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Cyker
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Joined: 15 Jun 2006
Posts: 1746
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 Posted: Thu Jul 24, 2014 7:58 am Post subject: "gcc -march=<moocow> -Q --help=target -v" fa |
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While participating in another thread, I've noticed that | Code: | | gcc -Q --help=target -v |
doesn't seem to be working properly.
I currently have sys-devel/gcc-4.7.3-r1:4.7 installed
Can you guys check yours briefly just so I can see if it's a problem on my system or with gcc?
The two below should be fairly similar but are not:
| gcc -march=native -Q --help=target -v: |
Using built-in specs.
COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/4.7.3/gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.7.3/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /var/tmp/portage/sys-devel/gcc-4.7.3-r1/work/gcc-4.7.3/configure --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.7.3 --includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.7.3/include --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.7.3 --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.7.3/man --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.7.3/info --with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.7.3/include/g++-v4 --with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.7.3/python --enable-languages=c,c++,fortran --enable-obsolete --enable-secureplt --disable-werror --with-system-zlib --enable-nls --without-included-gettext --enable-checking=release --with-bugurl=https://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.7.3-r1 p1.4, pie-0.5.5' --enable-libstdcxx-time --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu --enable-multilib --with-multilib-list=m32,m64 --disable-altivec --disable-fixed-point --enable-targets=all --disable-libgcj --enable-libgomp --disable-libmudflap --disable-libssp --enable-lto --without-cloog --without-ppl
Thread model: posix
gcc version 4.7.3 (Gentoo 4.7.3-r1 p1.4, pie-0.5.5)
COLLECT_GCC_OPTIONS='-march=native' '-Q' '--help=target' '-v'
/usr/libexec/gcc/x86_64-pc-linux-gnu/4.7.3/cc1 -v help-dummy -march=bdver2 -mcx16 -msahf -mno-movbe -maes -mpclmul -mpopcnt -mabm -mlwp -mfma -mfma4 -mxop -mbmi -mno-bmi2 -mtbm -mavx -mno-avx2 -msse4.2 -msse4.1 -mlzcnt -mno-rdrnd -mf16c -mfsgsbase --param l1-cache-size=16 --param l1-cache-line-size=64 --param l2-cache-size=2048 -mtune=bdver2 -dumpbase help-dummy -auxbase help-dummy -version --help=target -o /tmp/ccfUVZRL.s
The following options are target specific:
-m128bit-long-double [disabled]
-m32 [disabled]
-m3dnow [disabled]
-m3dnowa [disabled]
-m64 [enabled]
-m80387 [enabled]
-m8bit-idiv [disabled]
-m96bit-long-double [enabled]
-mabi= sysv
-mabm [enabled]
-maccumulate-outgoing-args [disabled]
-maes [enabled]
-malign-double [disabled]
-malign-functions= 0
-malign-jumps= 0
