re PR tree-optimization/86927 (Gcc miscompiles at -O3 on valid code)

2018-08-27  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/86927
	* tree-vect-loop.c (vect_create_epilog_for_reduction): Properly
	use const cond reduction code.

	* gcc.dg/vect/pr86927.c: New testcase.

From-SVN: r263888

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 123d76c..d27a7a8 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2018-08-27  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/86927
+       * tree-vect-loop.c (vect_create_epilog_for_reduction): Properly
+       use const cond reduction code.
+
 2018-08-27  Alexander Monakov  <amonakov@ispras.ru>
 
        PR tree-optimization/85758

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index aa957ee..8ebadb0 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-08-27  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/86927
+       * gcc.dg/vect/pr86927.c: New testcase.
+
 2018-08-27  David Malcolm  <dmalcolm@redhat.com>
 
        PR 87091

diff --git a/gcc/testsuite/gcc.dg/vect/pr86927.c b/gcc/testsuite/gcc.dg/vect/pr86927.c
new file mode 100644 (file)
index 0000000..794092b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr86927.c
@@ -0,0 +1,15 @@
+#include "tree-vect.h"
+
+int a[28];
+int main()
+{
+  check_vect ();
+  a[4] = 1;
+  int c = 1;
+  for (int b = 0; b < 8; b++)
+    if (a[b])
+      c = 0;
+  if (c)
+    abort();
+  return 0;
+}

diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index d5e3552..124a4be 100644 (file)
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -5197,6 +5197,9 @@ vect_create_epilog_for_reduction (vec<tree> vect_defs,
          if (STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info)
              == INTEGER_INDUC_COND_REDUCTION)
            code = induc_code;
+         else if (STMT_VINFO_VEC_REDUCTION_TYPE (stmt_info)
+                  == CONST_COND_REDUCTION)
+           code = STMT_VINFO_VEC_CONST_COND_REDUC_CODE (stmt_info);
          else
            code = MAX_EXPR;
        }