[PATCH] Fix SLP vectorization ICE (PR tree-optimization/71823)

[Jakub Jelinek]

Hi!

vect_get_vec_defs handles only one or two arguments, for ternary
ops like fma vectorizable_operation calls vect_get_vec_defs on the
first two arguments, and then did
             vec_oprnds2.create (1);
             vec_oprnds2.quick_push (vect_get_vec_def_for_operand (op2,   
                                                                   stmt));
which is what vect_get_vec_defs does, but only for loop vectorization.
The following patch uses vect_get_vec_defs again so that it does what it
did before for loop vectorization, but additionally handles properly
slp vectorization.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk/6.2?

2016-07-11  Jakub Jelinek  <ja...@redhat.com>

        PR tree-optimization/71823
        * tree-vect-stmts.c (vectorizable_operation): Use vect_get_vec_defs
        to get vec_oprnds2 from op2.

        * gcc.dg/vect/pr71823.c: New test.

--- gcc/tree-vect-stmts.c.jj    2016-07-07 20:40:43.000000000 +0200
+++ gcc/tree-vect-stmts.c       2016-07-11 12:05:52.501823209 +0200
@@ -5362,11 +5362,8 @@ vectorizable_operation (gimple *stmt, gi
            vect_get_vec_defs (op0, NULL_TREE, stmt, &vec_oprnds0, NULL,
                               slp_node, -1);
          if (op_type == ternary_op)
-           {
-             vec_oprnds2.create (1);
-             vec_oprnds2.quick_push (vect_get_vec_def_for_operand (op2,
-                                                                   stmt));
-           }
+           vect_get_vec_defs (op2, NULL_TREE, stmt, &vec_oprnds2, NULL,
+                              slp_node, -1);
        }
       else
        {
--- gcc/testsuite/gcc.dg/vect/pr71823.c.jj      2016-07-11 12:07:41.687485519 
+0200
+++ gcc/testsuite/gcc.dg/vect/pr71823.c 2016-07-11 12:08:42.449741939 +0200
@@ -0,0 +1,14 @@
+/* PR tree-optimization/71823 */
+/* { dg-do compile } */
+/* { dg-additional-options "-mfma" { target i?86-*-* x86_64-*-* } } */
+
+float a[4], b[4];
+
+int
+main ()
+{
+  int i;
+  for (i = 0; i < 4; ++i)
+    b[i] = __builtin_fma (1024.0f, 1024.0f, a[i]);
+  return 0;
+}

        Jakub