2008-04-23 Richard Guenther <rguenther@suse.de>

	PR tree-optimization/27799
	PR tree-optimization/32921
	PR tree-optimization/32624
	* tree-ssa-structalias.c (merge_smts_into): Only merge the
	SMTs aliases and the tag itself into the solution.
	* tree-ssa-alias.c (compute_flow_sensitive_aliasing): Do not
	merge the points-to solution back into the SMT aliases.
	(may_alias_p): Use alias_set_subset_of instead of
	aliases_conflict_p.  A pointer which points to
	memory with alias set zero may access any variable.

	* gcc.dg/tree-ssa/pr27799.c: New testcase.
	* gcc.dg/tree-ssa/20030807-7.c: Remove xfail, scan vrp dump.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@134598 138bc75d-0d04-0410-961f-82ee72b054a4

6 files changed, 65 insertions, 34 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a774a43341a..4fdb84928c5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,18 @@
 2008-04-23  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/27799
+	PR tree-optimization/32921
+	PR tree-optimization/32624
+	* tree-ssa-structalias.c (merge_smts_into): Only merge the
+	SMTs aliases and the tag itself into the solution.
+	* tree-ssa-alias.c (compute_flow_sensitive_aliasing): Do not
+	merge the points-to solution back into the SMT aliases.
+	(may_alias_p): Use alias_set_subset_of instead of
+	aliases_conflict_p.  A pointer which points to
+	memory with alias set zero may access any variable.
+
+2008-04-23  Richard Guenther  <rguenther@suse.de>
+
 	* alias.c (alias_set_subset_of): Correctly handle asking
 	if zero is a subset of an alias set with zero child.
 	* tree-ssa-alias.c (have_common_aliases_p): Simplify logic.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d5828e87085..82b6042f877 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,13 @@
 2008-04-23  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/27799
+	PR tree-optimization/32921
+	PR tree-optimization/32624
+	* gcc.dg/tree-ssa/pr27799.c: New testcase.
+	* gcc.dg/tree-ssa/20030807-7.c: Remove xfail, scan vrp dump.
+
+2008-04-23  Richard Guenther  <rguenther@suse.de>
+
 	PR middle-end/36021
 	* gcc.dg/attr-alloc_size-2.c: New testcase.
 
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/20030807-7.c b/gcc/testsuite/gcc.dg/tree-ssa/20030807-7.c
index 253c27ac4f7..f9f5fb798ef 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/20030807-7.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/20030807-7.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-dom3" } */
+/* { dg-options "-O2 -fdump-tree-vrp1" } */
   
 extern void abort (void);
 
@@ -32,7 +32,6 @@ simplify_condition (cond_p)
   c_simplify_stmt (&decl);
 }
 
-/* There should be exactly one IF conditional.  TBAA is not able to 
-   determine that 'decl' and 'cond' can't alias.  */
-/* { dg-final { scan-tree-dump-times "if " 1 "dom3" { xfail *-*-* } } } */
-/* { dg-final { cleanup-tree-dump "dom3" } } */
+/* There should be exactly one IF conditional.  */
+/* { dg-final { scan-tree-dump-times "if " 1 "vrp1" } } */
+/* { dg-final { cleanup-tree-dump "vrp1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr27799.c b/gcc/testsuite/gcc.dg/tree-ssa/pr27799.c
new file mode 100644
index 00000000000..de09a40e08b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr27799.c
@@ -0,0 +1,26 @@
+/* { dg-do link } */
+/* { dg-options "-O2" } */
+
+struct X { double m; int x; };
+struct Y { int y; short d; };
+struct YY { int y; short d; char c; };
+
+extern void link_error (void);
+
+int foo(struct X *x,  struct Y *y)
+{
+  x->x =  0;
+  y->y =  1;
+  if (x->x != 0)
+    link_error ();
+}
+
+int foo_no(struct X *x,  struct YY *y)
+{
+  x->x =  0;
+  y->y =  1;
+  if (x->x != 0)
+    link_error ();
+}
+
+int main() {}
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index eb57010bdda..ecc827ab9e9 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -2354,7 +2354,6 @@ compute_flow_sensitive_aliasing (struct alias_info *ai)
   for (i = 0; VEC_iterate (tree, ai->processed_ptrs, i, ptr); i++)
     {
       struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
-      tree tag = symbol_mem_tag (SSA_NAME_VAR (ptr));
 
       /* Set up aliasing information for PTR's name memory tag (if it has
 	 one).  Note that only pointers that have been dereferenced will
@@ -2362,18 +2361,7 @@ compute_flow_sensitive_aliasing (struct alias_info *ai)
       if (pi->name_mem_tag && pi->pt_vars)
 	{
 	  if (!bitmap_empty_p (pi->pt_vars))
-	    {
-	      union_alias_set_into (pi->name_mem_tag, pi->pt_vars);
-	      union_alias_set_into (tag, pi->pt_vars);
-	      bitmap_clear_bit (MTAG_ALIASES (tag), DECL_UID (tag));
-	    
-	      /* It may be the case that this the tag uid was the only
-		 bit we had set in the aliases list, and in this case,
-		 we don't want to keep an empty bitmap, as this
-		 asserts in tree-ssa-operands.c .  */
-	      if (bitmap_empty_p (MTAG_ALIASES (tag)))
-		BITMAP_FREE (MTAG_ALIASES (tag));
-	    }
+	    union_alias_set_into (pi->name_mem_tag, pi->pt_vars);
 	}
     }
   timevar_pop (TV_FLOW_SENSITIVE);
@@ -2860,8 +2848,19 @@ may_alias_p (tree ptr, alias_set_type mem_alias_set,
     {
       alias_stats.tbaa_queries++;
 
+      /* If the pointed to memory has alias set zero or the pointer
+	 is ref-all, the MEM can alias VAR.  */
+      if (mem_alias_set == 0
+	  || PTR_IS_REF_ALL (ptr))
+	{
+	  alias_stats.alias_mayalias++;
+	  alias_stats.tbaa_resolved++;
+	  return true;
+	}
+
       /* If the alias sets don't conflict then MEM cannot alias VAR.  */
-      if (!alias_sets_conflict_p (mem_alias_set, var_alias_set))
+      if (mem_alias_set != var_alias_set
+	  && !alias_set_subset_of (mem_alias_set, var_alias_set))
 	{
 	  alias_stats.alias_noalias++;
 	  alias_stats.tbaa_resolved++;
diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index 5323a2ba976..9a8afb70a2b 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -4861,8 +4861,6 @@ set_used_smts (void)
 static void
 merge_smts_into (tree p, bitmap solution)
 {
-  unsigned int i;
-  bitmap_iterator bi;
   tree smt;
   bitmap aliases;
   tree var = p;
@@ -4873,20 +4871,8 @@ merge_smts_into (tree p, bitmap solution)
   smt = var_ann (var)->symbol_mem_tag;
   if (smt)
     {
-      alias_set_type smtset = get_alias_set (TREE_TYPE (smt));
-
-      /* Need to set the SMT subsets first before this
-	 will work properly.  */
+      /* The smt itself isn't included in its aliases.  */
       bitmap_set_bit (solution, DECL_UID (smt));
-      EXECUTE_IF_SET_IN_BITMAP (used_smts, 0, i, bi)
-	{
-	  tree newsmt = referenced_var (i);
-	  tree newsmttype = TREE_TYPE (newsmt);
-
-	  if (alias_set_subset_of (get_alias_set (newsmttype),
-				   smtset))
-	    bitmap_set_bit (solution, i);
-	}
 
       aliases = MTAG_ALIASES (smt);
       if (aliases)