[llvm] [AMDGPU] frame index elimination hit assertion for scavenged nonreg (PR #130287)

[Pankaj Dwivedi via llvm-commits]

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@@ -2802,18 +2805,20 @@ bool SIRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator MI,
           DstReg = TmpReg;
         }
 
-        auto AddI32 = BuildMI(*MBB, *MI, DL, MI->getDesc())
-                          .addDef(DstReg, RegState::Renamable)
-                          .addReg(MaterializedReg, RegState::Kill)
-                          .add(OtherOp);
-        if (DeadSCC)
-          AddI32.setOperandDead(3);
+        if (TmpReg) {
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PankajDwivedi-25 wrote:

well, here we have reached at the point, where we update the original DstReg with TmpReg.
so now if tmp is valid it will work perfectly. In the case if it is not we have to make condition on `DstReg` or `TmpReg`.
`Materializedreg` is `FrameReg` at this point making check on that, I don't think make sense? 

obviously `TmpReg` is not getting used directly but we update here `DstReg` with `TmpReg`. 

https://github.com/llvm/llvm-project/pull/130287