[llvm] [AMDGPU] Skip debug instructions when eliminating S_SET_GPR_IDX_ON/OFF (PR #160715)

[Matt Arsenault via llvm-commits]

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@@ -299,7 +299,7 @@ bool SIPreEmitPeephole::optimizeSetGPR(MachineInstr &First,
   for (MachineBasicBlock::instr_iterator I = std::next(First.getIterator()),
                                          E = MI.getIterator();
        I != E; ++I) {
-    if (I->isBundle())
+    if (I->isBundle() || I->isDebugInstr())
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arsenm wrote:

IMPLICIT_DEF often survives RA, it is needed to maintain liveness across blocks 

https://github.com/llvm/llvm-project/pull/160715