[llvm] [X86][APX] Exclusively emit setzucc to avoid false dependency (PR #142092)

[Feng Zou via llvm-commits]

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@@ -122,7 +123,8 @@ bool X86FixupSetCCPass::runOnMachineFunction(MachineFunction &MF) {
       // register.
       Register ZeroReg = MRI->createVirtualRegister(RC);
       if (ST->hasZU()) {
-        MI.setDesc(TII->get(X86::SETZUCCr));
+        if (MI.getOpcode() != X86::SETZUCCr)
+          MI.setDesc(TII->get(X86::SETZUCCr));
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fzou1 wrote:

Updated to check ZU flag for SETZUCCr instruction in td and added assertion here to ensure MI is SETZUCCr instruction.

https://github.com/llvm/llvm-project/pull/142092