http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57657
Jorge Aparicio <jorge.aparicio.r at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jorge.aparicio.r at gmail dot
com
--- Comment #1 from Jorge Aparicio <jorge.aparicio.r at gmail dot com> ---
I can confirm this gcc-4.8.1 regression on three different Intel CPUs (core i3
2nd gen, core i5 1rst gen and core i7 4th gen), but the regression actually
comes from gcc-4.8.0
CONCLUSION:
gcc-4.8.0 reports the correct cache sizes when -march=native is used
gcc-4.8.1 always reports 1) l1 cache size = 0, 2) l1 line cache size = 0 and 3)
l2 cache size = 256; when -march=native is used
OBSERVATIONS:
#### Processor 1 ####
$ lscpu | grep 'name\|cache'
Model name: Intel(R) Core(TM) i7-4702MQ CPU @ 2.20GHz
L1d cache: 32K
L1i cache: 32K
L2 cache: 256K
L3 cache: 6144K
$ gcc 4.8.0 -march=native -E -v - </dev/null 2>&1 | grep cc1
... --param l1-cache-size=32 --param l1-cache-line-size=64 --param
l2-cache-size=6144 ...
$ gcc 4.8.1 -march=native -E -v - </dev/null 2>&1 | grep cc1
... --param l1-cache-size=0 --param l1-cache-line-size=0 --param
l2-cache-size=256 ...
#### Processor 2 ####
$ lscpu | grep 'name\|cache'
Model name: Intel(R) Core(TM) i5 CPU 750 @ 2.67GHz
L1d cache: 32K
L1i cache: 32K
L2 cache: 256K
L3 cache: 8192K
$ gcc-4.8.0 -march=native -E -v - </dev/null 2>&1 | grep cc1
... --param l1-cache-size=32 --param l1-cache-line-size=64 --param
l2-cache-size=8192 ...
$ gcc 4.8.1 -march=native -E -v - </dev/null 2>&1 | grep cc1
... --param l1-cache-size=0 --param l1-cache-line-size=0 --param
l2-cache-size=256 ...
#### Processor 3 ####
$ lscpu | grep 'name\|cache'
Model name: Intel(R) Core(TM) i3-2330M CPU @ 2.20GHz
L1d cache: 32K
L1i cache: 32K
L2 cache: 256K
L3 cache: 3072K
$ gcc 4.8.0 -march=native -E -v - </dev/null 2>&1 | grep cc1
... --param l1-cache-size=32 --param l1-cache-line-size=64 --param
l2-cache-size=3072 ...
$ gcc 4.8.1 -march=native -E -v - </dev/null 2>&1 | grep cc1
... --param l1-cache-size=0 --param l1-cache-line-size=0 --param
l2-cache-size=256 ...
#### GCC version information ####
$ gcc-4.8.1 -v
Using built-in specs.
COLLECT_GCC=gcc-4.8.1
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.8.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-4.8.1/configure --disable-libssp --disable-multilib
--enable-version-specific-runtime-libs --enable-libmudflap --prefix=/usr
--bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.8.1
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.1/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.1
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.1/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.1/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.1/include/g++-v4.8
--enable-__cxa_atexit --enable-clocale=gnu --host=x86_64-pc-linux-gnu
--build=x86_64-pc-linux-gnu --disable-ppl --disable-cloog --with-system-zlib
--enable-obsolete --disable-werror --enable-secureplt --disable-lto
--with-bugurl=http://bugs.funtoo.org --with-pkgversion='Funtoo 4.8.1'
--with-mpfr-include=/var/tmp/portage/sys-devel/gcc-4.8.1/work/gcc-4.8.1/mpfr/src
--with-mpfr-lib=/var/tmp/portage/sys-devel/gcc-4.8.1/work/objdir/mpfr/src/.libs
--enable-libstdcxx-time --enable-libgomp --enable-languages=c,c++,fortran
--disable-libgcj --disable-esp
Thread model: posix
gcc version 4.8.1 (Funtoo 4.8.1)
$ gcc-4.8.0 -v
Using built-in specs.
COLLECT_GCC=gcc-4.8.0
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.8.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /var/tmp/portage/sys-devel/gcc-4.8.0/work/gcc-4.8.0/configure
--prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.8.0
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.0/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.0
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.0/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.0/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.0/include/g++-v4
--host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --disable-altivec
--disable-fixed-point --with-ppl --with-cloog --disable-isl-version-check
--with-cloog --enable-lto --disable-nls --with-system-zlib --enable-obsolete
--disable-werror --enable-secureplt --disable-multilib --with-multilib-list=m64
--disable-libmudflap --disable-libssp --enable-libgomp
--with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.8.0/python
--enable-checking=release --disable-libgcj --enable-libstdcxx-time
--enable-languages=c,c++,fortran --enable-shared --enable-threads=posix
--enable-__cxa_atexit --enable-clocale=gnu --enable-targets=all
--with-bugurl=http://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.8.0 p1.1,
pie-0.5.5'
Thread model: posix
gcc version 4.8.0 (Gentoo 4.8.0 p1.1, pie-0.5.5)
