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OpcodeDispatcher: optimize test with small immediate

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Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
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Alyssa Rosenzweig committed 2024-08-21 17:52:22 -04:00
1 parent d53e689e22
commit db45f6eec8
1 file changed
+11 -2
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FEXCore/Source/Interface/Core/OpcodeDispatcher.cpp
+11 -2
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@@ -998,17 +998,26 @@ void OpDispatchBuilder::TESTOp(OpcodeArgs) {
auto Size = GetDstSize(Op);
// Optimize out masking constants
uint64_t Const;
bool AlwaysNonnegative = false;
if (IsValueConstant(WrapNode(Src), &Const)) {
// Optimize out masking constants
if (Const == (Size == 8 ? ~0ULL : ((1ull << Size * 8) - 1))) {
Src = Dest;
}
// Optimize test with non-sign bits
AlwaysNonnegative = (Const & (1ull << ((Size * 8) - 1))) == 0;
}
// Try to optimize out the AND.
if (Dest == Src) {
// Optimize out the AND.
SetNZP_ZeroCV(Size, Src);
} else if (Size < 4 && AlwaysNonnegative) {
// If we know the result is always nonnegative, we can use a 32-bit test.
auto Res = _And(OpSize::i32Bit, Dest, Src);
CalculatePF(Res);
SetNZ_ZeroCV(OpSize::i32Bit, Res);
} else {
HandleNZ00Write();
CalculatePF(_AndWithFlags(IR::SizeToOpSize(Size), Dest, Src));