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/89213] Optimize V2DI shifts by a constant on power8 & above systems. Date: Wed, 18 Sep 2024 01:06:06 +0000 [thread overview] Message-ID: <bug-89213-4-t9kodAkMCP@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-89213-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89213 --- Comment #9 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Michael Meissner <meissner@gcc.gnu.org>: https://gcc.gnu.org/g:9a07ac151327f61963b092062eb8566dd0c6f0cd commit r15-3676-g9a07ac151327f61963b092062eb8566dd0c6f0cd Author: Michael Meissner <meissner@linux.ibm.com> Date: Tue Sep 17 21:05:27 2024 -0400 PR 89213: Add better support for shifting vectors with 64-bit elements This patch fixes PR target/89213 to allow better code to be generated to do constant shifts of V2DI/V2DF vectors. Previously GCC would do constant shifts of vectors with 64-bit elements by using: XXSPLTIB 32,4 VEXTSB2D 0,0 VSRAD 2,2,0 I.e., the PowerPC does not have a VSPLTISD instruction to load -15..14 for the 64-bit shift count in one instruction. Instead, it would need to load a byte and then convert it to 64-bit. With this patch, GCC now realizes that the vector shift instructions will look at the bottom 6 bits for the shift count, and it can use either a VSPLTISW or XXSPLTIB instruction to load the shift count. 2024-09-17 Michael Meissner <meissner@linux.ibm.com> gcc/ PR target/89213 * config/rs6000/altivec.md (UNSPEC_VECTOR_SHIFT): New unspec. (VSHIFT_MODE): New mode iterator. (vshift_code): New code iterator. (vshift_attr): New code attribute. (altivec_<mode>_<vshift_attr>_const): New pattern to optimize vector long long/int shifts by a constant. (altivec_<mode>_shift_const): New helper insn to load up a constant used by the shift operation. * config/rs6000/predicates.md (vector_shift_constant): New predicate. gcc/testsuite/ PR target/89213 * gcc.target/powerpc/pr89213.c: New test. * gcc.target/powerpc/vec-rlmi-rlnm.c: Update instruction count.
prev parent reply other threads:[~2024-09-18 1:06 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-89213-4@http.gcc.gnu.org/bugzilla/> 2024-08-12 21:45 ` meissner at gcc dot gnu.org 2024-08-12 21:57 ` meissner at gcc dot gnu.org 2024-09-18 1:06 ` cvs-commit at gcc dot gnu.org [this message]
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-89213-4-t9kodAkMCP@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).