[llvm] [AMDGPU] Fixed verifier crash because of multiple live range components. (PR #190719)

[Dhruva Chakrabarti via llvm-commits]

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@@ -548,7 +548,23 @@ void AMDGPURewriteAGPRCopyMFMAImpl::eliminateSpillsOfReassignedVGPRs() const {
       // replacement vreg uses.
       LiveInterval &NewLI = LIS.createAndComputeVirtRegInterval(NewVReg);
       VRM.grow();
+
+      // A spill slot can be stored to multiple times, so the replacement
+      // vreg may have multiple disconnected live range components. Split
+      // them into separate vregs to maintain the single-component invariant.
+      SmallVector<LiveInterval *, 4> SplitLIs;
+      LIS.splitSeparateComponents(NewLI, SplitLIs);
+
+      LLVM_DEBUG(if (!SplitLIs.empty()) dbgs()
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dhruvachak wrote:

Done.

https://github.com/llvm/llvm-project/pull/190719