[llvm] RegAllocGreedy: Check if copied lanes are live in trySplitAroundHintReg (PR #160424)

[Carl Ritson via llvm-commits]

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@@ -235,7 +235,7 @@ define half @f12_half(half %dummy, half %val, ptr %dest) {
 ; CHECK-NEXT: blah %f0
 ; CHECK-NEXT: #NO_APP
 ; CHECK-NEXT: brasl %r14, __extendhfsf2 at PLT
-; CHECK-NEXT: ltebr %f0, %f0
+; CHECK-NEXT: ltebr %f1, %f0
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perlfu wrote:

Just noise perhaps, but it seems odd to use `%f1` when `%f0` is "available".
>From a distance it looks like it could be a side-effect of the code now considering the liveness of defs.

https://github.com/llvm/llvm-project/pull/160424