http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55925
Bug #: 55925 Summary: Unrecognized command line option '-mfxsr' when building x86_64-w64-mingw32 native compiler Classification: Unclassified Product: gcc Version: 4.8.0 Status: UNCONFIRMED Severity: major Priority: P3 Component: other AssignedTo: unassig...@gcc.gnu.org ReportedBy: lailavrazda1...@gmail.com When building a native x86_64-w64-mingw32 compiler using a 4.7.2 cross compiler, I get the following: x86_64-w64-mingw32-gcc -L/root/win64-build/native/x86_64-w64-mingw32/lib -L/root/win64-build/native/mingw/lib -isystem /root/win64-build/native/x86_64-w64-mingw32/include -isystem /root/win64-build/native/mingw/include -g -O2 -O2 -g -O2 -DIN_GCC -W -Wall -Wno-narrowing -Wwrite-strings -Wcast-qual -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition -isystem ./include -g -DIN_LIBGCC2 -fbuilding-libgcc -fno-stack-protector -I. -I. -I../.././gcc -I../../../gcc-4.8.0/libgcc -I../../../gcc-4.8.0/libgcc/. -I../../../gcc-4.8.0/libgcc/../gcc -I../../../gcc-4.8.0/libgcc/../include -I../../../gcc-4.8.0/libgcc/config/libbid -DENABLE_DECIMAL_BID_FORMAT -DHAVE_CC_TLS -DUSE_EMUTLS -o crtfastmath.o -MT crtfastmath.o -MD -MP -MF crtfastmath.dep -mfxsr -msse -c ../../../gcc-4.8.0/libgcc/config/i386/crtfastmath.c x86_64-w64-mingw32-gcc: error: unrecognized command line option '-mfxsr' make[2]: *** [crtfastmath.o] Error 1 make[2]: Leaving directory `/root/win64-build/src/gcc-build/x86_64-w64-mingw32/libgcc' make[1]: *** [all-target-libgcc] Error 2 make[1]: Leaving directory `/root/win64-build/src/gcc-build' make: *** [all] Error 2 I can't find any documentation at all on this '-mfxsr' option. What is it, and why is it being used here?