[llvm] [CodeGen] MachineVerifier to check early-clobber constraint (PR #151421)

[Abhay Kanhere via llvm-commits]

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@@ -584,6 +584,7 @@ bool AMDGPUInstructionSelector::selectG_AMDGPU_MAD_64_32(
   I.setDesc(TII.get(Opc));
   I.addOperand(*MF, MachineOperand::CreateImm(0));
   I.addImplicitDefUseOperands(*MF);
+  I.getOperand(0).setIsEarlyClobber(true);
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AbhayKanhere wrote:

Internally we discussed a variant for  MI.setDesc(MCID, bool updateOpConstraint=false) that updates OperandConstraints if passed true, but setDesc is often part of a set of update operations and not the last so it is not always possible to update constraints there.

https://github.com/llvm/llvm-project/pull/151421