Relax fma check in configure for Visual Studio
#12518
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I am going to approve this PR because the code seems definitely correct to I just have one question about a comment: I am unsure how to understand "broken implementations of Cygwin64, mingw-w64 (x86_64) Visual |
It needs the context of the line before! "These tests trigger the broken implementations of ..." - one or more of those three tests (from |
Visual Studio 2019 onwards is assumed by configure to have a working `fma`. This assumption was not quite correct - Visual Studio 2019 in fact fixed the use of hardware fma support. If that is unavailable, the same broken fallback function is used.
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This is macOS's last chance in CI - if the beat test fails again, we should disable it (as on trunk) |
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It does seem better to also disable |
In #944, Visual Studio 2019 onwards is assumed by
configureto have a workingfmafunction, and it's a hard error if it fails the checks for it. This assumption is not quite correct - Visual Studio 2019 in fact fixed the use of hardware fma support, not the software version of the function. If that hardware support is unavailable, the same broken fallback function is used.Fixes #12513 (NB this is for 4.14, as this only affects MSVC; see also #12519 for trunk)