public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "nmiell at comcast dot net" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/41464] New: vector loads are unnecessarily split into high and low loads Date: Thu, 24 Sep 2009 23:14:00 -0000 [thread overview] Message-ID: <bug-41464-10309@http.gcc.gnu.org/bugzilla/> (raw) gcc (GCC) 4.4.1 20090725 (Red Hat 4.4.1-2) The testcase (built with -Wall -O3): #include <math.h> void MulPi(float * __attribute__((aligned(16))) i, float * __attribute__((aligned(16))) f, int n) { for (int j = 0; j < n; j++) f[j] = (float) M_PI * i[j]; } produces the following for the vectorized version of the loop: .L7: movaps %xmm1, %xmm0 # zero XMM0 incl %ecx movlps (%rdi,%rax), %xmm0 # load the low half into XMM0 movhps 8(%rdi,%rax), %xmm0 # load the high half into XMM0 mulps %xmm2, %xmm0 # multiply by pi movaps %xmm0, (%rsi,%rax) # store to memory addq $16, %rax cmpl %r8d, %ecx jb .L7 -- Summary: vector loads are unnecessarily split into high and low loads Product: gcc Version: 4.4.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: nmiell at comcast dot net GCC build triplet: x86_64-linux-gnu GCC host triplet: x86_64-linux-gnu GCC target triplet: x86_64-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41464
next reply other threads:[~2009-09-24 23:14 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2009-09-24 23:14 nmiell at comcast dot net [this message] 2009-09-25 9:06 ` [Bug tree-optimization/41464] " rguenth at gcc dot gnu dot org 2009-09-25 17:12 ` nmiell at comcast dot net 2009-09-25 17:34 ` ubizjak at gmail dot com 2009-09-27 8:06 ` irar at il dot ibm dot com 2009-09-27 9:43 ` rguenther at suse dot de 2009-09-27 9:56 ` irar at il dot ibm dot com 2010-01-24 11:52 ` rguenth at gcc dot gnu dot org 2010-01-24 12:10 ` rguenth at gcc dot gnu dot org 2010-02-04 20:29 ` bredelin at ucla dot edu
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-41464-10309@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).