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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/64410] gcc 25% slower than clang 3.5 for adding complex numbers
Date: Thu, 08 Jan 2015 15:04:00 -0000	[thread overview]
Message-ID: <bug-64410-4-3lH3zQyc7y@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-64410-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64410

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 34402
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34402&action=edit
patch to pattern-detect the load/store

This pattern matches real/imagpart uses and single-use complex stores and
transforms them to component-wise accesses in forwprop.  Together we vectorize
the loop now and produce:

.L28:
        movupd  (%rbx,%rax), %xmm1
        movupd  (%r15,%rax), %xmm0
        addpd   %xmm1, %xmm0
        movups  %xmm0, 0(%r13,%rax)
        addq    $16, %rax
        cmpq    %rax, %rdx
        jne     .L28

note that we need a runtime alias check to disambiguate things (because
std::vector memory cannot be disambiguated statically) and similarly we
cannot prove sufficent alignment to use aligned loads/stores.


  parent reply	other threads:[~2015-01-08 15:04 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-64410-4@http.gcc.gnu.org/bugzilla/>
2014-12-26 10:04 ` glisse at gcc dot gnu.org
2014-12-26 11:23 ` conradsand.arma at gmail dot com
2014-12-26 13:19 ` glisse at gcc dot gnu.org
2014-12-28  0:20 ` dje at gcc dot gnu.org
2015-01-08 13:02 ` rguenth at gcc dot gnu.org
2015-01-08 14:03 ` rguenth at gcc dot gnu.org
2015-01-08 14:06 ` rguenth at gcc dot gnu.org
2015-01-08 14:36 ` glisse at gcc dot gnu.org
2015-01-08 15:04 ` rguenth at gcc dot gnu.org [this message]
2015-01-08 15:11 ` rguenth at gcc dot gnu.org
2015-01-09 11:15 ` [Bug tree-optimization/64410] " rguenth at gcc dot gnu.org
2015-01-09 11:15 ` rguenth at gcc dot gnu.org
2015-01-20 10:06 ` ro at gcc dot gnu.org
2015-01-20 10:07 ` ro at gcc dot gnu.org
2015-01-20 11:06 ` rguenth at gcc dot gnu.org
2022-11-28 22:01 ` pinskia at gcc dot gnu.org

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