[llvm] [Coalescer] Consider NewMI's subreg index when updating lanemask. (PR #121780)

[Sander de Smalen via llvm-commits]

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@@ -1508,14 +1508,14 @@ bool RegisterCoalescer::reMaterializeTrivialDef(const CoalescerPair &CP,
     //    undef %2.subreg:reg = INST %1:reg         ; DefMI (rematerializable),
     //                                              ; DefSubIdx = subreg
     //    %3:reg = COPY %2                          ; SrcIdx = DstIdx = 0
-    //    .... = SOMEINSTR %3:reg
+    //    .... = SOMEINSTR %3:reg, %2
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sdesmalen-arm wrote:

It wasn't, thanks. Your question did trigger me to clarify the existing comment a bit though! :)

https://github.com/llvm/llvm-project/pull/121780