[PATCH] Fix PR92558

[Richard Biener]

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

2019-11-18  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/92558
        * tree-vect-loop.c (vect_create_epilog_for_reduction): When
        reducting the width of a reduction vector def update new_phis.

        * gcc.dg/vect/pr92558.c: New testcase.

Index: gcc/tree-vect-loop.c
===================================================================
--- gcc/tree-vect-loop.c        (revision 278389)
+++ gcc/tree-vect-loop.c        (working copy)
@@ -5198,6 +5198,7 @@ vect_create_epilog_for_reduction (stmt_v
          new_temp = make_ssa_name (vectype1);
          epilog_stmt = gimple_build_assign (new_temp, code, dst1, dst2);
          gsi_insert_before (&exit_gsi, epilog_stmt, GSI_SAME_STMT);
+         new_phis[0] = epilog_stmt;
        }
 
       if (reduce_with_shift && !slp_reduc)
Index: gcc/testsuite/gcc.dg/vect/pr92558.c
===================================================================
--- gcc/testsuite/gcc.dg/vect/pr92558.c (nonexistent)
+++ gcc/testsuite/gcc.dg/vect/pr92558.c (working copy)
@@ -0,0 +1,23 @@
+/* { dg-additional-options "-mavx2" { target avx2_runtime } } */
+
+void __attribute__((noipa))
+foo (int * __restrict wsum, int * __restrict cff, int * __restrict weight)
+{
+  for (int i = 0; i < 16; ++i)
+    {
+      *wsum += weight[2*i+0];
+      *cff += weight[2*i+1];
+    }
+}
+
+int main()
+{
+  int weight[32];
+  for (int i = 0; i < 32; ++i)
+    weight[i] = i;
+  int wsum = 0, cff = 0;
+  foo (&wsum, &cff, weight);
+  if (wsum != 240 || cff != 256)
+    __builtin_abort ();
+  return 0;
+}