[PATCH] Fix genmatch SAVE_TEMPS usage for multi-uses

[Richard Biener]

This fixes the issue that genmatch wraps captures in SAVE_TEMPS
only for correctness reasons right now (for TREE_SIDE_EFFECTS
captures) but not to avoid duplicating expensive computations.

The following fixes that.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk,
testing on the branch right now.

Richard.

2015-11-26  Richard Biener  <rguent...@suse.de>

        * genmatch.c (dt_simplify::gen_1): For generic wrap all
        multi-result-use captures in a SAVE_EXPR.

Index: gcc/genmatch.c
===================================================================
--- gcc/genmatch.c      (revision 230924)
+++ gcc/genmatch.c      (working copy)
@@ -3112,16 +3111,10 @@ dt_simplify::gen_1 (FILE *f, int indent,
              {
                if (cinfo.info[i].same_as != (unsigned)i)
                  continue;
-               if (!cinfo.info[i].force_no_side_effects_p
-                   && cinfo.info[i].result_use_count > 1)
-                 {
-                   fprintf_indent (f, indent,
-                                   "if (TREE_SIDE_EFFECTS (captures[%d]))\n",
-                                   i);
-                   fprintf_indent (f, indent,
-                                   "  captures[%d] = save_expr 
(captures[%d]);\n",
-                                   i, i);
-                 }
+               if (cinfo.info[i].result_use_count > 1)
+                 fprintf_indent (f, indent,
+                                 "captures[%d] = save_expr (captures[%d]);\n",
+                                 i, i);
              }
          for (unsigned j = 0; j < e->ops.length (); ++j)
            {