[clang] [llvm] [AMDGPU] Change CF intrinsics lowering to reconverge on predecessors. (PR #92809)

[Matt Arsenault via llvm-commits]

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@@ -15740,6 +15740,32 @@ void SITargetLowering::finalizeLowering(MachineFunction &MF) const {
     }
   }
 
+  // ISel inserts copy to regs for the successor PHIs
+  // at the BB end. We need to move the SI_WAVE_RECONVERGE right before the
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arsenm wrote:

Can you avoid this by gluing the pseudo to the root node? Also, I think you can avoid a second walk over the function by doing this in EmitInstrWithCustomInserter 

https://github.com/llvm/llvm-project/pull/92809