[PATCH] D130666: [InstCombine] Add support for strlcpy folding

[Martin Sebor via Phabricator via llvm-commits]

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The middle end support for `strlcpy` consists of transforming calls to `__strlcpy_chk` to the function itself if the buffer overflow checking overhead can be avoided.  This change extends the support to also optimize a subset of calls to the function itself, similar to `snprintf`.

The `strlcpy` and `strlcat` functions have both recently been added to the next revision of POSIX (see issue 986 <https://www.austingroupbugs.net/view.php?id=986>).  If/when this proposed enhancement is accepted I'll look into adding minimal support for `strlcat` as well.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D130666

Files:
  llvm/include/llvm/Transforms/Utils/SimplifyLibCalls.h
  llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
  llvm/test/Transforms/InstCombine/fortify-folding.ll
  llvm/test/Transforms/InstCombine/strlcpy-1.ll

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