[llvm] [MachineLateInstrsCleanup] Handle multiple kills for a preceding definition. (PR #119132)

[Matt Arsenault via llvm-commits]

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@@ -225,8 +231,8 @@ bool MachineLateInstrsCleanup::processBlock(MachineBasicBlock *MBB) {
         MBBDefs.erase(Reg);
         MBBKills.erase(Reg);
       } else if (MI.findRegisterUseOperandIdx(Reg, TRI, true /*isKill*/) != -1)
-        // Keep track of register kills.
-        MBBKills[Reg] = &MI;
+        // Keep track of all instructions that fully or partially kills Reg.
+        MBBKills[Reg].push_back(&MI);
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arsenm wrote:

You could also just do MRI.clearKillFlags any time it could matter 

https://github.com/llvm/llvm-project/pull/119132