[PATCH] Fix parloops ICE (PR tree-optimization/81578)

[Jakub Jelinek]

Hi!

Not all vectorizable reductions are valid OpenMP standard reductions
(we could create user defined reductions from that, but that would be
quite a lot of work).

This patch bails out for unsupported reductions.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2017-07-27  Jakub Jelinek  <ja...@redhat.com>

        PR tree-optimization/81578
        * tree-parloops.c (build_new_reduction): Bail out if
        reduction_code isn't one of the standard OpenMP reductions.
        Move the details printing after that decision.

        * gcc.dg/pr81578.c: New test.

--- gcc/tree-parloops.c.jj      2017-07-19 14:01:24.000000000 +0200
+++ gcc/tree-parloops.c 2017-07-27 14:27:13.966749227 +0200
@@ -2475,23 +2475,39 @@ build_new_reduction (reduction_info_tabl
 
   gcc_assert (reduc_stmt);
 
-  if (dump_file && (dump_flags & TDF_DETAILS))
-    {
-      fprintf (dump_file,
-              "Detected reduction. reduction stmt is:\n");
-      print_gimple_stmt (dump_file, reduc_stmt, 0);
-      fprintf (dump_file, "\n");
-    }
-
   if (gimple_code (reduc_stmt) == GIMPLE_PHI)
     {
       tree op1 = PHI_ARG_DEF (reduc_stmt, 0);
       gimple *def1 = SSA_NAME_DEF_STMT (op1);
       reduction_code = gimple_assign_rhs_code (def1);
     }
-
   else
     reduction_code = gimple_assign_rhs_code (reduc_stmt);
+  /* Check for OpenMP supported reduction.  */
+  switch (reduction_code)
+    {
+    case PLUS_EXPR:
+    case MULT_EXPR:
+    case MAX_EXPR:
+    case MIN_EXPR:
+    case BIT_IOR_EXPR:
+    case BIT_XOR_EXPR:
+    case BIT_AND_EXPR:
+    case TRUTH_OR_EXPR:
+    case TRUTH_XOR_EXPR:
+    case TRUTH_AND_EXPR:
+      break;
+    default:
+      return;
+    }
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      fprintf (dump_file,
+              "Detected reduction. reduction stmt is:\n");
+      print_gimple_stmt (dump_file, reduc_stmt, 0);
+      fprintf (dump_file, "\n");
+    }
 
   new_reduction = XCNEW (struct reduction_info);
 
--- gcc/testsuite/gcc.dg/pr81578.c.jj   2017-07-27 14:48:16.426441581 +0200
+++ gcc/testsuite/gcc.dg/pr81578.c      2017-07-27 14:48:01.000000000 +0200
@@ -0,0 +1,12 @@
+/* PR tree-optimization/81578 */
+/* { dg-do compile { target pthread } } */
+/* { dg-options "-O2 -ftree-parallelize-loops=2" } */
+
+int
+foo (int *x)
+{
+  int i, r = 1;
+  for (i = 0; i != 1024; i++)
+    r *= x[i] < 0;
+  return r;
+}

        Jakub