Changeset 153242 in webkit for trunk/Source/JavaScriptCore/dfg/DFGCSEPhase.cpp

Timestamp:

Jul 24, 2013, 9:03:35 PM (12 years ago)

Author:

[email protected]

Message:

fourthTier: DFG should CSE MakeRope
​https://bugs.webkit.org/show_bug.cgi?id=117905

Source/JavaScriptCore:

Reviewed by Geoffrey Garen.

Adds MakeRope to the CSE phase and removes the comment that says that
we could do it but aren't doing it.

Also fixed SpeculatedType dumping so that if you have a Cell type then
it just prints "Cell" and if you just have Object then it just prints
"Object", instead of printing the long list of types.

• bytecode/SpeculatedType.cpp:

(JSC::dumpSpeculation):

• dfg/DFGCSEPhase.cpp:

(JSC::DFG::CSEPhase::performNodeCSE):

LayoutTests:

Reviewed by Geoffrey Garen.

This benchmark speeds up by 50%.

• fast/js/regress/make-rope-cse-expected.txt: Added.
• fast/js/regress/make-rope-cse.html: Added.
• fast/js/regress/script-tests/make-rope-cse.js: Added.

(foo):

File:

• trunk/Source/JavaScriptCore/dfg/DFGCSEPhase.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/dfg/DFGCSEPhase.cpp

@@ -1049 +1049 @@
         dataLogF("   %s @%u: ", Graph::opName(node->op()), node->index());
 #endif
-        
-        // NOTE: there are some nodes that we deliberately don't CSE even though we
-        // probably could, like MakeRope and ToPrimitive. That's because there is no
-        // evidence that doing CSE on these nodes would result in a performance
-        // progression. Hence considering these nodes in CSE would just mean that this
-        // code does more work with no win. Of course, we may want to reconsider this,
-        // since MakeRope is trivially CSE-able. It's not trivially doable for
-        // ToPrimitive, but we could change that with some speculations if we really
-        // needed to.
         
         switch (node->op()) {
@@ -1102 +1093 @@
         case CompareEqConstant:
         case ValueToInt32:
+        case MakeRope:
             if (cseMode == StoreElimination)
                 break;