https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106902
--- Comment #23 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Alexander Monakov from comment #22) > Created attachment 55105 [details] > patch 1/3 > > (In reply to Richard Biener from comment #21) > > > > Sounds reasonable. Though I wouldn't use GENERIC folding but instead > > some folding-like code in c-family/ that for example would get invoked > > by genericization or via the gimplification hook? If we'd add GENERIC > > folding in fold-const.cc or match.pd the chance is that it will pick up > > FMAs "late". > > Agreed, thank you. I'm working on it. The attached patch implements this via > c_gimplify_expr and passes bootstrap+regtest under 'configure > --with-cpu=znver2' (i.e. with fma available by default). Hmm, seems like this should not be in the C family but the generic part of gimplifier. Because IIRC Fortran has similar rules but IIRC fortran front-end emits PAREN_EXPR a lot more which improves the situtation there ...
