Changeset 94500 in webkit for trunk/Source/JavaScriptCore/jit/SpecializedThunkJIT.h

Timestamp:

Sep 3, 2011, 10:43:47 PM (14 years ago)

Author:

[email protected]

Message:

ThunkGenerators does not convert positive double zero into integer zero
​https://bugs.webkit.org/show_bug.cgi?id=67553

Reviewed by Gavin Barraclough.

This is an 0.5% speed-up on V8 and neutral elsewhere.

• jit/SpecializedThunkJIT.h:

(JSC::SpecializedThunkJIT::returnDouble):

File:

• trunk/Source/JavaScriptCore/jit/SpecializedThunkJIT.h (modified) (1 diff)

trunk/Source/JavaScriptCore/jit/SpecializedThunkJIT.h

@@ -96 +96 @@
 #if USE(JSVALUE64)
             moveDoubleToPtr(src, regT0);
+            Jump zero = branchTestPtr(Zero, regT0);
             subPtr(tagTypeNumberRegister, regT0);
+            Jump done = jump();
+            zero.link(this);
+            move(tagTypeNumberRegister, regT0);
+            done.link(this);
 #else
             storeDouble(src, Address(stackPointerRegister, -(int)sizeof(double)));
             loadPtr(Address(stackPointerRegister, OBJECT_OFFSETOF(JSValue, u.asBits.tag) - sizeof(double)), regT1);
             loadPtr(Address(stackPointerRegister, OBJECT_OFFSETOF(JSValue, u.asBits.payload) - sizeof(double)), regT0);
+            Jump lowNonZero = branchTestPtr(NonZero, regT1);
+            Jump highNonZero = branchTestPtr(NonZero, regT0);
+            move(TrustedImm32(0), regT0);
+            move(TrustedImm32(Int32Tag), regT1);
+            lowNonZero.link(this);
+            highNonZero.link(this);
 #endif
             loadPtr(payloadFor(RegisterFile::CallerFrame, callFrameRegister), callFrameRegister);