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

Author: jayfoad

llvm/lib/Target/AMDGPU/SIPreEmitPeephole.cpp

@@ -296,7 +296,7 @@ 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())
       continue;
     switch (I->getOpcode()) {
     case AMDGPU::S_SET_GPR_IDX_MODE:

llvm/test/CodeGen/AMDGPU/set-gpr-idx-peephole.mir

@@ -1,5 +1,6 @@
 # NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
 # RUN: llc -mtriple=amdgcn -mcpu=gfx900 -run-pass si-pre-emit-peephole -verify-machineinstrs -o - %s | FileCheck -check-prefix=GCN %s -implicit-check-not=S_SET_GPR_IDX
+# RUN: llc -mtriple=amdgcn -mcpu=gfx900 -run-pass si-pre-emit-peephole -verify-machineinstrs -o - %s -debugify-and-strip-all-safe | FileCheck -check-prefix=GCN %s -implicit-check-not=S_SET_GPR_IDX
 # RUN: llc -mtriple=amdgcn -mcpu=gfx900 -passes si-pre-emit-peephole -o - %s | FileCheck -check-prefix=GCN %s -implicit-check-not=S_SET_GPR_IDX
 
 ---
@@ -40,6 +41,27 @@ body:             |
   S_SET_GPR_IDX_OFF implicit-def $mode, implicit $mode
 ...
 
+---
+name:            meta_in_between
+body:             |
+  bb.0:
+    ; GCN-LABEL: name: meta_in_between
+    ; GCN: S_SET_GPR_IDX_ON $sgpr2, 1, implicit-def $m0, implicit-def $mode, implicit undef $m0, implicit $mode
+    ; GCN-NEXT: $vgpr16 = V_MOV_B32_indirect_read undef $vgpr1, implicit $exec, implicit $m0, implicit $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5_vgpr6_vgpr7_vgpr8_vgpr9_vgpr10_vgpr11_vgpr12_vgpr13_vgpr14_vgpr15
+    ; GCN-NEXT: KILL $sgpr0
+    ; GCN-NEXT: $sgpr0 = IMPLICIT_DEF
+    ; GCN-NEXT: $vgpr15 = V_MOV_B32_indirect_read undef $vgpr0, implicit $exec, implicit $m0, implicit killed $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5_vgpr6_vgpr7_vgpr8_vgpr9_vgpr10_vgpr11_vgpr12_vgpr13_vgpr14_vgpr15
+    ; GCN-NEXT: S_SET_GPR_IDX_OFF implicit-def $mode, implicit $mode
+  S_SET_GPR_IDX_ON $sgpr2, 1, implicit-def $m0, implicit-def $mode, implicit undef $m0, implicit $mode
+  $vgpr16 = V_MOV_B32_indirect_read undef $vgpr1, implicit $exec, implicit $m0, implicit $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5_vgpr6_vgpr7_vgpr8_vgpr9_vgpr10_vgpr11_vgpr12_vgpr13_vgpr14_vgpr15
+  S_SET_GPR_IDX_OFF implicit-def $mode, implicit $mode
+  KILL $sgpr0
+  $sgpr0 = IMPLICIT_DEF
+  S_SET_GPR_IDX_ON killed $sgpr2, 1, implicit-def $m0, implicit-def $mode, implicit undef $m0, implicit $mode
+  $vgpr15 = V_MOV_B32_indirect_read undef $vgpr0, implicit $exec, implicit $m0, implicit killed $vgpr0_vgpr1_vgpr2_vgpr3_vgpr4_vgpr5_vgpr6_vgpr7_vgpr8_vgpr9_vgpr10_vgpr11_vgpr12_vgpr13_vgpr14_vgpr15
+  S_SET_GPR_IDX_OFF implicit-def $mode, implicit $mode
+...
+
 ---
 name:            valu_write_in_between
 body:             |