[AMDGPU] Fix handling of DBG_VALUE_LIST while fixing the dead frame indices. (#109685)

Both SGPR->VGPR and VGPR->AGPR spilling code give a fixup to the spill
frame indices referred in debug instructions so that they can be
entirely removed. The stack argument is present at 0th index in
DBG_VALUE and at 2nd index for DBG_VALUE_LIST.

Fixes: SWDEV-484156

1 files changed, 9 insertions, 4 deletions

diff --git a/llvm/lib/Target/AMDGPU/SIFrameLowering.cpp b/llvm/lib/Target/AMDGPU/SIFrameLowering.cpp
index 2c67c4aedfe4..50a6f028f66d 100644
--- a/llvm/lib/Target/AMDGPU/SIFrameLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIFrameLowering.cpp
@@ -1418,10 +1418,15 @@ void SIFrameLowering::processFunctionBeforeFrameFinalized(
         // the debug value instructions. We should instead, update it with the
         // correct register value. But not sure the register value alone is
         for (MachineInstr &MI : MBB) {
-          if (MI.isDebugValue() && MI.getOperand(0).isFI() &&
-              !MFI.isFixedObjectIndex(MI.getOperand(0).getIndex()) &&
-              SpillFIs[MI.getOperand(0).getIndex()]) {
-            MI.getOperand(0).ChangeToRegister(Register(), false /*isDef*/);
+          if (MI.isDebugValue()) {
+            uint32_t StackOperandIdx = MI.isDebugValueList() ? 2 : 0;
+            if (MI.getOperand(StackOperandIdx).isFI() &&
+                !MFI.isFixedObjectIndex(
+                    MI.getOperand(StackOperandIdx).getIndex()) &&
+                SpillFIs[MI.getOperand(StackOperandIdx).getIndex()]) {
+              MI.getOperand(StackOperandIdx)
+                  .ChangeToRegister(Register(), false /*isDef*/);
+            }
           }
         }
       }