[all-commits] [llvm/llvm-project] 94f7c9: [cmake] Disable GCC lifetime DSE

[Sam James via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 94f7c961c78d8fdbc05898cfbbf88094de45c1ad
      https://github.com/llvm/llvm-project/commit/94f7c961c78d8fdbc05898cfbbf88094de45c1ad
  Author: Sam James <sam at gentoo.org>
  Date:   2023-05-13 (Sat, 13 May 2023)

  Changed paths:
    M llvm/cmake/modules/HandleLLVMOptions.cmake

  Log Message:
  -----------
  [cmake] Disable GCC lifetime DSE

LLVM data structures like llvm::User and llvm::MDNode rely on
the value of object storage persisting beyond the lifetime of the
object (#24952).  This is not standard compliant and causes a runtime
crash if LLVM is built with GCC and LTO enabled (#57740).  Until
these issues are fixed, we need to disable dead store eliminations
eliminations based on object lifetime.

Bug: https://github.com/llvm/llvm-project/issues/24952
Bug: https://github.com/llvm/llvm-project/issues/57740
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106943

Reviewed By: MaskRay, thesamesam, nikic

Differential Revision: https://reviews.llvm.org/D150505