Changeset 207060 in webkit for trunk/Source/JavaScriptCore/dfg/DFGLazyJSValue.cpp

Timestamp:

Oct 11, 2016, 12:28:08 AM (9 years ago)

Author:

[email protected]

Message:

ValueAdd should be constant folded if the operands are constant String,Primitive or Primitive,String
​https://bugs.webkit.org/show_bug.cgi?id=163182

Reviewed by Filip Pizlo.

JSTests:

• microbenchmarks/string-add-constant-folding.js: Added.

(assert):
(runTests):
(add):
(test):

Source/JavaScriptCore:

This code pattern shows up in Dromaeo, so it's worth optimizing for.
This might also show up in real world JS code due to inlining and other
types of constant folding.

• dfg/DFGByteCodeParser.cpp:

(JSC::DFG::ByteCodeParser::parseBlock):

• dfg/DFGLazyJSValue.cpp:

(JSC::DFG::LazyJSValue::getValue):

• dfg/DFGStrengthReductionPhase.cpp:

(JSC::DFG::StrengthReductionPhase::handleNode):

File:

• trunk/Source/JavaScriptCore/dfg/DFGLazyJSValue.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/dfg/DFGLazyJSValue.cpp

@@ -52 +52 @@
         return jsSingleCharacterString(&vm, u.character);
     case KnownStringImpl:
-    case NewStringImpl:
         return jsString(&vm, u.stringImpl);
+    case NewStringImpl:
+        return jsString(&vm, AtomicStringImpl::add(u.stringImpl));
     }
     RELEASE_ASSERT_NOT_REACHED();