Improve handling of unary plus.

src/hydrogen-instructions.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1418 matching lines @@
 }
 
 
 HValue* HSub::Canonicalize() {
   if (!representation().IsInteger32()) return this;
   if (CheckUsesForFlag(kTruncatingToInt32)) ClearFlag(kCanOverflow);
   return this;
 }
 
 
+// TODO(svenpanne) Use this in other Canonicalize() functions.
+static bool IsIdentityOperation(HValue* arg1, HValue* arg2, int32_t identity) {
+  return arg1->representation().IsSpecialization() &&
+      arg2->IsInteger32Constant() &&
+      arg2->GetInteger32Constant() == identity;
+}
+

[Jakob Kummerow, 2013/04/17 12:36:07]

nit: two newlines between top-level blocks

+HValue* HMul::Canonicalize() {
+  if (IsIdentityOperation(left(), right(), 1)) return left();
+  if (IsIdentityOperation(right(), left(), 1)) return right();
+  return this;
+}
+
+
 HValue* HChange::Canonicalize() {
   return (from().Equals(to())) ? value() : this;
 }
 
 
 HValue* HWrapReceiver::Canonicalize() {
   if (HasNoUses()) return NULL;
   if (receiver()->type().IsJSObject()) {
     return receiver();
   }
@@ skipping 2121 matching lines @@
 
 
 void HCheckFunction::Verify() {
   HInstruction::Verify();
   ASSERT(HasNoUses());
 }
 
 #endif
 
 } }  // namespace v8::internal