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AArch64:: Use 3 mov instructions to implement register swaps #9655

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AArch64:: Use 3 mov instructions to implement register swaps #9655

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8 changes: 5 additions & 3 deletions hphp/runtime/vm/jit/vasm-arm.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -758,9 +758,11 @@ void Vgen::emit(const copy2& i) {
assertx(d0 != d1);
if (d0 == s1) {
if (d1 == s0) {
a->Eor(X(d0), X(d0), X(s0));
a->Eor(X(s0), X(d0), X(s0));
a->Eor(X(d0), X(d0), X(s0));
a->SetScratchRegisters(vixl::NoReg, vixl::NoReg);
a->Mov(rVixlScratch0, X(d0));
a->Mov(X(d0), X(s0));
a->Mov(X(s0), rVixlScratch0);
a->SetScratchRegisters(rVixlScratch0, rVixlScratch1);
} else {
// could do this in a simplify pass
if (s1 != d1) a->Mov(X(s1), X(d1)); // save s1 first; d1 != s0
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