On Mon, Aug 7, 2023 at 1:20 PM Richard Biener <richard.guent...@gmail.com> wrote:
> > Please also note the RFC patch [1] that relaxes clears for V2SFmode > > with -fno-trapping-math. The patched compiler will then emit the same > > code as clang does for -O2. Which raises another question - should gcc > > default to -fno-trapping-math? > > I think we discussed this before and yes, IMHO we should default to > -fno-trapping-math at least for C/C++ to be consistent with our other > handling of the FP environment (default to -fno-rounding-math) and > lack of proper FENV access barriers for inspecting the exceptions. > > Note Fortran has the -ffpe-trap= option which would then need to make > sure to also enable -ftrapping-math. Ada might have similar constraints > (it also uses -fnon-call-exceptions, but unless it enables CPU traps for > FP exceptions that would be a no-op). Note this also shows we should > possibly separate maintaining the IEEE exception state and considering > changes in the IEEE exception states to cause CPU traps (that's also > a source of common confusion on the user side). FTR: PR54192, "-fno-trapping-math by default?" [1] [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54192 Uros.
