[llvm] [AArch64] Only clear kill flags if necessary when merging str (PR #69680)

[Matthias Braun via llvm-commits]

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@@ -997,8 +997,17 @@ AArch64LoadStoreOpt::mergePairedInsns(MachineBasicBlock::iterator I,
       //   STRWui %w0, ...
       //   USE %w1
       //   STRWui kill %w1  ; need to clear kill flag when moving STRWui upwards
-      RegOp0.setIsKill(false);
-      RegOp1.setIsKill(false);
+      for (auto It = std::next(I);
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MatzeB wrote:

The comment above this code block needs some updates after this change, no?

https://github.com/llvm/llvm-project/pull/69680