-malign-loops= 0
-malign-stringops [enabled]
-mandroid [disabled]
-march= bdver2
-masm= att
-mavx [enabled]
-mavx2 [disabled]
-mavx256-split-unaligned-load [disabled]
-mavx256-split-unaligned-store [disabled]
-mbionic [disabled]
-mbmi [enabled]
-mbmi2 [disabled]
-mbranch-cost= 0
-mcld [disabled]
-mcmodel= 32
-mcpu=
-mcrc32 [disabled]
-mcx16 [enabled]
-mdispatch-scheduler [disabled]
-mf16c [enabled]
-mfancy-math-387 [enabled]
-mfentry [enabled]
-mfma [enabled]
-mfma4 [enabled]
-mforce-drap [disabled]
-mfp-ret-in-387 [enabled]
-mfpmath= 387
-mfsgsbase [enabled]
-mfused-madd
-mglibc [enabled]
-mhard-float [enabled]
-mieee-fp [enabled]
-mincoming-stack-boundary= 0
-minline-all-stringops [disabled]
-minline-stringops-dynamically [disabled]
-mintel-syntax
-mlarge-data-threshold= 0x10000
-mlwp [enabled]
-mlzcnt [enabled]
-mmmx [disabled]
-mmovbe [disabled]
-mms-bitfields [disabled]
-mno-align-stringops [disabled]
-mno-fancy-math-387 [disabled]
-mno-push-args [disabled]
-mno-red-zone [disabled]
-mno-sse4 [disabled]
-momit-leaf-frame-pointer [disabled]
-mpc32 [disabled]
-mpc64 [disabled]
-mpc80 [disabled]
-mpclmul [enabled]
-mpopcnt [enabled]
-mprefer-avx128 [disabled]
-mpreferred-stack-boundary= 0
-mpush-args [enabled]
-mrdrnd [disabled]
-mrecip [disabled]
-mrecip=
-mred-zone [enabled]
-mregparm= 0
-mrtd [disabled]
-msahf [enabled]
-msoft-float [disabled]
-msse [enabled]
-msse2 [enabled]
-msse2avx [disabled]
-msse3 [enabled]
-msse4 [enabled]
-msse4.1 [enabled]
-msse4.2 [enabled]
-msse4a [enabled]
-msse5
-msseregparm [disabled]
-mssse3 [enabled]
-mstack-arg-probe [disabled]
-mstackrealign [enabled]
-mstringop-strategy= [default]
-mtbm [enabled]
-mtls-dialect= gnu
-mtls-direct-seg-refs [enabled]
-mtune= bdver2
-muclibc [disabled]
-mveclibabi= [default]
-mvect8-ret-in-mem [disabled]
-mvzeroupper [disabled]
-mx32 [disabled]
-mxop [enabled]
Known assembler dialects (for use with the -masm-dialect= option):
att intel
Known ABIs (for use with the -mabi= option):
ms sysv
Known code models (for use with the -mcmodel= option):
32 kernel large medium small
Valid arguments to -mfpmath=:
387 387+sse 387,sse both sse sse+387 sse,387
Known vectorization library ABIs (for use with the -mveclibabi= option):
acml svml
Valid arguments to -mstringop-strategy=:
byte_loop libcall loop rep_4byte rep_8byte rep_byte unrolled_loop
Known TLS dialects (for use with the -mtls-dialect= option):
gnu gnu2
GNU C (Gentoo 4.7.3-r1 p1.4, pie-0.5.5) version 4.7.3 (x86_64-pc-linux-gnu)
compiled by GNU C version 4.7.3, GMP version 5.1.3, MPFR version 3.1.2, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
COLLECT_GCC_OPTIONS='-march=native' '-Q' '--help=target' '-v'
/usr/lib/gcc/x86_64-pc-linux-gnu/4.7.3/../../../../x86_64-pc-linux-gnu/bin/as -v --64 -o /tmp/ccdPdxJK.o /tmp/ccfUVZRL.s
GNU assembler version 2.23.2 (x86_64-pc-linux-gnu) using BFD version (Gentoo 2.23.2 p1.0) 2.23.2
|
| gcc -march=bdver2 -Q --help=target -v: |
Using built-in specs.
COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/4.7.3/gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.7.3/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /var/tmp/portage/sys-devel/gcc-4.7.3-r1/work/gcc-4.7.3/configure --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.7.3 --includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.7.3/include --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.7.3 --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.7.3/man --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.7.3/info --with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.7.3/include/g++-v4 --with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.7.3/python --enable-languages=c,c++,fortran --enable-obsolete --enable-secureplt --disable-werror --with-system-zlib --enable-nls --without-included-gettext --enable-checking=release --with-bugurl=https://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.7.3-r1 p1.4, pie-0.5.5' --enable-libstdcxx-time --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu --enable-multilib --with-multilib-list=m32,m64 --disable-altivec --disable-fixed-point --enable-targets=all --disable-libgcj --enable-libgomp --disable-libmudflap --disable-libssp --enable-lto --without-cloog --without-ppl
Thread model: posix
gcc version 4.7.3 (Gentoo 4.7.3-r1 p1.4, pie-0.5.5)
COLLECT_GCC_OPTIONS='-march=bdver2' '-Q' '--help=target' '-v'
/usr/libexec/gcc/x86_64-pc-linux-gnu/4.7.3/cc1 -v help-dummy -dumpbase help-dummy -march=bdver2 -auxbase help-dummy -version --help=target -o /tmp/ccE5eN2b.s
The following options are target specific:
-m128bit-long-double [disabled]
-m32 [disabled]
-m3dnow [disabled]
-m3dnowa [disabled]
-m64 [enabled]
-m80387 [enabled]
-m8bit-idiv [disabled]
-m96bit-long-double [enabled]
-mabi= sysv
-mabm [disabled]
-maccumulate-outgoing-args [disabled]
-maes [disabled]
-malign-double [disabled]
-malign-functions= 0
-malign-jumps= 0
-malign-loops= 0
-malign-stringops [enabled]
-mandroid [disabled]
-march= bdver2
-masm= att
-mavx [disabled]
-mavx2 [disabled]
-mavx256-split-unaligned-load [disabled]
-mavx256-split-unaligned-store [disabled]
-mbionic [disabled]
-mbmi [disabled]
-mbmi2 [disabled]
-mbranch-cost= 0
-mcld [disabled]
-mcmodel= 32
-mcpu=
-mcrc32 [disabled]
-mcx16 [disabled]
-mdispatch-scheduler [disabled]
-mf16c [disabled]
-mfancy-math-387 [enabled]
-mfentry [enabled]
-mfma [disabled]
-mfma4 [disabled]
-mforce-drap [disabled]
-mfp-ret-in-387 [enabled]
-mfpmath= 387
-mfsgsbase [disabled]
-mfused-madd
-mglibc [enabled]
-mhard-float [enabled]
-mieee-fp [enabled]
-mincoming-stack-boundary= 0
-minline-all-stringops [disabled]
-minline-stringops-dynamically [disabled]
-mintel-syntax
-mlarge-data-threshold= 0x10000
-mlwp [disabled]
-mlzcnt [disabled]
-mmmx [disabled]
-mmovbe [disabled]
-mms-bitfields [disabled]
-mno-align-stringops [disabled]
-mno-fancy-math-387 [disabled]
-mno-push-args [disabled]
-mno-red-zone [disabled]
-mno-sse4 [enabled]
-momit-leaf-frame-pointer [disabled]
-mpc32 [disabled]
-mpc64 [disabled]
-mpc80 [disabled]
-mpclmul [disabled]
-mpopcnt [disabled]
-mprefer-avx128 [disabled]
-mpreferred-stack-boundary= 0
-mpush-args [enabled]
-mrdrnd [disabled]
-mrecip [disabled]
-mrecip=
-mred-zone [enabled]
-mregparm= 0
-mrtd [disabled]
-msahf [disabled]
-msoft-float [disabled]
-msse [disabled]
-msse2 [disabled]
-msse2avx [disabled]
-msse3 [disabled]
-msse4 [disabled]
-msse4.1 [disabled]
-msse4.2 [disabled]
-msse4a [disabled]
-msse5
-msseregparm [disabled]
-mssse3 [disabled]
-mstack-arg-probe [disabled]
-mstackrealign [enabled]
-mstringop-strategy= [default]
-mtbm [disabled]
-mtls-dialect= gnu
-mtls-direct-seg-refs [enabled]
-mtune=
-muclibc [disabled]
-mveclibabi= [default]
-mvect8-ret-in-mem [disabled]
-mvzeroupper [disabled]
-mx32 [disabled]
-mxop [disabled]
Known assembler dialects (for use with the -masm-dialect= option):
att intel
Known ABIs (for use with the -mabi= option):
ms sysv
Known code models (for use with the -mcmodel= option):
32 kernel large medium small
Valid arguments to -mfpmath=:
387 387+sse 387,sse both sse sse+387 sse,387
Known vectorization library ABIs (for use with the -mveclibabi= option):
acml svml
Valid arguments to -mstringop-strategy=:
byte_loop libcall loop rep_4byte rep_8byte rep_byte unrolled_loop
Known TLS dialects (for use with the -mtls-dialect= option):
gnu gnu2
GNU C (Gentoo 4.7.3-r1 p1.4, pie-0.5.5) version 4.7.3 (x86_64-pc-linux-gnu)
compiled by GNU C version 4.7.3, GMP version 5.1.3, MPFR version 3.1.2, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
COLLECT_GCC_OPTIONS='-march=bdver2' '-Q' '--help=target' '-v'
/usr/lib/gcc/x86_64-pc-linux-gnu/4.7.3/../../../../x86_64-pc-linux-gnu/bin/as -v --64 -o /tmp/cc7Uelkz.o /tmp/ccE5eN2b.s
GNU assembler version 2.23.2 (x86_64-pc-linux-gnu) using BFD version (Gentoo 2.23.2 p1.0) 2.23.2
|
It's hard to see without a side-by-side comparison due to the wall of text, but look in particular at the -msse* stuff; In one they're listed as enabled and in the other not, even tho' the implied -march is the same!
