During "bashmark" memory benchmark perfomance analyze, I found ~100x perfomance
regression between gcc 3.4.5 and gcc 4.X.
Compiler options: -march=athlon-xp -O3
test_cmd execution time:
- GCC 3.4.5: 0.43user 0.00system 0:00.44elapsed
- GCC 4.0.2: 34.83user 0.68system 0:36.09elapsed
- GCC 4.1.0: 33.86user 0.58system 0:34.96elapsed
Lurking inside assembler generation showed that GCC4 don't inline memcpy and
memset calls. (I can attach assembler code on request)
So, it looks like GCC4 inliner is broken at some point.
--------- GCC 3.4.5 output------------------------------------------
Reading specs from /usr/lib/gcc/i686-pc-linux-gnu/3.4.5/specs
Configured with: /mnt/oktet/tmp/portage/gcc-3.4.5-r1/work/gcc-3.4.5/configure
--prefix=/usr --bindir=/usr/i686-pc-linux-gnu/gcc-bin/3.4.5
--includedir=/usr/lib/gcc/i686-pc-linux-gnu/3.4.5/include
--datadir=/usr/share/gcc-data/i686-pc-linux-gnu/3.4.5
--mandir=/usr/share/gcc-data/i686-pc-linux-gnu/3.4.5/man
--infodir=/usr/share/gcc-data/i686-pc-linux-gnu/3.4.5/info
--with-gxx-include-dir=/usr/lib/gcc/i686-pc-linux-gnu/3.4.5/include/g++-v3
--host=i686-pc-linux-gnu --build=i686-pc-linux-gnu --disable-altivec
--enable-nls --without-included-gettext --with-system-zlib --disable-checking
--disable-werror --disable-libunwind-exceptions --disable-multilib
--disable-libgcj --enable-languages=c,c++,f77 --enable-shared
--enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu
Thread model: posix
gcc version 3.4.5 (Gentoo 3.4.5-r1, ssp-3.4.5-1.0, pie-8.7.9)
/usr/libexec/gcc/i686-pc-linux-gnu/3.4.5/cc1plus -E -quiet -v -D_GNU_SOURCE
test_cmd.cpp -march=athlon-xp -O3 -o test_cmd.ii
ignoring nonexistent directory
"/usr/lib/gcc/i686-pc-linux-gnu/3.4.5/../../../../i686-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/libffi
/usr/lib/gcc/i686-pc-linux-gnu/3.4.5/include/g++-v3
/usr/lib/gcc/i686-pc-linux-gnu/3.4.5/include/g++-v3/i686-pc-linux-gnu
/usr/lib/gcc/i686-pc-linux-gnu/3.4.5/include/g++-v3/backward
/usr/local/include
/usr/lib/gcc/i686-pc-linux-gnu/3.4.5/include
/usr/include
End of search list.
/usr/libexec/gcc/i686-pc-linux-gnu/3.4.5/cc1plus -fpreprocessed test_cmd.ii
-quiet -dumpbase test_cmd.cpp -march=athlon-xp -auxbase test_cmd -O3 -version
-o test_cmd.s
GNU C++ version 3.4.5 (Gentoo 3.4.5-r1, ssp-3.4.5-1.0, pie-8.7.9)
(i686-pc-linux-gnu)
compiled by GNU C version 3.4.5 (Gentoo 3.4.5, ssp-3.4.5-1.0,
pie-8.7.9).
GGC heuristics: --param ggc-min-expand=99 --param ggc-min-heapsize=129319
---------------------------------------------------
-----------GCC 4.0.2 output -----------------------
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: /mnt/oktet/tmp/portage/gcc-4.0.2-r3/work/gcc-4.0.2/configure
--prefix=/usr --bindir=/usr/i686-pc-linux-gnu/gcc-bin/4.0.2
--includedir=/usr/lib/gcc/i686-pc-linux-gnu/4.0.2/include
--datadir=/usr/share/gcc-data/i686-pc-linux-gnu/4.0.2
--mandir=/usr/share/gcc-data/i686-pc-linux-gnu/4.0.2/man
--infodir=/usr/share/gcc-data/i686-pc-linux-gnu/4.0.2/info
--with-gxx-include-dir=/usr/lib/gcc/i686-pc-linux-gnu/4.0.2/include/g++-v4
--host=i686-pc-linux-gnu --build=i686-pc-linux-gnu --disable-altivec
--disable-nls --with-system-zlib --disable-checking --disable-werror
--disable-libunwind-exceptions --disable-multilib --disable-libmudflap
--disable-libssp --disable-libgcj --enable-languages=c,c++ --enable-shared
--enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu
Thread model: posix
gcc version 4.0.2 (Gentoo 4.0.2-r3, pie-8.7.8)
/usr/libexec/gcc/i686-pc-linux-gnu/4.0.2/cc1plus -E -quiet -v -D_GNU_SOURCE
test_cmd.cpp -march=athlon-xp -O3 -fpch-preprocess -o test_cmd.ii
ignoring nonexistent directory
"/usr/lib/gcc/i686-pc-linux-gnu/4.0.2/../../../../i686-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/libffi
/usr/lib/gcc/i686-pc-linux-gnu/4.0.2/include/g++-v4
/usr/lib/gcc/i686-pc-linux-gnu/4.0.2/include/g++-v4/i686-pc-linux-gnu
/usr/lib/gcc/i686-pc-linux-gnu/4.0.2/include/g++-v4/backward
/usr/local/include
/usr/lib/gcc/i686-pc-linux-gnu/4.0.2/include
/usr/include
End of search list.
