re PR tree-optimization/63841 (Incorrect strlen optimization after complete unroll)

2014-11-13  Teresa Johnson  <tejohnson@google.com>

gcc:
	PR tree-optimization/63841
	* tree-ssa-strlen.c (strlen_optimize_stmt): Ignore clobbers.

2014-11-13  Teresa Johnson  <tejohnson@google.com>

gcc/testsuite:
	PR tree-optimization/63841
	* g++.dg/tree-ssa/pr63841.C: Remove prints, use abort.

From-SVN: r217537

gcc/ChangeLog

+2014-11-13  Teresa Johnson  <tejohnson@google.com>
+
+	PR tree-optimization/63841
+	* tree-ssa-strlen.c (strlen_optimize_stmt): Ignore clobbers.
+
 2014-11-14  Bin Cheng  <bin.cheng@arm.com>
 
 	* timevar.def (TV_SCHED_FUSION): New time var.
@@ -106,6 +111,11 @@
 2014-11-13  Teresa Johnson  <tejohnson@google.com>
 
 	PR tree-optimization/63841
+	* tree-ssa-strlen.c (strlen_optimize_stmt): Ignore clobbers.
+
+2014-11-13  Teresa Johnson  <tejohnson@google.com>
+
+	PR tree-optimization/63841
 	* tree.c (initializer_zerop): A clobber does not zero initialize.
 
 2014-11-13  Ulrich Weigand  <Ulrich.Weigand@de.ibm.com>

gcc/testsuite/ChangeLog

+2014-11-13  Teresa Johnson  <tejohnson@google.com>
+
+	PR tree-optimization/63841
+	* g++.dg/tree-ssa/pr63841.C: Remove prints, use abort.
+
 2014-11-14  Bin Cheng  <bin.cheng@arm.com>
 
 	* gcc.target/arm/ldrd-strd-pair-1.c: New test.
@@ -11,6 +16,11 @@
 2014-11-13  Teresa Johnson  <tejohnson@google.com>
 
 	PR tree-optimization/63841
+	* g++.dg/tree-ssa/pr63841.C: Remove prints, use abort.
+
+2014-11-13  Teresa Johnson  <tejohnson@google.com>
+
+	PR tree-optimization/63841
 	* g++.dg/tree-ssa/pr63841.C: New test.
 
 2014-11-13  Richard Biener  <rguenther@suse.de>

gcc/testsuite/g++.dg/tree-ssa/pr63841.C

 /* { dg-do run } */
 /* { dg-options "-O2" } */
 
-#include <cstdio>
 #include <string>
 
 std::string __attribute__ ((noinline)) comp_test_write() {
@@ -29,10 +28,8 @@ std::string __attribute__ ((noinline)) comp_test_write_good() {
 
 int main() {
   std::string good = comp_test_write_good();
-  printf("expected: %hx\n", *(short*)good.c_str());
-
   std::string bad = comp_test_write();
-  printf("got: %hx\n", *(short*)bad.c_str());
 
-  return good != bad;
+  if (good != bad)
+    __builtin_abort ();
 }

gcc/tree-ssa-strlen.c

@@ -1934,7 +1934,7 @@ strlen_optimize_stmt (gimple_stmt_iterator *gsi)
 	    break;
 	  }
     }
-  else if (is_gimple_assign (stmt))
+  else if (is_gimple_assign (stmt) && !gimple_clobber_p (stmt))
     {
       tree lhs = gimple_assign_lhs (stmt);