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From: "wschmidt at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/57949] [powerpc64] Structure parameter alignment issue with vector extensions
Date: Tue, 23 Jul 2013 17:24:00 -0000	[thread overview]
Message-ID: <bug-57949-4-wuJkDOvo4i@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-57949-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57949

--- Comment #4 from Bill Schmidt <wschmidt at gcc dot gnu.org> ---
Enabling the code used for MachO/Darwin64 when targeting ABI_AIX/linux produces
much better code:

    li 9,144
    addis 8,2,.LC1@toc@ha
    lvx 0,1,9
    ld 10,.LC1@toc@l(8)
    addis 8,2,.LC2@toc@ha
    ld 9,.LC2@toc@l(8)
    ld 8,128(1)
    stvx 0,0,9
    std 8,0(10)
    blr

A properly aligned vector load is used from the parameter save area without a
copy through the local variable area.

David/Peter, two questions:

(1) Would it be reasonable to make this the new default behavior, but add a
target-specific flag (-munaligned-vect-struct-parms or something) to allow
compatibility with the existing behavior?  I doubt this comes up often, but it
probably occurs somewhere in an existing library interface.

(2) If we make a change, should it be just for Linux, or should we change code
for AIX as well?


  parent reply	other threads:[~2013-07-23 17:24 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-21 16:30 [Bug target/57949] New: " wschmidt at gcc dot gnu.org
2013-07-22 16:02 ` [Bug target/57949] " wschmidt at gcc dot gnu.org
2013-07-22 16:30 ` wschmidt at gcc dot gnu.org
2013-07-23 17:24 ` wschmidt at gcc dot gnu.org [this message]
2013-07-23 20:29 ` wschmidt at gcc dot gnu.org
2013-07-23 20:40 ` joseph at codesourcery dot com
2013-07-31  2:26 ` wschmidt at gcc dot gnu.org
2013-08-14 20:39 ` wschmidt at gcc dot gnu.org
2013-11-15 23:41 ` uweigand at gcc dot gnu.org
2014-04-04 14:05 ` wschmidt at gcc dot gnu.org

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