RTX, varies,
+			    /*mem_canonicalized=*/false);
+}
+/* Canonical true dependence: X is read after store in MEM takes place.
+Variant of true_dependence which assumes MEM has already been
+canonicalized (hence we no longer do that here).
+The mem_addr argument has been added, since true_dependence_1 computed
+this value prior to canonicalizing.  */
+int
+canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr,
+		       const_rtx x, rtx x_addr, bool (*varies) (const_rtx, bool))
+{
+return true_dependence_1 (mem, mem_mode, mem_addr,
+			    x, x_addr, varies,
+			    /*mem_canonicalized=*/true);
+}
+/* Returns nonzero if a write to X might alias a previous read from
+(or, if WRITEP is nonzero, a write to) MEM.  */
+static int
+write_dependence_p (const_rtx mem, const_rtx x, int writep)
+{
+rtx x_addr, mem_addr;
+const_rtx fixed_scalar;
+rtx base;
+int ret;
+if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
+return 1;
+/* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
+This is used in epilogue deallocation functions.  */
+if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
+return 1;
+if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
+return 1;
+if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
+|| MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
+return 1;
+/* A read from read-only memory can't conflict with read-write memory.  */
+if (!writep && MEM_READONLY_P (mem))
+return 0;
+/* If we have MEMs refering to different address spaces (which can
+potentially overlap), we cannot easily tell from the addresses
+whether the references overlap.  */
+if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
+return 1;
 x_addr = XEXP (x, 0);
 mem_addr = XEXP (mem, 0);
 if (!((GET_CODE (x_addr) == VALUE
 	 && GET_CODE (mem_addr) != VALUE
 {
 x_addr = get_addr (x_addr);
 mem_addr = get_addr (mem_addr);
 }
-base = find_base_term (x_addr);
+if (! writep)
-if (base && (GET_CODE (base) == LABEL_REF
+{
-	       || (GET_CODE (base) == SYMBOL_REF
+base = find_base_term (mem_addr);
-		   && CONSTANT_POOL_ADDRESS_P (base))))
+if (base && (GET_CODE (base) == LABEL_REF
-return 0;
+		   || (GET_CODE (base) == SYMBOL_REF
+		       && CONSTANT_POOL_ADDRESS_P (base))))
-if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
+	return 0;
+}
+if (! base_alias_check (x_addr, mem_addr, GET_MODE (x),
+			  GET_MODE (mem)))
 return 0;
 x_addr = canon_rtx (x_addr);
 mem_addr = canon_rtx (mem_addr);
-if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
+if ((ret = memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr,
 				 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
 return ret;
-if (DIFFERENT_ALIAS_SETS_P (x, mem))
+if (nonoverlapping_memrefs_p (x, mem, false))
 return 0;
-if (nonoverlapping_memrefs_p (mem, x))
+fixed_scalar
+= fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr,
+					 rtx_addr_varies_p);
+if ((fixed_scalar == mem && !aliases_everything_p (x))
+|| (fixed_scalar == x && !aliases_everything_p (mem)))
 return 0;
-if (aliases_everything_p (x))
+return rtx_refs_may_alias_p (x, mem, false);
-return 1;
+}
-/* We cannot use aliases_everything_p to test MEM, since we must look
+/* Anti dependence: X is written after read in MEM takes place.  */
-at MEM_MODE, rather than GET_MODE (MEM).  */
-if (mem_mode == QImode || GET_CODE (mem_addr) == AND)
-return 1;
-/* In true_dependence we also allow BLKmode to alias anything.  Why
-don't we do this in anti_dependence and output_dependence?  */
-if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
-return 1;
-if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies))
-return 0;
-return rtx_refs_may_alias_p (x, mem, true);
-}
-/* Canonical true dependence: X is read after store in MEM takes place.
-Variant of true_dependence which assumes MEM has already been
-canonicalized (hence we no longer do that here).
-The mem_addr argument has been added, since true_dependence computed
-this value prior to canonicalizing.