/usr/libexec/gcc/i686-pc-linux-gnu/4.0.2/cc1plus -fpreprocessed test_cmd.ii
-quiet -dumpbase test_cmd.cpp -march=athlon-xp -auxbase test_cmd -O3 -version
-o test_cmd.s
GNU C++ version 4.0.2 (Gentoo 4.0.2-r3, pie-8.7.8) (i686-pc-linux-gnu)
compiled by GNU C version 4.0.2 (Gentoo 4.0.2-r3, pie-8.7.8).
GGC heuristics: --param ggc-min-expand=99 --param ggc-min-heapsize=129319
---------------------------------------------------
----------GCC 4.1.0 output-------------------------
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: /mnt/oktet/tmp/portage/gcc-4.1.0-r2/work/gcc-4.1.0/configure
--prefix=/usr --bindir=/usr/i686-pc-linux-gnu/gcc-bin/4.1.0
--includedir=/usr/lib/gcc/i686-pc-linux-gnu/4.1.0/include
--datadir=/usr/share/gcc-data/i686-pc-linux-gnu/4.1.0
--mandir=/usr/share/gcc-data/i686-pc-linux-gnu/4.1.0/man
--infodir=/usr/share/gcc-data/i686-pc-linux-gnu/4.1.0/info
--with-gxx-include-dir=/usr/lib/gcc/i686-pc-linux-gnu/4.1.0/include/g++-v4
--host=i686-pc-linux-gnu --build=i686-pc-linux-gnu --disable-altivec
--enable-nls --without-included-gettext --with-system-zlib --disable-checking
--disable-werror --disable-libunwind-exceptions --disable-multilib
--disable-libmudflap --disable-libssp --enable-java-awt=gtk
--enable-languages=c,c++,java,objc,fortran --enable-shared
--enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu
Thread model: posix
gcc version 4.1.0 (Gentoo 4.1.0-r2, pie-8.7.8)
/usr/libexec/gcc/i686-pc-linux-gnu/4.1.0/cc1plus -E -quiet -v -D_GNU_SOURCE
test_cmd.cpp -march=athlon-xp -O3 -fpch-preprocess -o test_cmd.ii
ignoring nonexistent directory
"/usr/lib/gcc/i686-pc-linux-gnu/4.1.0/../../../../i686-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/libffi
/usr/lib/gcc/i686-pc-linux-gnu/4.1.0/include/g++-v4
/usr/lib/gcc/i686-pc-linux-gnu/4.1.0/include/g++-v4/i686-pc-linux-gnu
/usr/lib/gcc/i686-pc-linux-gnu/4.1.0/include/g++-v4/backward
/usr/local/include
/usr/lib/gcc/i686-pc-linux-gnu/4.1.0/include
/usr/include
End of search list.
/usr/libexec/gcc/i686-pc-linux-gnu/4.1.0/cc1plus -fpreprocessed test_cmd.ii
-quiet -dumpbase test_cmd.cpp -march=athlon-xp -auxbase test_cmd -O3 -version
-o test_cmd.s
GNU C++ version 4.1.0 (Gentoo 4.1.0-r2, pie-8.7.8) (i686-pc-linux-gnu)
compiled by GNU C version 4.1.0 (Gentoo 4.1.0-r2, pie-8.7.8).
GGC heuristics: --param ggc-min-expand=99 --param ggc-min-heapsize=129319
Compiler executable checksum: d3096f5bd00a04a18edac8d63d29a37f
---------------------------------------------------
--
Summary: perfomance regression between gcc 3.4.5 and 4.*
Product: gcc
Version: 4.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: regression
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: nbkolchin at gmail dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26658
