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/56918] [4.8 Regression] incorrect auto-vectorization of array initialization Date: Thu, 11 Apr 2013 11:59:00 -0000 [thread overview] Message-ID: <bug-56918-4-F6hjjuMOgC@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-56918-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56918 --- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> 2013-04-11 11:59:05 UTC --- The vectorizer does nothing wrong. The bug goes away with -fdisable-tree-vrp2 which would expose - stmp_var_.3_2 = 0 + 1; - stmp_var_.3_19 = stmp_var_.3_2 + 1; - stmp_var_.3_20 = stmp_var_.3_19 + 1; - vect_cst_.4_21 = {0, stmp_var_.3_2, stmp_var_.3_19, stmp_var_.3_20}; + stmp_var_.3_2 = 1; + stmp_var_.3_19 = 2; + stmp_var_.3_20 = 3; + vect_cst_.4_21 = { 0, 1, 2, 3 }; (ick, unfolded 0 + 1) so we expand vect_patt.11_29 = { 2, 3, 4, 5 } >> 31; vect_patt.12_30 = { -1, -1, -1, -1 } - vect_patt.11_29; vect_patt.13_32 = vect_patt.12_30 * { 3, 3, 3, 3 }; vect_patt.15_33 = { 2, 3, 4, 5 } - vect_patt.13_32; vect_var_.16_35 = vect_patt.15_33 + { 1, 1, 1, 1 }; vect_var_.18_36 = [vec_unpack_float_lo_expr] vect_var_.16_35; vect_var_.18_37 = [vec_unpack_float_hi_expr] vect_var_.16_35; MEM[(double[1024] *)&data] = vect_var_.18_36; MEM[(double[1024] *)&data + 16B] = vect_var_.18_37; _10 = data[0]; if (_10 != 3.0e+0) where I bet that unfolded constant expressions are somehow mis-handled.
next prev parent reply other threads:[~2013-04-11 11:59 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-04-11 11:04 [Bug tree-optimization/56918] New: " kretz at kde dot org 2013-04-11 11:42 ` [Bug tree-optimization/56918] [4.8 Regression] " rguenth at gcc dot gnu.org 2013-04-11 11:59 ` rguenth at gcc dot gnu.org [this message] 2013-04-11 14:43 ` jakub at gcc dot gnu.org 2013-04-11 15:20 ` jakub at gcc dot gnu.org 2013-04-12 9:13 ` jakub 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-56918-4-F6hjjuMOgC@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).