[PATCH] D71726: Let clang atomic builtins fetch add/sub support floating point types

[James Y Knight via Phabricator via cfe-commits]

jyknight added a comment.

I still have the same fundamental objection as before to the parts of this patch for prohibiting FP add/sub on some targets.

If a particular LLVM target cannot handle transforming an FP add/sub (or any other RMW operations!) into the correct cmpxchg or LL/SC loop, that's a bug in the backend which should be fixed. I don't see why we ought to add a bunch of functionality in the frontend to workaround this?

(Some of the other changes, e.g. to diagnose lack of support for large atomics is useful, though.)


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  https://reviews.llvm.org/D71726/new/

https://reviews.llvm.org/D71726