[PATCH] Fix up ICE with reduction % (PR tree-optimization/55955)

[Jakub Jelinek]

Hi!

For *SHIFT_EXPR/*ROTATE_EXPR with VECTOR_TYPE types, optab_for_tree_code
requires us to decide if we want optab_vector or optab_scalar.  It is likely
not worth it to handle these four, they would fail soon anyway.

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

2013-01-14  Jakub Jelinek  <ja...@redhat.com>

        PR tree-optimization/55955
        * tree-vect-loop.c (vectorizable_reduction): Give up early on
        *SHIFT_EXPR and *ROTATE_EXPR codes.

        * gcc.c-torture/compile/pr55955.c: New test.

--- gcc/tree-vect-loop.c.jj     2013-01-11 09:02:55.000000000 +0100
+++ gcc/tree-vect-loop.c        2013-01-14 12:21:29.359018748 +0100
@@ -4776,6 +4776,17 @@ vectorizable_reduction (gimple stmt, gim
     {
       /* 4. Supportable by target?  */
 
+      if (code == LSHIFT_EXPR || code == RSHIFT_EXPR
+         || code == LROTATE_EXPR || code == RROTATE_EXPR)
+       {
+         /* Shifts and rotates are only supported by vectorizable_shifts,
+            not vectorizable_reduction.  */
+          if (dump_enabled_p ())
+           dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+                            "unsupported shift or rotation.");
+         return false;
+       }
+
       /* 4.1. check support for the operation in the loop  */
       optab = optab_for_tree_code (code, vectype_in, optab_default);
       if (!optab)
--- gcc/testsuite/gcc.c-torture/compile/pr55955.c.jj    2013-01-14 
12:23:28.273324350 +0100
+++ gcc/testsuite/gcc.c-torture/compile/pr55955.c       2013-01-14 
12:23:14.000000000 +0100
@@ -0,0 +1,12 @@
+/* PR tree-optimization/55955 */
+
+int b;
+
+void
+foo (int x)
+{
+  int a;
+  for (a = x; a < 2; a++)
+    for (b = 0; b < 2; b++)
+      *(unsigned short *) 0x100000UL %= 46;
+}

        Jakub