[PATCH] D118441: Preserve aliasing info during memory intrinsics lowering

[Nikita Popov via Phabricator via llvm-commits]

nikic added inline comments.


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Comment at: llvm/lib/Transforms/Utils/LowerMemIntrinsics.cpp:481
+    auto *DestSCEV = SE->getSCEV(Memcpy->getRawDest());
+    if (SE->isKnownPredicateAt(CmpInst::ICMP_NE, SrcSCEV, DestSCEV, Memcpy))
+      CanOverlap = false;
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arsenm wrote:
> Isn't this implied by the usual constraints of memcpy? The source and destination aren't allowed to overlap. Why does this need the SCEV check?
llvm.memcpy (unlike memcpy) is allowed to have src == dst (but no other overlap).


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  https://reviews.llvm.org/D118441/new/

https://reviews.llvm.org/D118441