4 ms·
https://godbolt.org/z/v67Tc3jEc https://godbolt.org/z/v67Tc3jEc gcc and icc will use fma under `-O3`, but Clang won't.
by celrod 5y ago
https://godbolt.org/z/v67Tc3jEc https://godbolt.org/z/v67Tc3jEc
gcc and icc will use fma under `-O3`, but Clang won't.
- thxg 5y agogcc will avoid FMA if you specify `-std=c17` (or another C standard, instead of the default "GNU" variant). Note that it has to avoid FMA in that case because fusing (a * b) + c would not comply with the C17/IEEE-754 spec (see -fexcess-precision in the manual).