[llvm] [MemCpyOpt] No need to create `memcpy(a <- a)` (PR #98321)

[Yingwei Zheng via llvm-commits]

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@@ -139,6 +139,56 @@ define void @test6_memcpy(ptr %src, ptr %dest) nounwind {
   ret void
 }
 
+; FIXME: When forwarding to memcpy(arg+1, arg+1), we don't need to create this memcpy.
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dtcxzyw wrote:

Remove this FIXME.

https://github.com/llvm/llvm-project/pull/98321