re PR tree-optimization/71439 (wrong code at -O3 in 32-bit and 64-bit mode on x86_64-linux-gnu)

2016-06-15  Alan Hayward  <alan.hayward@arm.com>

gcc/
	PR tree-optimization/71439
	* tree-vect-loop.c (vect_analyze_loop_operations): Additional check for
	live PHIs.

testsuite/
	PR tree-optimization/71439
	* gcc.dg/vect/pr71439.c: New

From-SVN: r237476

gcc/ChangeLog

+2016-06-15  Alan Hayward  <alan.hayward@arm.com>
+
+	PR tree-optimization/71439
+	* tree-vect-loop.c (vect_analyze_loop_operations): Additional check for
+	live PHIs.
+
 2016-06-15  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* ifcvt.c (bb_ok_for_noce_multiple_sets): Allow simple lowpart

gcc/testsuite/ChangeLog

+2016-06-15  Alan Hayward  <alan.hayward@arm.com>
+
+	PR tree-optimization/71439
+	* gcc.dg/vect/pr71439.c: New
+
 2016-06-15  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* gcc.target/aarch64/ifcvt_multiple_sets_subreg_1.c: New test.

gcc/testsuite/gcc.dg/vect/pr71439.c

+#include "tree-vect.h"
+
+int a, b, c;
+short fn1(int p1, int p2) { return p1 + p2; }
+
+int main() {
+  a = 0;
+  for (; a < 30; a = fn1(a, 4)) {
+    c = b;
+    b = 6;
+  }
+
+  if (c != 6)
+    abort ();
+
+  return 0;
+}

gcc/tree-vect-loop.c

@@ -1669,7 +1669,8 @@ vect_analyze_loop_operations (loop_vec_info loop_vinfo)
 
           gcc_assert (stmt_info);
 
-          if (STMT_VINFO_RELEVANT (stmt_info) == vect_used_in_scope
+          if ((STMT_VINFO_RELEVANT (stmt_info) == vect_used_in_scope
+               || STMT_VINFO_LIVE_P (stmt_info))
               && STMT_VINFO_DEF_TYPE (stmt_info) != vect_induction_def)
             {
               /* A scalar-dependence cycle that we don't support.  */
@@ -1686,6 +1687,9 @@ vect_analyze_loop_operations (loop_vec_info loop_vinfo)
                 ok = vectorizable_induction (phi, NULL, NULL);
             }
 
+	  if (ok && STMT_VINFO_LIVE_P (stmt_info))
+	    ok = vectorizable_live_operation (phi, NULL, NULL, -1, NULL);
+
           if (!ok)
             {
               if (dump_enabled_p ())