re PR tree-optimization/82603 (ICE in ifcvt_local_dce w/ -O2 -ftree-loop-vectorize)

2017-10-20  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/82603
	* tree-if-conv.c (predicate_mem_writes): Make sure to only
	remove false predicated stores.

	* gcc.dg/torture/pr82603.c: New testcase.

From-SVN: r253933

gcc/ChangeLog

 2017-10-20  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/82603
+	* tree-if-conv.c (predicate_mem_writes): Make sure to only
+	remove false predicated stores.
+
+2017-10-20  Richard Biener  <rguenther@suse.de>
+
 	* graphite-isl-ast-to-gimple.c
 	(translate_isl_ast_to_gimple::graphite_copy_stmts_from_block):
 	Remove return value and simplify, dump copied stmt after lhs

gcc/testsuite/ChangeLog

+2017-10-20  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/82603
+	* gcc.dg/torture/pr82603.c: New testcase.
+
 2017-10-20  Tom de Vries  <tom@codesourcery.com>
 
 	* gcc.dg/tree-ssa/ldist-27.c: Remove dg-require-stack-size.

gcc/testsuite/gcc.dg/torture/pr82603.c

+/* { dg-do compile } */
+/* { dg-additional-options "-ftree-loop-vectorize" } */
+
+int
+mr (unsigned int lf, int ms)
+{
+  unsigned int sw = 0;
+  char *cu = (char *)&ms;
+
+  while (ms < 1)
+    {
+      if (lf == 0)
+	ms = 0;
+      else
+	ms = 0;
+      ms += ((lf > 0) && ((lf > sw) ? 1 : ++*cu));
+    }
+
+  if (lf != 0)
+    cu = (char *)&sw;
+  *cu = lf;
+
+  return ms;
+}

gcc/tree-if-conv.c

@@ -2214,7 +2214,8 @@ predicate_mem_writes (loop_p loop)
 	{
 	  if (!gimple_assign_single_p (stmt = gsi_stmt (gsi)))
 	    ;
-	  else if (is_false_predicate (cond))
+	  else if (is_false_predicate (cond)
+		   && gimple_vdef (stmt))
 	    {
 	      unlink_stmt_vdef (stmt);
 	      gsi_remove (&gsi, true);