On Thu, 23 Oct 2025, Zhou Zhao wrote:
>
> 在 2025/8/27 下午5:01, Richard Biener 写道:
> > On Wed, 27 Aug 2025, zhaozhou wrote:
> >
> >> From: Zhou Zhao <[email protected]>
> >>
> >> This patch is a respond of the patch posted at
> >> https://gcc.gnu.org/pipermail/gcc-patches/2025-August/693307.html
> >> as some suggestion by Richard Biener, I have adopted these suggestions
> >> and regenerated the patch.
> >>
> >> In addition, I noticed that ignore the issue of expanding FLOOR and
> >> CEIL in my pattern (for op(lt ge) bt(FLOOR CEIL)...), its will be fail
> >> to cover all the expected patterns, and it will unfortunately cover
> >> some unexpected patterns. Now I'm fixed this in the current submission.
> >>
> >> In the 538.imagick_r benchmark of Spec2017, I find these pattern from
> >> MagickRound function. This patch implements these pattern in match.pd
> >> for 4 rules:
> >> 1) (x-floor(x)) < (ceil(x)-x) ? floor(x) : ceil(x) -> floor(x+0.5)
> >> 2) (x-floor(x)) >= (ceil(x)-x) ? ceil(x) : floor(x) -> floor(x+0.5)
> >> 3) (ceil(x)-x) > (x-floor(x)) ? floor(x) : ceil(x) -> floor(x+0.5)
> >> 4) (ceil(x)-x) <= (x-floor(x)) ? ceil(x) : floor(x) -> floor(x+0.5)
> >>
> >> The patch implements floor(x+0.5) operation to replace these pattern
> >> that semantics of round(x) function.
> >>
> >> The patch was regtested on aarch64-linux-gnu and x86_64-linux-gnu,
> >> SPEC 2017 and SPEC 2006 were run:
> >> As for SPEC 2017, 538.imagick_r benchmark performance increased by 3%+
> >> in base test of ratio mode.
> >> As for SPEC 2006, while the transform does not seem to be triggered,
> >> we also see no non-noise impact on performance.
> >> OK for mainline?
> > OK.
> >
> > Thanks,
> > Richard.
>
> Hi, Richard
>
> Would it be possible to merge this patch when you have a moment?
> Thank you for your time and consideration.
Can you bounce the patch to me again in a form suitable for 'git am'
and 'git push', aka with a formatted commit message that passes
pre-commit checks?
Thanks,
Richard.
> zhou zhao.
>
> >> gcc/ChangeLog:
> >>
> >> * match.pd: Add new pattern for round.
> >>
> >> gcc/testsuite/ChangeLog:
> >>
> >> * gcc.dg/fold-round-1.c: New test.
> >> ---
> >> gcc/match.pd | 21 +++++++++++
> >> gcc/testsuite/gcc.dg/fold-round-1.c | 56 +++++++++++++++++++++++++++++
> >> 2 files changed, 77 insertions(+)
> >> create mode 100644 gcc/testsuite/gcc.dg/fold-round-1.c
> >>
> >> diff --git a/gcc/match.pd b/gcc/match.pd
> >> index b1d7a3a1b73..788946af0f1 100644
> >> --- a/gcc/match.pd
> >> +++ b/gcc/match.pd
> >> @@ -794,6 +794,27 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> >> (rdiv @0 (negate @1))
> >> (rdiv (negate @0) @1))
> >> +/* convert semantics of round(x) function to floor(x+0.5). */
> >> +/* (x-floor(x)) < (ceil(x)-x) ? floor(x) : ceil(x) --> floor(x+0.5). */
> >> +/* (x-floor(x)) >= (ceil(x)-x) ? ceil(x) : floor(x) --> floor(x+0.5). */
> >> +/* (ceil(x)-x) > (x-floor(x)) ? floor(x) : ceil(x) --> floor(x+0.5). */
> >> +/* (ceil(x)-x) <= (x-floor(x)) ? ceil(x) : floor(x) --> floor(x+0.5). */
> >> +(for op (lt lt lt lt ge ge ge ge)
> >> + bt (BUILT_IN_FLOORF BUILT_IN_FLOOR BUILT_IN_FLOORL IFN_FLOOR
> >> + BUILT_IN_CEILF BUILT_IN_CEIL BUILT_IN_CEILL IFN_CEIL)
> >> + bf (BUILT_IN_CEILF BUILT_IN_CEIL BUILT_IN_CEILL IFN_CEIL
> >> + BUILT_IN_FLOORF BUILT_IN_FLOOR BUILT_IN_FLOORL IFN_FLOOR)
> >> + floor (BUILT_IN_FLOORF BUILT_IN_FLOOR BUILT_IN_FLOORL IFN_FLOOR
> >> + BUILT_IN_FLOORF BUILT_IN_FLOOR BUILT_IN_FLOORL IFN_FLOOR)
> >> + ceil (BUILT_IN_CEILF BUILT_IN_CEIL BUILT_IN_CEILL IFN_CEIL
> >> + BUILT_IN_CEILF BUILT_IN_CEIL BUILT_IN_CEILL IFN_CEIL)
> >> + (simplify
> >> + (cond (op:c (minus:s SSA_NAME@0 (floor SSA_NAME@0))
> >> + (minus:s (ceil SSA_NAME@0) SSA_NAME@0))
> >> + (bt SSA_NAME@0) (bf SSA_NAME@0))
> >> + (if (!HONOR_SIGNED_ZEROS (type) && !HONOR_SIGN_DEPENDENT_ROUNDING
> >> (type))
> >> + (floor (plus @0 { build_real (type, dconsthalf); })))))
> >> +
> >> (if (flag_unsafe_math_optimizations)
> >> /* Simplify (C / x op 0.0) to x op 0.0 for C != 0, C != Inf/Nan.
