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From: "segher at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/97142] __builtin_fmod not optimized on POWER
Date: Tue, 13 Apr 2021 16:26:45 +0000 [thread overview]
Message-ID: <bug-97142-4-KlhnjTLThy@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-97142-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97142
--- Comment #11 from Segher Boessenkool <segher at gcc dot gnu.org> ---
(In reply to luoxhu from comment #10)
> If not built with fast-math, gimple_has_side_effects will return true and
> cause the expand_call_stmt fail to expand the "_1 = fmod (x_2(D), y_3(D));"
> to internal function. X86 also produces "bl fmod" for O3 build.
>
>
> xlF expands the fmod to below ASM, no FMA generated?
>
>
> 0000000010000900 <ggl>:
> 10000900: 8c 03 01 10 vspltisw v0,1
> 10000904: 00 00 24 c8 lfd f1,0(r4)
> 10000908: 00 00 03 c8 lfd f0,0(r3)
> 1000090c: e2 03 40 f0 xvcvsxwdp vs2,vs32
> 10000910: c0 09 62 f0 xsdivdp vs3,vs2,vs1
> 10000914: 80 19 80 f0 xsmuldp vs4,vs0,vs3
> 10000918: 64 21 a0 f0 xsrdpiz vs5,vs4
> 1000091c: 88 2d 01 f0 xsnmsubadp vs0,vs1,vs5
> 10000920: 18 00 20 fc frsp f1,f0
> 10000924: 20 00 80 4e blr
xsnmsubadp is an FMA. Multiply-subtract in this case, but that is just
a sign switch -- I often say FMA for all of fmadd, fnmadd, fnmsub, fmsub,
and their VSX counterparts. "Anything that does a multiply-type operation
followed by an addition-type operation". (And often call integer MADs
"FMA" as well, which is totally wrong, but :-) )
next prev parent reply other threads:[~2021-04-13 16:26 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-21 10:57 [Bug target/97142] New: " fx at gnu dot org
2020-09-21 11:24 ` [Bug target/97142] " rguenth at gcc dot gnu.org
2020-09-21 11:26 ` rguenth at gcc dot gnu.org
2020-09-21 14:42 ` bergner at gcc dot gnu.org
2020-09-21 14:45 ` fx at gnu dot org
2020-09-21 14:47 ` fx at gnu dot org
2020-09-21 17:52 ` segher at gcc dot gnu.org
2020-09-21 18:10 ` bergner at gcc dot gnu.org
2020-09-21 19:33 ` segher at gcc dot gnu.org
2020-09-21 21:54 ` bergner at gcc dot gnu.org
2021-04-13 6:24 ` luoxhu at gcc dot gnu.org
2021-04-13 16:26 ` segher at gcc dot gnu.org [this message]
2021-05-27 0:54 ` luoxhu at gcc dot gnu.org
2021-09-02 22:05 ` bergner at gcc dot gnu.org
2021-09-02 22:38 ` segher at gcc dot gnu.org
2021-09-03 2:33 ` luoxhu at gcc dot gnu.org
2021-09-07 1:29 ` cvs-commit at gcc dot gnu.org
2021-09-07 17:58 ` bergner at gcc dot gnu.org
2021-09-07 19:34 ` segher at gcc dot gnu.org
2021-09-07 21:20 ` segher at gcc dot gnu.org
2021-09-14 5:33 ` cvs-commit at gcc dot gnu.org
2021-09-14 5:34 ` cvs-commit at gcc dot gnu.org
2021-09-14 5:36 ` luoxhu at gcc dot gnu.org
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