Changeset 193989 in webkit for trunk/Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp

Timestamp:

Dec 11, 2015, 3:45:04 PM (10 years ago)

Author:

[email protected]

Message:

[JSC] Add an implementation of pow() taking an integer exponent to B3
​https://bugs.webkit.org/show_bug.cgi?id=152165

Reviewed by Mark Lam.

LLVM has this really neat optimized opcode for
raising the power of something by an integer exponent.

There is no such native instruction so we need to extend
the existing FTLOutput API to something efficient.

DFG has a pretty competitive implementation. In this patch,
I added a version of it to B3.
I created powDoubleInt32() instead of putting the code directly
in FTL for easier testing and optimization.

• CMakeLists.txt:
• JavaScriptCore.xcodeproj/project.pbxproj:
• b3/B3MathExtras.cpp: Added.

(JSC::B3::powDoubleInt32):

• b3/B3MathExtras.h: Added.
• b3/B3MemoryValue.h:
• b3/testb3.cpp:

(JSC::B3::testPowDoubleByIntegerLoop):
(JSC::B3::run):

• dfg/DFGSpeculativeJIT.cpp:

(JSC::DFG::compileArithPowIntegerFastPath):

• ftl/FTLB3Output.cpp:

(JSC::FTL::Output::doublePowi):

• ftl/FTLB3Output.h:

(JSC::FTL::Output::doublePowi): Deleted.

File:

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

trunk/Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp

@@ -4224 +4224 @@
 {
     MacroAssembler::JumpList skipFastPath;
-    skipFastPath.append(assembler.branch32(MacroAssembler::LessThan, yOperand, MacroAssembler::TrustedImm32(0)));
-    skipFastPath.append(assembler.branch32(MacroAssembler::GreaterThan, yOperand, MacroAssembler::TrustedImm32(1000)));
+    skipFastPath.append(assembler.branch32(MacroAssembler::Above, yOperand, MacroAssembler::TrustedImm32(1000)));
 
     static const double oneConstant = 1.0;