Re: Cygwin 32bit: Can't use gcc -mfpmath=sse

["Václav Haisman" <vhaisman@gmail.com>]

On 10 September 2015 at 01:30, HK wrote:
> I've just run across this strange behavior on a recent 32bit installation:
>
>  vega> cat hello.c
> #include <stdio.h>
> int main(int argc, char** argv){
> printf("hello world\n");
> }
>  vega> gcc -mfpmath=sse hello.c
> hello.c:1:0: warning: SSE instruction set disabled, using 387 arithmetics

Does it help to use `-march=native`? My hunch is that this is because
the default CPU type is set to such that does not have SSE.

>  #include <stdio.h>
>  ^
>
> Why is this? I am pretty sure this used to work in the past.  On the 64bit
> installtion it works just fine.
>
> For reference:
>
>  vega> gcc -v
> Using built-in specs.
> COLLECT_GCC=gcc
> COLLECT_LTO_WRAPPER=/usr/lib/gcc/i686-pc-cygwin/4.9.3/lto-wrapper.exe
> Target: i686-pc-cygwin
> Configured with:
> /cygdrive/i/szsz/tmpp/gcc/gcc-4.9.3-1.i686/src/gcc-4.9.3/configure
> --srcdir=/cygdrive/i/szsz/tmpp/gcc/gcc-4.9.3-1.i686/src/gcc-4.9.3
> --prefix=/usr --exec-prefix=/usr --localstatedir=/var --sysconfdir=/etc
> --docdir=/usr/share/doc/gcc --htmldir=/usr/share/doc/gcc/html -C
> --build=i686-pc-cygwin --host=i686-pc-cygwin --target=i686-pc-cygwin
> --without-libiconv-prefix --without-libintl-prefix --libexecdir=/usr/lib
> --enable-shared --enable-shared-libgcc --enable-static
> --enable-version-specific-runtime-libs --enable-bootstrap
> --enable-__cxa_atexit --with-dwarf2 --with-arch=i686 --with-tune=generic
> --disable-sjlj-exceptions
> --enable-languages=ada,c,c++,fortran,java,lto,objc,obj-c++ --enable-graphite
> --enable-threads=posix --enable-libatomic --enable-libgomp --disable-libitm
> --enable-libquadmath --enable-libquadmath-support --enable-libssp
> --enable-libada --enable-libjava --enable-libgcj-sublibs --disable-java-awt
> --disable-symvers --with-ecj-jar=/usr/share/java/ecj.jar --with-gnu-ld
> --with-gnu-as --with-cloog-include=/usr/include/cloog-isl
> --without-libiconv-prefix --without-libintl-prefix --with-system-zlib
> --enable-linker-build-id
> Thread model: posix
> gcc version 4.9.3 (GCC)
>  vega>


-- 
VH

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