Try inverted comparison for match_simplify in phiopt

Since match and simplify does not have all of the inverted
comparison patterns, it make sense to just have
phi-opt try to do the inversion and try match and simplify again.

OK? Bootstrapped and tested on x86_64-linux-gnu.

Thanks,
Andrew Pinski

gcc/ChangeLog:

	* tree-ssa-phiopt.c (gimple_simplify_phiopt):
	If "A ? B : C" fails to simplify, try "(!A) ? C : B".

diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index 17bc597851be267d00a494d6c7c3507368a2c460..f8d7ae1c69ddb8b5e28ac2b57232d45ddf53f657 100644 (file)
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -836,7 +836,8 @@ phiopt_early_allow (enum tree_code code)
    with parts pushed if EARLY_P was true. Also rejects non allowed tree code
    if EARLY_P is set.
    Takes the comparison from COMP_STMT and two args, ARG0 and ARG1 and tries
-   to simplify CMP ? ARG0 : ARG1.  */
+   to simplify CMP ? ARG0 : ARG1.
+   Also try to simplify (!CMP) ? ARG1 : ARG0 if the non-inverse failed.  */
 static tree
 gimple_simplify_phiopt (bool early_p, tree type, gimple *comp_stmt,
                        tree arg0, tree arg1,
@@ -869,6 +870,30 @@ gimple_simplify_phiopt (bool early_p, tree type, gimple *comp_stmt,
            return result;
        }
     }
+  /* Try the inverted comparison, that is !COMP ? ARG1 : ARG0. */
+  comp_code = invert_tree_comparison (comp_code, HONOR_NANS (cmp0));
+
+  if (comp_code == ERROR_MARK)
+    return NULL;
+
+  cond = build2_loc (loc,
+                    comp_code, boolean_type_node,
+                    cmp0, cmp1);
+  gimple_match_op op1 (gimple_match_cond::UNCOND,
+                      COND_EXPR, type, cond, arg1, arg0);
+
+  if (op1.resimplify (early_p ? NULL : seq, follow_all_ssa_edges))
+    {
+      /* Early we want only to allow some generated tree codes. */
+      if (!early_p
+         || op1.code.is_tree_code ()
+         || phiopt_early_allow ((tree_code)op1.code))
+       {
+         result = maybe_push_res_to_seq (&op1, seq);
+         if (result)
+           return result;
+       }
+    }
 
   return NULL;
 }