-If x_addr is non-NULL, it is used in preference of XEXP (x, 0).  */
 int
-canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr,
+anti_dependence (const_rtx mem, const_rtx x)
-		       const_rtx x, rtx x_addr, bool (*varies) (const_rtx, bool))
+{
-{
+return write_dependence_p (mem, x, /*writep=*/0);
-int ret;
+}
+/* Output dependence: X is written after store in MEM takes place.  */
+int
+output_dependence (const_rtx mem, const_rtx x)
+{
+return write_dependence_p (mem, x, /*writep=*/1);
+}
+/* Check whether X may be aliased with MEM.  Don't do offset-based
+memory disambiguation & TBAA.  */
+int
+may_alias_p (const_rtx mem, const_rtx x)
+{
+rtx x_addr, mem_addr;
 if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
 return 1;
-/* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
+/* ??? In true_dependence we also allow BLKmode to alias anything. */
-This is used in epilogue deallocation functions.  */
+if (GET_MODE (mem) == BLKmode || GET_MODE (x) == BLKmode)
-if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
+return 1;
-return 1;
-if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
-return 1;
 if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
 || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
 return 1;
 /* Read-only memory is by definition never modified, and therefore can't
 conflict with anything.  We don't expect to find read-only set on MEM,
 but stupid user tricks can produce them, so don't die.  */
 if (MEM_READONLY_P (x))
-return 0;
-/* If we have MEMs refering to different address spaces (which can
-potentially overlap), we cannot easily tell from the addresses
-whether the references overlap.  */
-if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
-return 1;
-if (! x_addr)
-{
-x_addr = XEXP (x, 0);
-if (!((GET_CODE (x_addr) == VALUE
-	     && GET_CODE (mem_addr) != VALUE
-	     && reg_mentioned_p (x_addr, mem_addr))
-	    || (GET_CODE (x_addr) != VALUE
-		&& GET_CODE (mem_addr) == VALUE
-		&& reg_mentioned_p (mem_addr, x_addr))))
-	x_addr = get_addr (x_addr);
-}
-if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
-return 0;
-x_addr = canon_rtx (x_addr);
-if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
-				 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
-return ret;
-if (DIFFERENT_ALIAS_SETS_P (x, mem))
-return 0;
-if (nonoverlapping_memrefs_p (x, mem))
-return 0;
-if (aliases_everything_p (x))
-return 1;
-/* We cannot use aliases_everything_p to test MEM, since we must look
-at MEM_MODE, rather than GET_MODE (MEM).  */
-if (mem_mode == QImode || GET_CODE (mem_addr) == AND)
-return 1;
-/* In true_dependence we also allow BLKmode to alias anything.  Why
-don't we do this in anti_dependence and output_dependence?  */
-if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
-return 1;
-if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies))
-return 0;
-return rtx_refs_may_alias_p (x, mem, true);
-}
-/* Returns nonzero if a write to X might alias a previous read from
-(or, if WRITEP is nonzero, a write to) MEM.  */
-static int
-write_dependence_p (const_rtx mem, const_rtx x, int writep)
-{
-rtx x_addr, mem_addr;
-const_rtx fixed_scalar;
-rtx base;
-int ret;
-if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
-return 1;
-/* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
-This is used in epilogue deallocation functions.  */
-if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
-return 1;
-if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
-return 1;
-if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
-|| MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
-return 1;
-/* A read from read-only memory can't conflict with read-write memory.  */
-if (!writep && MEM_READONLY_P (mem))
 return 0;
 /* If we have MEMs refering to different address spaces (which can
 potentially overlap), we cannot easily tell from the addresses
 whether the references overlap.  */
 {
 x_addr = get_addr (x_addr);
 mem_addr = get_addr (mem_addr);
 }
-if (! writep)
+if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), GET_MODE (mem_addr)))
-{
-base = find_base_term (mem_addr);
-if (base && (GET_CODE (base) == LABEL_REF
-		   || (GET_CODE (base) == SYMBOL_REF
-		       && CONSTANT_POOL_ADDRESS_P (base))))
-	return 0;
-}
-if (! base_alias_check (x_addr, mem_addr, GET_MODE (x),
-			  GET_MODE (mem)))
 return 0;
 x_addr = canon_rtx (x_addr);
 mem_addr = canon_rtx (mem_addr);
-if ((ret = memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr,
+if (nonoverlapping_memrefs_p (mem, x, true))
-				 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
-return ret;
-if (nonoverlapping_memrefs_p (x, mem))
 return 0;
-fixed_scalar
+if (aliases_everything_p (x))
-= fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr,
+return 1;
-					 rtx_addr_varies_p);
+/* We cannot use aliases_everything_p to test MEM, since we must look
-if ((fixed_scalar == mem && !aliases_everything_p (x))
+at MEM_ADDR, rather than XEXP (mem, 0).  */
-|| (fixed_scalar == x && !aliases_everything_p (mem)))
+if (GET_CODE (mem_addr) == AND)
+return 1;
+if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr,
+rtx_addr_varies_p))
 return 0;
+/* TBAA not valid for loop_invarint */
 return rtx_refs_may_alias_p (x, mem, false);
 }
-/* Anti dependence: X is written after read in MEM takes place.  */
-int
-anti_dependence (const_rtx mem, const_rtx x)
-{
-return write_dependence_p (mem, x, /*writep=*/0);
-}
-/* Output dependence: X is written after store in MEM takes place.  */
-int
-output_dependence (const_rtx mem, const_rtx x)
-{
-return write_dependence_p (mem, x, /*writep=*/1);
-}
 void
 init_alias_target (void)
 {
 int i;
 = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx);
 static_reg_base_value[ARG_POINTER_REGNUM]
 = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx);
 static_reg_base_value[FRAME_POINTER_REGNUM]
 = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx);
-#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
+#if !HARD_FRAME_POINTER_IS_FRAME_POINTER
 static_reg_base_value[HARD_FRAME_POINTER_REGNUM]
 = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx);
 #endif
 }
 rtx insn;
 timevar_push (TV_ALIAS_ANALYSIS);
 reg_known_value_size = maxreg - FIRST_PSEUDO_REGISTER;
-reg_known_value = GGC_CNEWVEC (rtx, reg_known_value_size);
+reg_known_value = ggc_alloc_cleared_vec_rtx (reg_known_value_size);
 reg_known_equiv_p = XCNEWVEC (bool, reg_known_value_size);
 /* If we have memory allocated from the previous run, use it.  */
 if (old_reg_base_value)
 reg_base_value = old_reg_base_value;
 free (reg_seen);
 reg_seen = 0;
 timevar_pop (TV_ALIAS_ANALYSIS);
 }
+/* Equate REG_BASE_VALUE (reg1) to REG_BASE_VALUE (reg2).
+Special API for var-tracking pass purposes.  */
+void
+vt_equate_reg_base_value (const_rtx reg1, const_rtx reg2)
+{
+VEC_replace (rtx, reg_base_value, REGNO (reg1), REG_BASE_VALUE (reg2));
+}
 void
 end_alias_analysis (void)
 {
 old_reg_base_value = reg_base_value;
 ggc_free (reg_known_value);

Mercurial > hg > CbC > CbC_gcc

comparison gcc/alias.c @ 67:f6334be47118