re PR tree-optimization/43879 (-fipa-pta causes various miscompilations)

2010-04-30  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/43879
	* tree-ssa-structalias.c (get_constraint_for_1): Properly
	handle non-zero initializers.

	* gcc.dg/torture/pr43879_1.c: New testcase.

From-SVN: r158924

gcc/ChangeLog

 2010-04-30  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/43879
+	* tree-ssa-structalias.c (get_constraint_for_1): Properly
+	handle non-zero initializers.
+
+2010-04-30  Richard Guenther  <rguenther@suse.de>
+
 	* builtins.c (fold_builtin_1): Delete free (0).
 
 2010-04-29  Jan HUbicka  <jh@suse.cz>

gcc/testsuite/ChangeLog

 2010-04-30  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/43879
+	* gcc.dg/torture/pr43879_1.c: New testcase.
+
+2010-04-30  Richard Guenther  <rguenther@suse.de>
+
 	* gcc.dg/tree-ssa/builtin-free.c: New testcase.
 
 2010-04-29  Fabien Chêne  <fabien.chene@gmail.com>

gcc/testsuite/gcc.dg/torture/pr43879_1.c

+/* { dg-do run } */
+/* { dg-options "-fipa-pta" } */
+/* { dg-additional-sources "pr43879_2.c" } */
+
+void bar(int c)
+{
+	static int x = 1;
+	if (c != x) __builtin_abort();
+	x--;
+}
+
+void baz(int *i)
+{
+	(*i)--;
+}
+
+struct TBL {
+	int (*p)(int *i);
+};
+extern struct TBL tbl;
+
+int main()
+{
+	int c = 1;
+	return tbl.p(&c);
+}
+

gcc/testsuite/gcc.dg/torture/pr43879_2.c

+struct TBL {
+	int (*p)(int *i);
+};
+
+extern void bar(int i);
+extern void baz(int *i);
+
+static int foo(int *i)
+{
+	bar(*i);
+	baz(i);
+	bar(*i);
+	return *i;
+}
+
+struct TBL tbl = { foo };
+

gcc/tree-ssa-structalias.c

@@ -3285,8 +3285,10 @@ get_constraint_for_1 (tree t, VEC (ce_s, heap) **results, bool address_p)
       && ((TREE_CODE (t) == INTEGER_CST
 	   && integer_zerop (t))
 	  /* The only valid CONSTRUCTORs in gimple with pointer typed
-	     elements are zero-initializer.  */
-	  || TREE_CODE (t) == CONSTRUCTOR))
+	     elements are zero-initializer.  But in IPA mode we also
+	     process global initializers, so verify at least.  */
+	  || (TREE_CODE (t) == CONSTRUCTOR
+	      && CONSTRUCTOR_NELTS (t) == 0)))
     {
       temp.var = nothing_id;
       temp.type = ADDRESSOF;