public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/104345] [12 Regression] "nvptx: Transition nvptx backend to STORE_FLAG_VALUE = 1" patch made some code generation worse Date: Thu, 10 Feb 2022 08:02:49 +0000 [thread overview] Message-ID: <bug-104345-4-akb2cyK0XS@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-104345-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104345 --- Comment #11 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Tom de Vries <vries@gcc.gnu.org>: https://gcc.gnu.org/g:6d98e83b2c919bd9fba2c61333d613bafc37357f commit r12-7168-g6d98e83b2c919bd9fba2c61333d613bafc37357f Author: Roger Sayle <roger@nextmovesoftware.com> Date: Tue Feb 8 20:56:55 2022 +0100 nvptx: Tweak constraints on copysign instructions Many thanks to Thomas Schwinge for confirming my hypothesis that the register usage regression, PR target/104345, is solely due to libgcc's _muldc3 function. In addition to the isinf functionality in the previously proposed nvptx patch at https://gcc.gnu.org/pipermail/gcc-patches/2022-January/588453.html which significantly reduces the number of instructions in _muldc3, the patch below further reduces both the number of instructions and the number of explicitly declared registers, by permitting floating point constant immediate operands in nvptx's copysign instruction. Fingers-crossed, the combination with all of the previous proposed nvptx patches improves things. Ultimately, increasing register usage from 50 to 51 registers, reducing the number of concurrent threads by ~2%, can easily be countered if we're now executing significantly fewer instructions in each kernel, for a net performance win. This patch has been tested on nvptx-none hosted on x86_64-pc-linux-gnu with a "make" and "make -k check" with no new failures. gcc/ChangeLog: * config/nvptx/nvptx.md (copysign<mode>3): Allow immediate floating point constants as operands 1 and/or 2.
next prev parent reply other threads:[~2022-02-10 8:02 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-02-02 14:10 [Bug target/104345] New: nvptx: "regression" after "nvptx: Transition nvptx backend to STORE_FLAG_VALUE = 1" tschwinge at gcc dot gnu.org 2022-02-02 14:26 ` [Bug target/104345] " roger at nextmovesoftware dot com 2022-02-02 22:37 ` [Bug target/104345] [12 Regression] "nvptx: Transition nvptx backend to STORE_FLAG_VALUE = 1" patch made some code generation worse pinskia at gcc dot gnu.org 2022-02-03 14:17 ` vries at gcc dot gnu.org 2022-02-03 21:09 ` roger at nextmovesoftware dot com 2022-02-08 11:53 ` tschwinge at gcc dot gnu.org 2022-02-08 11:54 ` tschwinge at gcc dot gnu.org 2022-02-08 11:55 ` tschwinge at gcc dot gnu.org 2022-02-08 11:57 ` tschwinge at gcc dot gnu.org 2022-02-08 12:33 ` tschwinge at gcc dot gnu.org 2022-02-08 15:36 ` tschwinge at gcc dot gnu.org 2022-02-10 8:02 ` cvs-commit at gcc dot gnu.org 2022-02-10 8:02 ` cvs-commit at gcc dot gnu.org [this message] 2022-03-02 12:10 ` roger at nextmovesoftware dot com
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=bug-104345-4-akb2cyK0XS@http.gcc.gnu.org/bugzilla/ \ --to=gcc-bugzilla@gcc.gnu.org \ --cc=gcc-bugs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).