commit b01ff4034e82ba4e57ab417af9a79742dc522934
author sewardj <sewardj@8f6e269a-dfd6-0310-a8e1-e2731360e62c> Mon Aug 04 08:09:23 2014 +0000
committer sewardj <sewardj@8f6e269a-dfd6-0310-a8e1-e2731360e62c> Mon Aug 04 08:09:23 2014 +0000
tree 97c7846e5c708647a3a95f937d542f96191c892d
parent 257e99ff073746ef7402669ea9f522260fa3deeb

Add a folding rule: XorV128(t,0) ==> t.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2912 8f6e269a-dfd6-0310-a8e1-e2731360e62c

priv/ir_opt.c

diff --git a/priv/ir_opt.c b/priv/ir_opt.c
index bc019da..e2ad42d 100644
--- a/priv/ir_opt.c
+++ b/priv/ir_opt.c
@@ -2259,6 +2259,18 @@
                   e2 = mkZeroOfPrimopResultType(e->Iex.Binop.op);
                   break;
                }
+               /* XorV128(t,0) ==> t */
+               if (e->Iex.Binop.op == Iop_XorV128) {
+                  if (isZeroV128(e->Iex.Binop.arg2)) {
+                     e2 = e->Iex.Binop.arg1;
+                     break;
+                  }
+                  //Disabled because there's no known test case right now.
+                  //if (isZeroV128(e->Iex.Binop.arg1)) {
+                  //   e2 = e->Iex.Binop.arg2;
+                  //   break;
+                  //}
+               }
                break;
 
             case Iop_CmpNE32: