[llvm] [AMDGPU][SIInsertWaitcnts] Fix iota_range assertion when OtherMarks is empty in mergeAsyncMarks() (PR #193499)

[Shilei Tian via llvm-commits]

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@@ -3067,6 +3067,11 @@ bool WaitcntBrackets::mergeAsyncMarks(ArrayRef<MergeInfo> MergeInfos,
   unsigned OtherSize = OtherMarks.size();
   unsigned OurSize = AsyncMarks.size();
   unsigned MergeCount = std::min(OtherSize, OurSize);
+  // OtherMarks is empty → OtherSize == 0 → MergeCount == 0.
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shiltian wrote:

`→` is not ASICII. I'm not sure what our policy is, but I'd use `->` instead.

https://github.com/llvm/llvm-project/pull/193499