On Wed, Jun 21, 2023 at 10:39 PM Joseph Myers <jos...@codesourcery.com> wrote: > > On Wed, 21 Jun 2023, Richard Biener via Gcc-patches wrote: > > > > > int32_t x = (int32_t)0x1.0p32; > > > > int32_t y = (int32_t)(int64_t)0x1.0p32; > > > > > > > > sets x to 2147483647 and y to 0. > > > > Hmm, good question. GENERIC has a direct truncation to unsigned char > > for example, the C standard generally says if the integral part cannot > > be represented then the behavior is undefined. So I think we should be > > safe here (0x1.0p32 doesn't fit an int). > > We should be following Annex F (unspecified value plus "invalid" exception > for out-of-range floating-to-integer conversions rather than undefined > behavior). But we don't achieve that very well at present (see bug 93806 > comments 27-29 for examples of how such conversions produce wobbly > values).
That would mean guarding this with !flag_trapping_math would be the appropriate thing to do. Richard. > -- > Joseph S. Myers > jos...@codesourcery.com
