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

[HK <hk1020@t-online.de>]

On Thu, 10 Sep 2015 13:19:04 +0200, V?clav_Haisman wrote:
> 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.
>

Yep, that did the trick. Thanks for the suggestion. Now, is this a gcc  
build
build problem?  The 64bit version doesn't need -march=native and that is on
the same computer.

>>  #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>

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