[llvm] [AMDGPU] Rewrite GFX12 SGPR hazard handling to dedicated pass (PR #118750)

[Jay Foad via llvm-commits]

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@@ -1670,6 +1672,8 @@ void GCNPassConfig::addPreEmitPass() {
   // cases.
   addPass(&PostRAHazardRecognizerID);
 
+  addPass(&AMDGPUWaitSGPRHazardsLegacyID);
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jayfoad wrote:

> In theory InsertDelayAlu can adjust s_delay_alu settings based on presence of s_wait_alu instructions

Yes `AMDGPUInsertDelayAlu` does account for this, in that it knows that an extra `s_wait_alu` instruction will cause an extra single cycle issue delay which can avoid the need for an `s_delay_alu`. This does happen in some cases; see inline comment.

https://github.com/llvm/llvm-project/pull/118750