[PATCH] D123630: Remove connection between 'ffast-math' and 'ffp-contract'.

[Zahira Ammarguellat via Phabricator via cfe-commits]

zahiraam created this revision.
zahiraam added reviewers: aaron.ballman, andrew.w.kaylor, rjmccall, joerg, efriedma.
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Currently the options ‘ffast-math’ and the option ‘ffp-contract’ are connect. When ‘ffast-math’ is set, ffp-contract is altered this way:

-ffast-math/ Ofast -> ffp-contract=fast
-fno-fast-math     -> if ffp-contract= fast then ffp-contract=on else ffp-contract unchanged

This differs from gcc which doesn’t connect the two options, and triggered some spurious warnings; see issue https://github.com/llvm/llvm-project/issues/54625.

The source of the problem is that the ‘ffast-math’ option is an on/off flag, but the ‘ffp-contract’ is an on/off/fast flag. So when ‘fno-fast-math’ is used there is no 
obvious value for ‘ffp-contract’.

This patch is proposing a change to make the two options unrelated.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D123630

Files:
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/test/CodeGen/ffp-contract-option.c
  clang/test/CodeGen/ffp-model.c
  clang/test/Driver/clang_f_opts.c
  clang/test/Driver/fast-math.c

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