Weird, no?
There are also some other odd anomalies; I didn't think you could use the '387 in 64-bit mode, and that -mfpmath should default to sse anyway, yet it clearly says 387 in both.
Also, -mmmx is disabled even tho' tho the chip supports it, and -fomit-frame-pointer is disabled, when the docs say it should default to on with 64-bit? |
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Cyker
Veteran
Joined: 15 Jun 2006
Posts: 1746
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| Posted: Thu Jul 24, 2014 8:32 am Post subject: |
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Ah looks like it is just a bug with gcc's display of the options; If you run | Code: | | echo 'int main() {return 0;}' > test.c && gcc -v -Q -march=native -O2 test.c -o test && rm test.c test |
or | Code: | | echo 'int main() {return 0;}' > test.c && gcc -v -Q -march=bdver2 -O2 test.c -o test && rm test.c test |
the right flags and things are listed there. |
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krinn
Watchman
Joined: 02 May 2003
Posts: 7470
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| Posted: Thu Jul 24, 2014 8:38 am Post subject: |
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It just output options set by -march
And when using native it output options set by march and option set by the detection.
It's easier to see with i686 and -m64 option
| Code: | gcc -march=corei7 -Q --help=target -v | grep 64
...
-m64 [disabled]
-mpc64 [disabled]
|
it run i686 but it output what is ok to do with corei7, so even in i686 it output -m64 as possible option to use.
| Code: | gcc -march=native -Q --help=target -v | grep 64
...
-mpc64 [disabled]
|
Now in native, it see the arch is i686, and that the -m64 is no more an option we can pick. And the option disappear.
That's why i have words with a dev that complain bug report with long CFLAGS will be drop ; well in native we could use short CFLAGS, but with distcc we must use the -march=cputype of your cpu, and then you must write every options -march=native enable, but that aren't enable per default when using -march=cputype
| Code: | gcc -march=native -Q --help=target -v | grep msse
-msse [enabled]
gcc -march=corei7 -Q --help=target -v | grep msse
-msse [disabled]
gcc -march=corei7 -Q --help=target -v -msse | grep sse
-msse [enabled]
|
Why you think coprocessor cannot be use in 64bits? |
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steveL
Watchman
Joined: 13 Sep 2006
Posts: 5153
Location: The Peanut Gallery
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| Posted: Thu Jul 24, 2014 4:53 pm Post subject: |
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| krinn wrote: | | That's why i have words with a dev that complain bug report with long CFLAGS will be drop ; well in native we could use short CFLAGS, but with distcc we must use the -march=cputype of your cpu, and then you must write every options -march=native enable, but that aren't enable per default when using -march=cputype |
Yeah that's a good point; if emerge --info shows distcc in use, that cannot apply. |
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Ant P.
Watchman
Joined: 18 Apr 2009
Posts: 6920
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| Posted: Mon Jul 28, 2014 11:07 pm Post subject: |
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Just for reference, here's what I use to expand -march=native for distcc:
| Code: | #!/bin/sh
echo $(
gcc -v -march=native -x c /dev/null 2>&1 \
| grep -- '-march' \
| ack -o --color --match "(?<=\s)-(?:m|-param )\\S+"
) |
The output's not all that long, and follows a pretty obvious pattern. (IMO anyone complaining about something so inconsequential can't be trusted to fix bugs competently anyway...) |
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