re PR tree-optimization/60382 (ICE on valid code at -O3 on x86_64-linux-gnu (in vect_...

2014-03-04  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/60382
	* tree-vect-loop.c (vect_is_simple_reduction_1): Do not consider
	dead PHIs a reduction.

	* gcc.dg/vect/pr60382.c: New testcase.

From-SVN: r208305

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6f5bd57bef0b72e7b9002b6f0bd4dbd0444d858a..ee70301094af991b951ab71115c2414b37b2e254 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2014-03-04  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/60382
+       * tree-vect-loop.c (vect_is_simple_reduction_1): Do not consider
+       dead PHIs a reduction.
+
 2014-03-03  Uros Bizjak  <ubizjak@gmail.com>
 
        * config/i386/xmmintrin.h (enum _mm_hint) <_MM_HINT_ET0>: Correct

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 3b0f81006e71062aed3dec01c5a1dbd11ddc7521..7ba86f7198551f0a752a457f2f8d063cc04ad784 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2014-03-04  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/60382
+       * gcc.dg/vect/pr60382.c: New testcase.
+
 2014-03-03  Jerry DeLisle  <jvdelisle@gcc.gnu>
 
        PR libfortran/60148

diff --git a/gcc/testsuite/gcc.dg/vect/pr60382.c b/gcc/testsuite/gcc.dg/vect/pr60382.c
new file mode 100644 (file)
index 0000000..a28c631
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr60382.c
@@ -0,0 +1,32 @@
+#include "tree-vect.h"
+
+int a, b, c, e, f;
+
+void
+foo ()
+{
+  for (b = 0; b < 3; b++)
+    if (e)
+      {
+       for (c = 0; c < 4; c++)
+         {
+           if (b)
+             continue;
+           f = 1;
+           for (a = 0; a < 2; a++)
+             f |= 1;
+         }
+       for (;;)
+         ;
+      }
+}
+
+int
+main ()
+{
+  check_vect ();
+  foo ();
+  return 0;
+}
+
+/* { dg-final { cleanup-tree-dump "vect" } } */

diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index 838803ebe520ef883ef28f422548020bd1339353..df6ab6fcb9ee2993b7f7023f591c5ed0b2b1f9fd 100644 (file)
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -2193,6 +2193,12 @@ vect_is_simple_reduction_1 (loop_vec_info loop_info, gimple phi,
               || (!check_reduction && flow_loop_nested_p (vect_loop, loop)));
 
   name = PHI_RESULT (phi);
+  /* ???  If there are no uses of the PHI result the inner loop reduction
+     won't be detected as possibly double-reduction by vectorizable_reduction
+     because that tries to walk the PHI arg from the preheader edge which
+     can be constant.  See PR60382.  */
+  if (has_zero_uses (name))
+    return NULL;
   nloop_uses = 0;
   FOR_EACH_IMM_USE_FAST (use_p, imm_iter, name)
     {