SSE instruction set disabled when i'm using -flto

Marcin Mirosław marcin@mejor.pl
Sat Nov 27 14:36:00 GMT 2010


Hello!
I've newbie question. Why , when i'm using "-flto" optimilization, i'm
getting warning:
"lto1: warning: SSE instruction set disabled, using 387 arithmetics
lto1: warning: -fprefetch-loop-arrays not supported for this target (try
-march switches)
"
?
Last lines from cimpilation log:
i686-pc-linux-gnu-gcc  -I.. -O2 -march=native -mfpmath=sse -pipe
-fprefetch-loop-arrays -fomit-frame-pointer -flto  -Wall
-I/usr/include/readline -DWITH_IOCTLD
-DIOCTLD_PATH=\"/usr/libexec/ioctld\" -DDATADIR=\"/usr/share/ekg\"
-DSYSCONFDIR=\"/etc\" ioctld.c -o ioctld -lssl -lcrypto -ldl -lz
-lgadu  -lncurses   -lreadline -ljpeg -lz -laspell  ../compat/strlcat.o
../compat/strlcpy.o
ioctld.c: In function ‘main’:
ioctld.c:209:7: warning: ignoring return value of ‘chown’, declared with
attribute warn_unused_result
lto1: warning: SSE instruction set disabled, using 387 arithmetics
lto1: warning: -fprefetch-loop-arrays not supported for this target (try
-march switches)
gmake[1]: Opuszczenie katalogu
`/var/tmp/portage/net-im/ekg-9999/work/ekg-9999/src'
>>> Source compiled.

I'm using:

$ gcc -v
Using built-in specs.
COLLECT_GCC=/usr/i686-pc-linux-gnu/gcc-bin/4.5.1/gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/i686-pc-linux-gnu/4.5.1/lto-wrapper
Target: i686-pc-linux-gnu
Configured with:
/var/tmp/portage/sys-devel/gcc-4.5.1-r1/work/gcc-4.5.1/configure
--prefix=/usr --bindir=/usr/i686-pc-linux-gnu/gcc-bin/4.5.1
--includedir=/usr/lib/gcc/i686-pc-linux-gnu/4.5.1/include
--datadir=/usr/share/gcc-data/i686-pc-linux-gnu/4.5.1
--mandir=/usr/share/gcc-data/i686-pc-linux-gnu/4.5.1/man
--infodir=/usr/share/gcc-data/i686-pc-linux-gnu/4.5.1/info
--with-gxx-include-dir=/usr/lib/gcc/i686-pc-linux-gnu/4.5.1/include/g++-v4
--host=i686-pc-linux-gnu --build=i686-pc-linux-gnu --disable-altivec
--disable-fixed-point --with-ppl --with-cloog --enable-lto --enable-nls
--without-included-gettext --with-system-zlib --disable-werror
--enable-secureplt --disable-multilib --enable-libmudflap
--disable-libssp --enable-esp --enable-libgomp --enable-cld
--with-python-dir=/share/gcc-data/i686-pc-linux-gnu/4.5.1/python
--enable-checking=release --disable-libgcj --with-arch=i686
--enable-languages=c,c++ --enable-shared --enable-threads=posix
--enable-__cxa_atexit --enable-clocale=gnu
--with-bugurl=http://bugs.gentoo.org/ --with-pkgversion='Gentoo Hardened
4.5.1-r1 p1.3, pie-0.4.5'
Thread model: posix
gcc version 4.5.1 (Gentoo Hardened 4.5.1-r1 p1.3, pie-0.4.5)

$ cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 23
model name      : Pentium(R) Dual-Core  CPU      E6300  @ 2.80GHz
stepping        : 10
cpu MHz         : 2799.998
cache size      : 2048 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 13
wp              : yes
flags           : fpu de tsc msr pae cx8 cmov pat clflush mmx fxsr sse
sse2 ss ht nx constant_tsc aperfmperf pni vmx ssse3 dts tpr_shadow vnmi
flexpriority
bogomips        : 5599.99
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:


Thank you for help.
Regards,
Marcin



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