> >> Since C / x may underflow to zero, do this only for unsafe math. */
> >> diff --git a/gcc/testsuite/gcc.dg/fold-round-1.c
> >> b/gcc/testsuite/gcc.dg/fold-round-1.c
> >> new file mode 100644
> >> index 00000000000..0d7f95429ac
> >> --- /dev/null
> >> +++ b/gcc/testsuite/gcc.dg/fold-round-1.c
> >> @@ -0,0 +1,56 @@
> >> +/* { dg-do compile } */
> >> +/* { dg-options "-Ofast" } */
> >> +
> >> +extern void link_error (void);
> >> +
> >> +#define TEST_ROUND(TYPE, FFLOOR, FCEIL)
> >> \
> >> + void round_##FFLOOR##_1 (TYPE x)
> >> \
> >> + {
> >> \
> >> + TYPE t1 = 0;
> >> \
> >> + TYPE t2 = __builtin_##FFLOOR (x + 0.5);
> >> \
> >> + if ((x - __builtin_##FFLOOR (x)) < (__builtin_##FCEIL (x) - x))
> >> \
> >> + t1 = __builtin_##FFLOOR (x);
> >> \
> >> + else
> >> \
> >> + t1 = __builtin_##FCEIL (x);
> >> \
> >> + if (t1 != t2)
> >> \
> >> + link_error ();
> >> \
> >> + }
> >> \
> >> + void round_##FFLOOR##_2 (TYPE x)
> >> \
> >> + {
> >> \
> >> + TYPE t1 = 0;
> >> \
> >> + TYPE t2 = __builtin_##FFLOOR (x + 0.5);
> >> \
> >> + if ((__builtin_##FCEIL (x) - x) > (x - __builtin_##FFLOOR (x)))
> >> \
> >> + t1 = __builtin_##FFLOOR (x);
> >> \
> >> + else
> >> \
> >> + t1 = __builtin_##FCEIL (x);
> >> \
> >> + if (t1 != t2)
> >> \
> >> + link_error ();
> >> \
> >> + }
> >> \
> >> + void round_##FFLOOR##_3 (TYPE x)
> >> \
> >> + {
> >> \
> >> + TYPE t1 = 0;
> >> \
> >> + TYPE t2 = __builtin_##FFLOOR (x + 0.5);
> >> \
> >> + if ((__builtin_##FCEIL (x) - x) <= (x - __builtin_##FFLOOR (x)))
> >> \
> >> + t1 = __builtin_##FCEIL (x);
> >> \
> >> + else
> >> \
> >> + t1 = __builtin_##FFLOOR (x);
> >> \
> >> + if (t1 != t2)
> >> \
> >> + link_error ();
> >> \
> >> + }
> >> \
> >> + void round_##FFLOOR##_4 (TYPE x)
> >> \
> >> + {
> >> \
> >> + TYPE t1 = 0;
> >> \
> >> + TYPE t2 = __builtin_##FFLOOR (x + 0.5);
> >> \
> >> + if ((x - __builtin_##FFLOOR (x)) >= (__builtin_##FCEIL (x) - x))
> >> \
> >> + t1 = __builtin_##FCEIL (x);
> >> \
> >> + else
> >> \
> >> + t1 = __builtin_##FFLOOR (x);
> >> \
> >> + if (t1 != t2)
> >> \
> >> + link_error ();
> >> \
> >> + }
> >> +
> >> +TEST_ROUND (float, floorf, ceilf)
> >> +TEST_ROUND (double, floor, ceil)
> >> +TEST_ROUND (long double, floorl, ceill)
> >> +
> >> +/* { dg-final { scan-assembler-not "link_error" } } */
> >>
>
>
--
Richard Biener <[email protected]>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
