[llvm] [AMDGPU] SIInstrInfo: Fix resultDependsOnExec for VOPC instructions (PR #134629)

[Jay Foad via llvm-commits]

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@@ -151,6 +151,9 @@ static bool resultDependsOnExec(const MachineInstr &MI) {
   // Ignore comparisons which are only used masked with exec.
   // This allows some hoisting/sinking of VALU comparisons.
   if (MI.isCompare()) {
+    if (SIInstrInfo::isVOPC(MI))
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jayfoad wrote:

> But the implicit write to VCC doesn't "depend on exec", right?

Well it does, because bits in VCC corresponding to disabled lanes in EXEC will be set to 0. Exactly the same as the explicit scalar def of a VOPC-promoted-to-VOP3 instruction.

https://github.com/llvm/llvm-project/pull/134629