re PR tree-optimization/61576 (wrong code at -O3 on x86_64-linux-gnu)

PR tree-optimization/61576

gcc/
	* tree-if-conv.c (is_cond_scalar_reduction): Add check that
	basic block containing reduction statement is predecessor
	of phi basi block.

gcc/testsuite/
	* gcc.dg/torture/pr61576.c: New test.

From-SVN: r212347

gcc/ChangeLog

+2014-07-08  Yuri Rumyantsev  <ysrumyan@gmail.com>
+
+	PR tree-optimization/61576
+	* tree-if-conv.c (is_cond_scalar_reduction): Add check that
+	basic block containing reduction statement is predecessor
+	of phi basi block.
+
 2014-07-08  Marek Polacek  <polacek@redhat.com>
 
 	PR c/60226

gcc/testsuite/ChangeLog

+2014-07-08  Yuri Rumyantsev  <ysrumyan@gmail.com>
+
+	PR tree-optimization/61576
+	* gcc.dg/torture/pr61576.c: New test.
+
 2014-07-08  Marek Polacek  <polacek@redhat.com>
 
 	PR c/60226

gcc/testsuite/gcc.dg/torture/pr61576.c

+/* { dg-do run } */
+
+#include <stdlib.h>
+volatile int a, b;
+int c, d, e, f;
+
+static int
+fn1 ()
+{
+  if (b)
+    {
+      d++;
+      e = c || f;
+    }
+  return 0;
+}
+
+int
+main ()
+{
+  for (; a < 1; a++)
+    {
+      fn1 ();
+      continue;
+    }
+  if (d != 0)
+    abort();
+  return 0;
+}

gcc/tree-if-conv.c

@@ -1407,7 +1407,8 @@ is_cond_scalar_reduction (gimple phi, gimple *reduc,
   gimple stmt;
   gimple header_phi = NULL;
   enum tree_code reduction_op;
-  struct loop *loop = gimple_bb (phi)->loop_father;
+  basic_block bb = gimple_bb (phi);
+  struct loop *loop = bb->loop_father;
   edge latch_e = loop_latch_edge (loop);
   imm_use_iterator imm_iter;
   use_operand_p use_p;
@@ -1447,6 +1448,11 @@ is_cond_scalar_reduction (gimple phi, gimple *reduc,
   if (!is_predicated (gimple_bb (stmt)))
     return false;
 
+  /* Check that stmt-block is predecessor of phi-block.  */
+  if (EDGE_PRED (bb, 0)->src != gimple_bb (stmt)
+      && EDGE_PRED (bb, 1)->src != gimple_bb (stmt))
+    return false;
+
   if (!has_single_use (lhs))
     return false;