re PR middle-end/57287 (Bogus uninitialized warning with abnormal control flow)

2013-08-29  Richard Biener  <rguenther@suse.de>

	PR middle-end/57287
	* tree-ssa-copy.c (may_propagate_copy): Allow propagating
	of default defs that appear in abnormal PHI nodes.

	* gcc.dg/pr57287-2.c: New testcase.

From-SVN: r202069

gcc/ChangeLog

 2013-08-29  Richard Biener  <rguenther@suse.de>
 
+	PR middle-end/57287
+	* tree-ssa-copy.c (may_propagate_copy): Allow propagating
+	of default defs that appear in abnormal PHI nodes.
+
+2013-08-29  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/57685
 	* tree-vrp.c (register_edge_assert_for_1): Recurse only for
 	single-use operands to avoid exponential complexity.

gcc/testsuite/ChangeLog

 2013-08-29  Richard Biener  <rguenther@suse.de>
 
+	PR middle-end/57287
+	* gcc.dg/pr57287-2.c: New testcase.
+
+2013-08-29  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/57685
 	* gcc.dg/torture/pr57685.c: New testcase.
 

gcc/testsuite/gcc.dg/pr57287-2.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -Wall" } */
+
+#include <setjmp.h>
+
+struct node
+{
+  struct node *next;
+  char *name;
+} *list;
+
+struct node *list;
+struct node *head (void);
+
+sigjmp_buf *bar (void);
+
+int baz (void)
+{
+  struct node *n;
+  int varseen = 0;
+
+  list = head ();
+  for (n = list; n; n = n->next)
+    {
+      if (!varseen)
+	varseen = 1;
+
+      sigjmp_buf *buf = bar ();  /* { dg-bogus "may be used uninitialized" "" } */
+      __sigsetjmp (*buf, 1);
+    }
+
+  if (!varseen)
+    return 0;
+  return 1;
+}

gcc/tree-ssa-copy.c

@@ -60,7 +60,13 @@ may_propagate_copy (tree dest, tree orig)
 
   /* If ORIG flows in from an abnormal edge, it cannot be propagated.  */
   if (TREE_CODE (orig) == SSA_NAME
-      && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig))
+      && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig)
+      /* If it is the default definition and an automatic variable then
+         we can though and it is important that we do to avoid
+	 uninitialized regular copies.  */
+      && !(SSA_NAME_IS_DEFAULT_DEF (orig)
+	   && (SSA_NAME_VAR (orig) == NULL_TREE
+	       || TREE_CODE (SSA_NAME_VAR (orig)) == VAR_DECL)))
     return false;
 
   /* If DEST is an SSA_NAME that flows from an abnormal edge, then it