[llvm] [AMDGPU] Support arbitrary types in amdgcn.dead (PR #134841)

[Matt Arsenault via llvm-commits]

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@@ -7651,6 +7651,12 @@ bool AMDGPULegalizerInfo::legalizeIntrinsic(LegalizerHelper &Helper,
     return legalizeLaneOp(Helper, MI, IntrID);
   case Intrinsic::amdgcn_s_buffer_prefetch_data:
     return legalizeSBufferPrefetch(Helper, MI);
+  case Intrinsic::amdgcn_dead: {
+    for (const MachineOperand &Def : MI.defs())
+      B.buildUndef(Def);
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arsenm wrote:

Should this be poison? Comment that it should be poison, we don't have a G_POISON yet

https://github.com/llvm/llvm-project/pull/134841