[llvm] [AArch64] Fold scalar-to-vector shuffles into DUP/FMOV (PR #166962)

[Amina Chabane via llvm-commits]

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@@ -696,6 +696,15 @@ static bool is64bitDefwithZeroHigh64bit(MachineInstr *MI,
   const TargetRegisterClass *RC = MRI->getRegClass(MI->getOperand(0).getReg());
   if (RC != &AArch64::FPR64RegClass)
     return false;
+  if (MI->getOpcode() == TargetOpcode::COPY) {
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Amichaxx wrote:

Yes, so I have since updated the peephole so that it no longer relies on the cross class COPY. When the “FPR64 COPY from GPR” case is detected, it's now turned it into a "real" FMOVXDr.

https://github.com/llvm/llvm-project/pull/166962