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

[Matt Arsenault via llvm-commits]

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@@ -2801,19 +2804,21 @@ bool SIRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator MI,
                                                  /*AllowSpill=*/false);
           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);
-
-        MaterializedReg = DstReg;
-
-        OtherOp.ChangeToRegister(MaterializedReg, false);
-        OtherOp.setIsKill(true);
-        OtherOp.setIsRenamable(true);
+        // Avoid clobbering framereg if scavenger could not find a free sgpr.
+        if (DstReg) {
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arsenm wrote:

DstReg shouldn't be unset. If anything is conditional it should be on TmpReg 

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