[llvm] [AMDGPU] GFX12: select @llvm.prefetch intrinsic (PR #74576)

[Matt Arsenault via llvm-commits]

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@@ -3101,6 +3101,24 @@ void AMDGPURegisterBankInfo::applyMappingImpl(
       applyDefaultMapping(OpdMapper);
       constrainOpWithReadfirstlane(B, MI, 8); // M0
       return;
+    case Intrinsic::prefetch: {
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arsenm wrote:

This should have a G_ instruction.

Why erase here and not in the legalizer?

https://github.com/llvm/llvm-project/pull/74576