[llvm] [AMDGPU] Fix GFX1250 hazard: S_SET_VGPR_MSB dropped (PR #184904)

[Jay Foad via llvm-commits]

jayfoad wrote:

> It's a huge change and hazard recognizer mitigates the hazard for instruction which does not exist yet. Why not to insert nops in the VGPR lowering pass itself?

Why not swap the order of passes so that GCNHazardRcognizer runs after AMDGPULowerVGPREncoding? That's how I assumed it was already. That's why I suggested fixing it in the hazard recognizer.

https://github.com/llvm/llvm-project/pull/184904