On 10/01/2017 02:37 AM, Yuri Gribov wrote: > Hi all, > > (Previous mail was sent with spurious HTML, sorry!) > > This patch gets rid of float casts in comparisons when all values of > casted integral type are exactly representable by the float type > (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81376). > > Bootstrapped and regtested on x64_64. Ok to commit? > > -Y > > > pr81376-1.patch > > > From f6081c8fc1d9c20b686af3f4d8b09a5f60491cba Mon Sep 17 00:00:00 2001 > From: Yury Gribov <tetra2...@gmail.com> > Date: Fri, 29 Sep 2017 07:34:54 +0200 > Subject: [PATCH] 2017-09-29 Yury Gribov <tetra2...@gmail.com> > > PR middle-end/81376 > > gcc/ > * real.c (format_helper::can_represent_integral_type_p): New function > * real.h (format_helper::can_represent_integral_type_p): New function. > * match.pd: New pattern. > > gcc/testsuite/ > * c-c++-common/pr81376.c: New test. > --- > gcc/match.pd | 45 > ++++++++++++++++++++++++++++++------ > gcc/real.c | 13 +++++++++++ > gcc/real.h | 1 + > gcc/testsuite/c-c++-common/pr81376.c | 39 +++++++++++++++++++++++++++++++ > 4 files changed, 91 insertions(+), 7 deletions(-) > create mode 100644 gcc/testsuite/c-c++-common/pr81376.c > > diff --git a/gcc/match.pd b/gcc/match.pd > index 0863273..863c657 100644 > --- a/gcc/match.pd > +++ b/gcc/match.pd > @@ -2906,6 +2906,42 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) > (if (! HONOR_NANS (@0)) > (cmp @0 @1)))))) > > +/* Optimize various special cases of (FTYPE) N CMP (FTYPE) M. */ > +(for cmp (lt le eq ne ge gt) > + (simplify > + (cmp (float@0 @1) (float @2)) Since this runs on GENERIC as well as GIMPLE, I don't think you can rely on the types of the float expressions being the same?!? Which implies subsequent code will need and fmt1/fmt2 because you don't know they're necessarily the same.
Am I missing something? jeff
