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From: "bergner at vnet dot ibm dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug regression/28170] New: Wrong result after swap byte in one word when compiled in 64-bit mode
Date: Mon, 26 Jun 2006 18:43:00 -0000 [thread overview]
Message-ID: <bug-28170-5233@http.gcc.gnu.org/bugzilla/> (raw)
A simple byte swap routine gets the wrong result when compiled with -m64 and
either -O1, -O2, -O3 or -Os.
bergner@vervain:~> /opt/biarch/gcc41-base/bin/gcc -O1 -m64 badswap.c
bergner@vervain:~> ./a.out
Before: 0x11 0x22 0x33 0x44 0x55 0x66 0x77 0x88
Result: 0x88 0x77 0x66 0x55 0x44 0x77 0x22 0x11
Expected: 0x88 0x77 0x66 0x55 0x44 0x33 0x22 0x11
Notice the third to last byte in "Result" is 0x77 when it should be 0x33. This
works with -O0 and with gcc 3.4 or earlier versions.
--
Summary: Wrong result after swap byte in one word when compiled
in 64-bit mode
Product: gcc
Version: 4.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: regression
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: bergner at vnet dot ibm dot com
GCC build triplet: powerpc64-linux
GCC host triplet: powerpc64-linux
GCC target triplet: powerpc64-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28170
next reply other threads:[~2006-06-26 18:41 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-26 18:43 bergner at vnet dot ibm dot com [this message]
2006-06-26 18:44 ` [Bug regression/28170] " bergner at vnet dot ibm dot com
2006-06-26 18:49 ` bergner at vnet dot ibm dot com
2006-06-26 18:51 ` bergner at vnet dot ibm dot com
2006-06-26 18:52 ` [Bug rtl-optimization/28170] " dje at gcc dot gnu dot org
2006-06-26 18:54 ` [Bug target/28170] [4.1/4.2 Regression] " pinskia at gcc dot gnu dot org
2006-06-26 20:46 ` pinskia at gcc dot gnu dot org
2006-06-27 1:40 ` dje at gcc dot gnu dot org
2006-06-27 1:42 ` dje at gcc dot gnu dot org
2006-06-27 1:44 ` amodra at bigpond dot net dot au
2006-06-27 1:53 ` amodra at bigpond dot net dot au
2006-07-06 14:32 ` bergner at vnet dot ibm dot com
2006-07-06 14:37 ` dje at gcc dot gnu dot org
2006-07-06 18:00 ` bergner at vnet dot ibm dot com
2006-07-06 19:00 ` dje at gcc dot gnu dot org
2006-07-09 0:34 ` steven at gcc dot gnu dot org
2006-07-10 7:21 ` [Bug target/28170] [4.1 " pinskia at gcc dot gnu dot org
2006-07-26 20:22 ` dje at gcc dot gnu dot org
2006-07-26 20:28 ` dje at gcc dot gnu dot org
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