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From: "mathog at caltech dot edu" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/46716] New: bad code generated with -mno-sse2 -m64 Date: Tue, 30 Nov 2010 00:59:00 -0000 [thread overview] Message-ID: <bug-46716-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46716 Summary: bad code generated with -mno-sse2 -m64 Product: gcc Version: 4.4.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned@gcc.gnu.org ReportedBy: mathog@caltech.edu The following small program generates incorrect output when compiled with the flags -mno-sse2 -m64 on a 64 bit system. Output is correct for -m32 or -msse2 -m64. The problem manifests as the lower double of the second parameter passed into test() being replaced by the value of the second double from the first parameter. % cat /etc/release Mandriva Linux release 2010.0 (Official) for x86_64 % cat /proc/cpuinfo | head -10 processor : 0 vendor_id : AuthenticAMD cpu family : 15 model : 33 model name : Dual Core AMD Opteron(tm) Processor 280 stepping : 2 cpu MHz : 1000.000 cache size : 1024 KB physical id : 0 siblings : 2 % gcc --version gcc (GCC) 4.4.1 example: % gcc -msse -mno-sse2 -I. -m64 -o foo gccprob2.c % ./foo s1 1.000000 2.000000 test s1 1.000000 2.000000 test s2 2.000000 2.000000 % gcc -msse -mno-sse2 -I. -m32 -o foo gccprob2.c OR % gcc -msse -msse2 -I. -m64 -o foo gccprob2.c s1 1.000000 2.000000 test s1 1.000000 2.000000 test s2 1.000000 2.000000 ************************************************* #include <stdio.h> /* for printf */ typedef double __m128d __attribute__ ((__vector_size__ (16), __may_alias__)); typedef union { __m128d x; double a[2]; } union128d; #define EMM_FLT8(a) ((double *)&(a)) void test ( __m128d s1, __m128d s2) { printf("test s1 %lf %lf\n",EMM_FLT8(s1)[0],EMM_FLT8(s1)[1]); printf("test s2 %lf %lf\n",EMM_FLT8(s2)[0],EMM_FLT8(s2)[1]); } int main (void) { __attribute__ ((aligned (16))) union128d s1; s1.a[0] = 1.0; s1.a[1] = 2.0; printf("s1 %lf %lf\n",s1.a[0],s1.a[1]); test (s1.x, s1.x); } **************************************************
next reply other threads:[~2010-11-30 0:15 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-11-30 0:59 mathog at caltech dot edu [this message] 2010-11-30 10:01 ` [Bug target/46716] [4.3/4.4/4.5/4.6 Regression] " jakub at gcc dot gnu.org 2010-11-30 12:36 ` rguenth at gcc dot gnu.org 2010-11-30 12:59 ` jakub at gcc dot gnu.org 2010-11-30 13:49 ` hjl.tools at gmail dot com 2010-11-30 17:50 ` mathog at caltech dot edu 2010-12-05 12:03 ` rguenth at gcc dot gnu.org 2011-01-03 20:28 ` rguenth at gcc dot gnu.org 2011-06-27 13:40 ` [Bug target/46716] [4.3/4.4/4.5/4.6/4.7 Regression] wrong " rguenth at gcc dot gnu.org 2012-03-02 14:36 ` [Bug target/46716] [4.4/4.5/4.6/4.7 " ubizjak at gmail dot com 2012-03-02 17:04 ` [Bug target/46716] [4.4/4.5/4.6/4.7/4.8 " uros at gcc dot gnu.org 2012-03-13 14:08 ` [Bug target/46716] [4.5/4.6/4.7/4.8 " jakub at gcc dot gnu.org 2012-07-02 12:10 ` rguenth at gcc dot gnu.org 2013-04-12 15:16 ` [Bug target/46716] [4.7/4.8/4.9 " jakub at gcc dot gnu.org 2014-01-23 7:12 ` law at redhat dot com
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