Optimize compareStrictEq when neither side is a double and at least one is not a BigInt
https://bugs.webkit.org/show_bug.cgi?id=226755
<rdar://problem/79321542>
Reviewed by Yusuke Suzuki.
JSTests:
Made the error messages in stress/reflect-set a bit more informative in the process of debugging an issue with the patch.
(shouldBe):
(shouldThrow):
Source/JavaScriptCore:
This is a very similar patch to https://bugs.webkit.org/show_bug.cgi?id=226676.
The difference is that here we allow Strings on both side of the comparison, so we must add code to handle equality among strings.
Like for that other patch, the optimization is disabled for BigInt32.
Enabling it in that case would either need modifying the speculation (from banning HeapBigInt to banning all BigInts), or ensuring that we can never have a HeapBigInt so small it compares equal to a BigInt32.
I only implemented this optimization on 64-bits: it is just painful to write code that handles registers at such a low-level without a 32-bit machine to test things locally.
If anyone wants to make this optimization work on 32-bit, I don't foretell any major difficulty.
Finally, like quite a few other useKinds already, this case does not make the CompareStrictEq merge with an adjacent Branch.
The reason is simply that this patch relies on compileStringEquality, which currently does not support that feature.
I intend to fix this (for all useKinds at once) in a separate patch.
Effect on microbenchmarks:
poly-stricteq-not-double 46.8000+-0.4110 23.5872+-0.3061 definitely 1.9841x faster
poly-stricteq-not-double-nor-string 16.6880+-0.2317 16.3627+-0.3729 might be 1.0199x faster
poly-stricteq 49.2175+-0.6047 48.9532+-0.6758
I looked at how many cases of Untyped/Untyped compareStrictEq have been fixed by this patch and two other recent patches.
On JetStream2:
This leaves 20 instances of Untyped/Untyped.
On Speedometer2.0:
This leaves 75 instances of Untyped/Untyped.
- bytecode/SpeculatedType.h:
(JSC::isNeitherDoubleNorHeapBigIntSpeculation):
(JSC::DFG::doesGC):
(JSC::DFG::FixupPhase::fixupCompareStrictEqAndSameValue):
(JSC::DFG::Node::shouldSpeculateNeitherDoubleNorHeapBigInt):
(JSC::DFG::SafeToExecuteEdge::operator()):
- dfg/DFGSpeculativeJIT.cpp:
(JSC::DFG::SpeculativeJIT::compileStrictEq):
(JSC::DFG::SpeculativeJIT::emitBitwiseJSValueEquality):
(JSC::DFG::SpeculativeJIT::emitBranchOnBitwiseJSValueEquality):
(JSC::DFG::SpeculativeJIT::compileNotDoubleNeitherDoubleNorHeapBigIntNorStringStrictEquality):
(JSC::DFG::SpeculativeJIT::compilePeepHoleNotDoubleNeitherDoubleNorHeapBigIntNorStringStrictEquality):
(JSC::DFG::SpeculativeJIT::speculateNeitherDoubleNorHeapBigInt):
(JSC::DFG::SpeculativeJIT::speculateNeitherDoubleNorHeapBigIntNorString):
(JSC::DFG::SpeculativeJIT::speculate):
- dfg/DFGSpeculativeJIT.h:
- dfg/DFGSpeculativeJIT64.cpp:
(JSC::DFG::SpeculativeJIT::compileNeitherDoubleNorHeapBigIntToNotDoubleStrictEquality):
(WTF::printInternal):
(JSC::DFG::typeFilterFor):
(JSC::DFG::checkMayCrashIfInputIsEmpty):
(JSC::FTL::canCompile):
(JSC::FTL::DFG::LowerDFGToB3::compileCompareStrictEq):
