[Openmp-commits] [PATCH] D97413: [OpenMP] Fix clang-cl build error regarding TSX intrinsics

Hans Wennborg via Phabricator via Openmp-commits openmp-commits at lists.llvm.org
Mon Mar 1 04:39:16 PST 2021

hans accepted this revision.
hans added a comment.
This revision is now accepted and ready to land.

In D97413#2588041 <https://reviews.llvm.org/D97413#2588041>, @jlpeyton wrote:

> In D97413#2587137 <https://reviews.llvm.org/D97413#2587137>, @hans wrote:
>> Oh, and I just realized: just because my machine supports RTM doesn't necessarily mean we want to use it, since these builds will then be used on all kinds of machines. This might be a bigger problem with the runtime's build config though.
> I think only the build compiler needs to support the instructions, not your machine.
> This shouldn't cause a problem since the RTM instrinsics are only used inside a specific lock kind which the user must select using an environment variable.

I see. Thanks for clarifying!

Comment at: openmp/runtime/cmake/config-ix.cmake:179
+    set(CMAKE_REQUIRED_FLAGS -mrtm)
+  endif()
I looked for how CMAKE_REQUIRED_FLAGS is used in other places, and this pattern seems common:


Maybe that is safer, in case CMAKE_REQUIRED_FLAGS already holds some flag that is important for the build.

  rG LLVM Github Monorepo



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