[PATCH] D50233: [InstCombine] Transform str(n)cmp to memcmp

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

> Does LLVM's implementation somehow guarantee that no later optimization pass comes along, sees the program reading uninitialized memory and declares UB?

In LLVM IR, reading uninitialized memory isn't itself UB; it's only UB if you perform certain operations on the result.  Granted, a naive LLVM IR implementation of memcmp might involve operations which lead to UB.


Repository:
  rL LLVM

https://reviews.llvm.org/D50233