public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "philipp.gschwandtner at uibk dot ac.at" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/64689] New: tree-vectorize generates wrong code with inlined function - minimum working example included Date: Tue, 20 Jan 2015 13:32:00 -0000 [thread overview] Message-ID: <bug-64689-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64689 Bug ID: 64689 Summary: tree-vectorize generates wrong code with inlined function - minimum working example included Product: gcc Version: 4.9.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: philipp.gschwandtner at uibk dot ac.at Created attachment 34500 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34500&action=edit minimum working example The tree vectorizer in gcc 4.7-4.9 appears to generate semantically incorrect code for the particular case clarified in the attached minimum working example. gcc 4.6.3 does not show this issue. In gcc 4.7.3 only one of the checks fails, in gcc 4.8.3 and 4.9.2 both of them fail (as these versions also seem to recognize case A as vectorizable). Testing was performed on an Intel Xeon E5-2699 v3 Haswell CPU running a 3.10.0-123.13.1.el7.x86_64 Linux kernel. Compile with: gcc test.c -o test -O3 -std=c99 -pedantic -Wall -Wextra -fwrapv -fno-strict-aliasing Expected output (equals gcc 4.6.3 output): Checking case A: EQUAL! Checking case B: EQUAL! Actual output (for gcc 4.8.3 and 4.9.2): Checking case A: NOT EQUAL! C1: -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, C2: -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, Checking case B: NOT EQUAL! C1: -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, -2 0i, C2: -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, -1 0i, Above output is produced when compiled with gcc 4.9.2 and 4.8.3. For gcc 4.7.3 the check for case A succeeds while the check for case B still fails.
next reply other threads:[~2015-01-20 13:32 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-01-20 13:32 philipp.gschwandtner at uibk dot ac.at [this message] 2015-01-20 14:10 ` [Bug tree-optimization/64689] " trippels at gcc dot gnu.org 2015-01-21 9:33 ` philipp.gschwandtner at uibk dot ac.at 2015-01-21 9:38 ` trippels 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-64689-4@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).