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From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/103008] poor inlined builtin_fmod on x86_64
Date: Sat, 12 Feb 2022 22:07:31 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103008

--- Comment #14 from Uro=C5=A1 Bizjak <ubizjak at gmail dot com> ---
Created attachment 52428
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D52428&action=3Dedit
Proposed patch

The attached patch implements:

fmod (a, p) =3D a - trunc (a/p) * p
drem (a, p) =3D a - roundeven (a/p) * p

using SSE4 round instruction (and uses fnma when available).

Timings with Polyhedron ac.f90 on IvyBridge-E, Fedora-34, glibc 2.33-21.fc34

-Ofast:
       6,150082000 seconds user

-Ofast -mno-80387:
      18,354654000 seconds user

-Ofast -msse4:
       5,722511000 seconds user=