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From: "mathias at gaunard dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/55184] New: Invalid codegen with vectors and casts
Date: Fri, 02 Nov 2012 22:33:00 -0000 [thread overview]
Message-ID: <bug-55184-4@http.gcc.gnu.org/bugzilla/> (raw)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55184
Bug #: 55184
Summary: Invalid codegen with vectors and casts
Classification: Unclassified
Product: gcc
Version: 4.6.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: mathias@gaunard.com
Created attachment 28600
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28600
Testcase
On x86-64, when 128-bit vectors of long or unsigned long are aliased, an
invalid optimization seems to occur and causes only the first element of the
vector to be modified.
Output is correct when compiled without optimization, but fails with -O1 or
greater. Usage of -fno-strict-aliasing doesn't change anything.
The problem doesn't seem to appear in the 4.4, 4.5 and 4.7 series.
Nevertheless I'd like to know all the cases it affects and whether there is a
workaround.
next reply other threads:[~2012-11-02 22:33 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-02 22:33 mathias at gaunard dot com [this message]
2012-11-02 23:08 ` [Bug target/55184] [4.6 Regression] " pinskia at gcc dot gnu.org
2012-11-03 0:30 ` mathias at gaunard dot com
2012-11-04 14:14 ` mikpe at it dot uu.se
2012-11-04 17:58 ` mathias at gaunard dot com
2012-11-04 18:01 ` mathias at gaunard dot com
2012-11-04 21:24 ` mikpe at it dot uu.se
2013-04-12 16:17 ` jakub at gcc dot gnu.org
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