$ cat hello.c int main() { return 0; } $ gcc -g -ffast-math hello.c $ gdb ./a.out GNU gdb 6.3-debian Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i386-linux"...Using host libthread_db library "/lib/tls/libthread_db.so.1".
(gdb) r Starting program: /home/ig25/Krempel/a.out Program received signal SIGSEGV, Segmentation fault. 0x08048469 in set_fast_math () at ../../gcc-4.1/gcc/config/i386/crtfastmath.c:70 70 __builtin_ia32_ldmxcsr (mxcsr); (gdb) q The program is running. Exit anyway? (y or n) y $ cat /proc/cpuinfo processor : 0 vendor_id : AuthenticAMD cpu family : 6 model : 8 model name : AMD Athlon(TM) XP 2600+ stepping : 1 cpu MHz : 2083.203 cache size : 256 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmovpat pse36 mmx fxsr sse syscall mmxext 3dnowext 3dnow bogomips : 4128.76 $ gcc -v Using built-in specs. Target: i686-pc-linux-gnu Configured with: ../gcc-4.1/configure --prefix=/home/ig25 --enable-languages=c,f95 Thread model: posix gcc version 4.1.0 20050811 (experimental) This shows up as a regression in the gfortran testsuite: Running /home/ig25/gcc-4.1/gcc/testsuite/gfortran.dg/dg.exp ... FAIL: gfortran.dg/g77/20010216-1.f -O0 execution test FAIL: gfortran.dg/g77/20010216-1.f -O1 execution test FAIL: gfortran.dg/g77/20010216-1.f -O2 execution test FAIL: gfortran.dg/g77/20010216-1.f -O3 -fomit-frame-pointer execution test FAIL: gfortran.dg/g77/20010216-1.f -O3 -fomit-frame-pointer -funroll-loops execution test FAIL: gfortran.dg/g77/20010216-1.f -O3 -fomit-frame-pointer -funroll-all-loops-finline-functions execution test FAIL: gfortran.dg/g77/20010216-1.f -O3 -g execution test FAIL: gfortran.dg/g77/20010216-1.f -Os execution test -- Summary: [4.1 regression] -ffast-math startup broken on i686 (maybe Athlon-xp) Product: gcc Version: 4.1.0 Status: UNCONFIRMED Keywords: wrong-code Severity: normal Priority: P2 Component: target AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: tkoenig at gcc dot gnu dot org CC: gcc-bugs at gcc dot gnu dot org GCC target triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23360