2009-04-27 Basile Starynkevitch <basile@starynkevitch.net>

	MERGED WITH TRUNK r146824::
	* gcc/basilys.h: all GTY goes before the identifiers.
	* gcc/basilys.c: removed errors.h include.
	* gcc/run-basilys.h: ditto.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/melt-branch@146839 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 42 insertions, 15 deletions

diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index a85858e17af..8982280fb2c 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -670,16 +670,6 @@ refs_may_alias_p_1 (tree ref1, tree ref2)
 		  || INDIRECT_REF_P (ref2)
 		  || TREE_CODE (ref2) == TARGET_MEM_REF));
 
-  /* Defer to TBAA if possible.  */
-  if (flag_strict_aliasing
-      && !alias_sets_conflict_p (get_alias_set (ref1), get_alias_set (ref2)))
-    return false;
-
-  /* If one reference is a TARGET_MEM_REF weird things are allowed.  */
-  if (TREE_CODE (ref1) == TARGET_MEM_REF
-      || TREE_CODE (ref2) == TARGET_MEM_REF)
-    return true;
-
   /* Decompose the references into their base objects and the access.  */
   base1 = get_ref_base_and_extent (ref1, &offset1, &size1, &max_size1);
   base2 = get_ref_base_and_extent (ref2, &offset2, &size2, &max_size2);
@@ -688,19 +678,37 @@ refs_may_alias_p_1 (tree ref1, tree ref2)
      *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59);
      which is seen as a struct copy.  */
   if (TREE_CODE (base1) == SSA_NAME
-      || CONSTANT_CLASS_P (base1)
       || TREE_CODE (base2) == SSA_NAME
-      || CONSTANT_CLASS_P (base2))
+      || is_gimple_min_invariant (base1)
+      || is_gimple_min_invariant (base2))
     return false;
 
+  /* Defer to simple offset based disambiguation if we have
+     references based on two decls.  Do this before defering to
+     TBAA to handle must-alias cases in conformance with the
+     GCC extension of allowing type-punning through unions.  */
   var1_p = SSA_VAR_P (base1);
   var2_p = SSA_VAR_P (base2);
-  ind1_p = INDIRECT_REF_P (base1);
-  ind2_p = INDIRECT_REF_P (base2);
   if (var1_p && var2_p)
     return decl_refs_may_alias_p (base1, offset1, max_size1,
 				  base2, offset2, max_size2);
-  else if (var1_p && ind2_p)
+
+  /* First defer to TBAA if possible.  */
+  if (flag_strict_aliasing
+      && !alias_sets_conflict_p (get_alias_set (ref1), get_alias_set (ref2)))
+    return false;
+
+  /* If one reference is a TARGET_MEM_REF weird things are allowed.  Still
+     TBAA disambiguation based on the access type is possible, so bail
+     out only after that check.  */
+  if (TREE_CODE (ref1) == TARGET_MEM_REF
+      || TREE_CODE (ref2) == TARGET_MEM_REF)
+    return true;
+
+  /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators.  */
+  ind1_p = INDIRECT_REF_P (base1);
+  ind2_p = INDIRECT_REF_P (base2);
+  if (var1_p && ind2_p)
     return indirect_ref_may_alias_decl_p (ref2, TREE_OPERAND (base2, 0),
 					  offset2, max_size2, -1,
 					  ref1, base1,
@@ -754,6 +762,14 @@ ref_maybe_used_by_call_p_1 (gimple call, tree ref)
       || !DECL_P (base))
     return true;
 
+  /* If the reference is based on a decl that is not aliased the call
+     cannot possibly use it.  */
+  if (DECL_P (base)
+      && !may_be_aliased (base)
+      /* But local statics can be used through recursion.  */
+      && !is_global_var (base))
+    goto process_args;
+
   /* Check if base is a global static variable that is not read
      by the function.  */
   if (TREE_CODE (base) == VAR_DECL
@@ -866,6 +882,17 @@ call_may_clobber_ref_p_1 (gimple call, tree ref)
       || CONSTANT_CLASS_P (base))
     return false;
 
+  /* If the reference is based on a decl that is not aliased the call
+     cannot possibly clobber it.  */
+  if (DECL_P (base)
+      && !may_be_aliased (base)
+      /* But local non-readonly statics can be modified through recursion
+         or the call may implement a threading barrier which we must
+	 treat as may-def.  */
+      && (TREE_READONLY (base)
+	  || !is_global_var (base)))
+    return false;
+
   /* Check if base is a global static variable that is not written
      by the function.  */
   if (TREE_CODE (base) == VAR_DECL