Hi! On Thu, Apr 23, 2020 at 02:34:03PM +0000, Zhanghaijian (A) wrote: > Thanks for your suggestions. I have modified accordingly. > Attached please find the adapted patch. Bootstrap and tested on aarch64 Linux > platform. > Does the v2 patch look batter? > > diff --git a/gcc/combine.c b/gcc/combine.c > index cff76cd3303..ad8a385fc48 100644 > --- a/gcc/combine.c > +++ b/gcc/combine.c > @@ -6643,7 +6643,8 @@ simplify_if_then_else (rtx x) > > /* Look for MIN or MAX. */ > > - if ((! FLOAT_MODE_P (mode) || flag_unsafe_math_optimizations) > + if ((! FLOAT_MODE_P (mode) > + || (!HONOR_NANS (mode) && !HONOR_SIGNED_ZEROS (mode))) > && comparison_p > && rtx_equal_p (XEXP (cond, 0), true_rtx) > && rtx_equal_p (XEXP (cond, 1), false_rtx)
> > The GENERIC folding routine producing > > min/max is avoiding it when those are honored (and it doesn't check > > flag_unsafe_math_optmizations at all). > > > > Certainly the patch is an incremental correct fix, with the flag > > testing replaced by the mode feature testing. > > Yeah, and the SMAX etc. definition is so weak that it isn't obvious that this > combine transform is valid without this flag. We can or should fix that, of > course :-) Please put flag_unsafe_math_optimizations back? It isn't clear at all that we do not need it. Also, do you have a changelog entry? Segher
