public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/114269] [14 Regression] Multiple 3-27% exec time regressions of 434.zeusmp since r14-9193-ga0b1798042d033 Date: Fri, 08 Mar 2024 12:23:58 +0000 [thread overview] Message-ID: <bug-114269-4-S4HWJTF8UJ@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-114269-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114269 --- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> --- The following is a C testcase for a case where ranges will not help: void foo (int *a, long js, long je, long is, long ie, long ks, long ke, long xi, long xj) { for (long j = js; j < je; ++j) for (long i = is; i < ie; ++i) for (long k = ks; k < ke; ++k) a[i + j*xi + k*xi*xj] = 5; } SCEV analysis result before/after shows issues. When you re-order the loops so the fast increment goes innermost this doesn't make a difference for vectorization though. In the order above we now require (emulated) gather which with SSE didn't work out and previously we used strided stores. The reason seems to be that when analyzing k*xi*xj the first multiply yields (long int) {(unsigned long) ks_21(D) * (unsigned long) xi_24(D), +, (unsigned long) xi_24(D)}_3 but when then asking to fold the multiply by xj we fail as we run into tree chrec_fold_multiply (tree type, tree op0, tree op1) { ... CASE_CONVERT: if (tree_contains_chrecs (op0, NULL)) return chrec_dont_know; /* FALLTHRU */ but this case is somewhat odd as all other unhandled cases simply run into fold_build2. This possibly means we'd never build other ops with CHREC operands. This was added for PR42326. I think we can handle sign-conversions from unsigned just fine, chrec_fold_plus does such thing already (but it misses one case). Doing this restores things to some extent. I'm testing this as an intermediate step before considering reversion of the change.
next prev parent reply other threads:[~2024-03-08 12:23 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-03-07 15:30 [Bug tree-optimization/114269] New: " pheeck at gcc dot gnu.org 2024-03-08 8:18 ` [Bug tree-optimization/114269] " rguenth at gcc dot gnu.org 2024-03-08 10:08 ` xry111 at gcc dot gnu.org 2024-03-08 10:25 ` rguenth at gcc dot gnu.org 2024-03-08 12:23 ` rguenth at gcc dot gnu.org [this message] 2024-03-08 13:41 ` cvs-commit at gcc dot gnu.org 2024-03-08 13:41 ` rguenth at gcc dot gnu.org 2024-03-12 12:48 ` [Bug tree-optimization/114269] [14 Regression] Multiple 3-6% " pheeck at gcc dot gnu.org 2024-03-15 15:01 ` law at gcc dot gnu.org 2024-03-19 12:12 ` cvs-commit at gcc dot gnu.org 2024-03-19 12:15 ` rguenth at gcc dot gnu.org
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-114269-4-S4HWJTF8UJ@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).