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From: "ishiura-compiler at ml dot kwansei.ac.jp" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/57131] New: Wong register assignment? Date: Wed, 01 May 2013 06:02:00 -0000 [thread overview] Message-ID: <bug-57131-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57131 Bug #: 57131 Summary: Wong register assignment? Classification: Unclassified Product: gcc Version: 4.8.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: rtl-optimization AssignedTo: unassigned@gcc.gnu.org ReportedBy: ishiura-compiler@ml.kwansei.ac.jp This miscompile occurs only on 32bit x86 (i686) target of GCC 4.8.1 (prerelease). (There is no problem with x86_64 target or GCC 4.7.3.) A dubious option is "-foptimize-register-move." $ cat error.c int main (void) { volatile int x1 = 0; volatile long long x2 = 0; volatile int x3 = 0; volatile int x4 = 1; volatile int x5 = 1; volatile long long x6 = 1; long long t = ( ( x1 * ( x2 << x3 ) ) / (x4 * x5) ) + x6 ; return (t == 1); } $ i686-pc-linux-gnu-gcc-4.8.1 error.c -O1 -fexpensive-optimizations -foptimize-register-move $ ./a.out Floating point exception (core dumped) ----- $ i686-pc-linux-gnu-gcc-4.8.1 -v Using built-in specs. COLLECT_GCC=i686-pc-linux-gnu-gcc-4.8.1 COLLECT_LTO_WRAPPER=/usr/local/i686-tools/gcc-4.8.1/libexec/gcc/i686-pc-linux-gnu/4.8.1/lto-wrapper Target: i686-pc-linux-gnu Configured with: /home/hassy-i686-linux/gcc/configure --prefix=/usr/local/i686-tools/gcc-4.8.1/ --with-gmp=/usr/local/gmp-5.1.1/ --with-mpfr=/usr/local/mpfr-3.1.2/ --with-mpc=/usr/local/mpc-1.0.1/ --disable-multilib --disable-nls --enable-languages=c Thread model: posix gcc version 4.8.1 20130428 (prerelease) (GCC)
next reply other threads:[~2013-05-01 6:02 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-05-01 6:02 ishiura-compiler at ml dot kwansei.ac.jp [this message] 2013-05-01 6:44 ` [Bug rtl-optimization/57131] [4.8/4.9 Regression] Wrong " jakub at gcc dot gnu.org 2013-05-01 7:39 ` jakub at gcc dot gnu.org 2013-05-02 3:03 ` vmakarov at redhat dot com 2013-05-02 3:16 ` pinskia at gcc dot gnu.org 2013-05-02 19:26 ` jakub at gcc dot gnu.org
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