3 ms·

You can set fast math (or a subset of it) on a translation unit basis.

• tialaramex 2y ago
  Because the language works by textual inclusion and so a "translation unit" isn't really just your code this is much more likely to result in nasty surprises, up to and including ODR violations.
  • gpderetta 2y ago
    Yes, if you try hard enough I'm sure you can find ways to screw up. From a practical point of view it is fine.
• cozzyd 2y ago
  Or even on a per function basis, at least with gcc (no clue about clang...)
  • gpderetta 2y ago
    In principle yes, you can use Attribute optimize, but I wouldn't rely on it. Too many bugs open against it.
    • cozzyd 2y ago
      It's worked for me in the past but maybe I got lucky.
• pdw 2y ago
  That's not really true. If you link a shared library that was compiled with -ffast-math, that will affect the entire program. https://moyix.blogspot.com/2022/09/someones-been-messing-with-my-subnormals.html https://moyix.blogspot.com/2022/09/someones-been-messing-wit...
  • gpderetta 2y ago
    To enable this "feature" I believe you have to specify fast math while linking the .so, it is not enough to do it when compiling. It had also been fixed recent GCC versions.