[all-commits] [llvm/llvm-project] 3db678: Check result of emitStrLen before passing it to Cr...

[Dimitry Andric via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 3db6783d8a7da05a5949bb18e6c8809306c9d0de
      https://github.com/llvm/llvm-project/commit/3db6783d8a7da05a5949bb18e6c8809306c9d0de
  Author: Dimitry Andric <dimitry at andric.com>
  Date:   2019-11-14 (Thu, 14 Nov 2019)

  Changed paths:
    M llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
    A llvm/test/Transforms/InstCombine/pr43081.ll

  Log Message:
  -----------
  Check result of emitStrLen before passing it to CreateGEP

Summary:
This fixes PR43081, where the transformation of `strchr(p, 0) -> p +
strlen(p)` can cause a segfault, if `-fno-builtin-strlen` is used.  In
that case, `emitStrLen` returns nullptr, which CreateGEP is not designed
to handle.  Also add the minimized code from the PR as a test case.

Reviewers: xbolva00, spatel, jdoerfert, efriedma

Reviewed By: efriedma

Subscribers: lebedev.ri, hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D70143