https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70768
Bug ID: 70768
Summary: Increased compilation time
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jamrial at gmail dot com
Target Milestone: ---
Created attachment 38332
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38332&action=edit
Preprocessed output
The attached preprocessed output (Created from the source using GCC 5, 6 and 7
for the purpose of this ticket) takes almost twice as long to compile using GCC
6.0.1 RC and especially GCC 7.0 compared to GCC 5.3 on a linux x86_64 machine
with 2gb of RAM.
> GCC 5.3.0, ArchLinux package
[jamrial@ArchVM ~]$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-unknown-linux-gnu/5.3.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: /build/gcc/src/gcc-5-20160209/configure --prefix=/usr
--libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man
--infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++ --enable-shared
--enable-threads=posix --enable-libmpx --with-system-zlib --with-isl
--enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu
--disable-libstdcxx-pch --disable-libssp --enable-gnu-unique-object
--enable-linker-build-id --enable-lto --enable-plugin
--enable-install-libiberty --with-linker-hash-style=gnu
--enable-gnu-indirect-function --disable-multilib --disable-werror
--enable-checking=release
Thread model: posix
gcc version 5.3.0 (GCC)
[jamrial@ArchVM ~]$ time c++ -ftemplate-backtrace-limit=0 -Wall -Wextra
-pedantic -Werror -pedantic-errors -Wno-error=deprecated-declarations
-Wno-missing-field-initializers -Wno-unused-parameter -march=haswell -Ofast -g0
-std=gnu++14 -o transform_gcc5.o -c transform_gcc5.ii
real 1m13.380s
user 1m11.920s
sys 0m0.793s
[jamrial@ArchVM ~]$ time c++ -ftemplate-backtrace-limit=0 -Wall -Wextra
-pedantic -Werror -pedantic-errors -Wno-error=deprecated-declarations
-Wno-missing-field-initializers -Wno-unused-parameter -march=haswell -Ofast -g0
-std=gnu++14 -o transform_gcc6.o -c transform_gcc6.ii
real 1m32.820s
user 1m23.093s
sys 0m1.457s
[jamrial@ArchVM ~]$ time c++ -ftemplate-backtrace-limit=0 -Wall -Wextra
-pedantic -Werror -pedantic-errors -Wno-error=deprecated-declarations
-Wno-missing-field-initializers -Wno-unused-parameter -march=haswell -Ofast -g0
-std=gnu++14 -o transform_gcc7.o -c transform_gcc7.ii
real 1m31.705s
user 1m20.663s
sys 0m1.490s
> GCC 6.0.1 RC
[jamrial@ArchVM ~]$ gcc-6 -v
Using built-in specs.
COLLECT_GCC=gcc-6
COLLECT_LTO_WRAPPER=/usr/local/lib/gcc/x86_64-pc-linux-gnu/6.0.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /home/jamrial/gcc-svn/configure --prefix=/usr/local
--libdir=/usr/local/lib --libexecdir=/usr/local/lib
--mandir=/usr/local/share/man --infodir=/usr/local/share/info
--enable-languages=c,c++,lto --enable-shared --enable-threads=posix
--enable-libmpx --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch
--disable-libssp --enable-gnu-unique-object --enable-linker-build-id
--enable-lto --enable-plugin --enable-install-libiberty
--with-linker-hash-style=gnu --enable-gnu-indirect-function --disable-multilib
--disable-bootstrap --disable-werror
Thread model: posix
gcc version 6.0.1 20160415 (prerelease) (GCC)
[jamrial@ArchVM ~]$ time c++-6 -ftemplate-backtrace-limit=0 -Wall -Wextra
-pedantic -Werror -pedantic-errors -Wno-error=deprecated-declarations
-Wno-missing-field-initializers -Wno-unused-parameter -march=haswell -Ofast -g0
-std=gnu++14 -o transform_gcc5.o -c transform_gcc5.ii
real 1m14.796s
user 1m13.520s
sys 0m0.787s
[jamrial@ArchVM ~]$ time c++-6 -ftemplate-backtrace-limit=0 -Wall -Wextra
-pedantic -Werror -pedantic-errors -Wno-error=deprecated-declarations
-Wno-missing-field-initializers -Wno-unused-parameter -march=haswell -Ofast -g0
-std=gnu++14 -o transform_gcc6.o -c transform_gcc6.ii
real 2m29.020s
user 1m25.240s
sys 0m6.537s
[jamrial@ArchVM ~]$ time c++-6 -ftemplate-backtrace-limit=0 -Wall -Wextra
-pedantic -Werror -pedantic-errors -Wno-error=deprecated-declarations
-Wno-missing-field-initializers -Wno-unused-parameter -march=haswell -Ofast -g0
-std=gnu++14 -o transform_gcc7.o -c transform_gcc7.ii
real 2m27.268s
user 1m23.977s
sys 0m7.167s
> GCC 7.0
[jamrial@ArchVM ~]$ gcc-7 -v
Using built-in specs.
COLLECT_GCC=gcc-7
COLLECT_LTO_WRAPPER=/usr/local/lib/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /home/jamrial/gcc-svn/configure --prefix=/usr/local
--libdir=/usr/local/lib --libexecdir=/usr/local/lib
--mandir=/usr/local/share/man --infodir=/usr/local/share/info
--enable-languages=c,c++,lto --enable-shared --enable-threads=posix
--enable-libmpx --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch
--disable-libssp --enable-gnu-unique-object --enable-linker-build-id
--enable-lto --enable-plugin --enable-install-libiberty
--with-linker-hash-style=gnu --enable-gnu-indirect-function --disable-multilib
--disable-bootstrap --disable-werror
Thread model: posix
gcc version 7.0.0 20160422 (experimental) (GCC)
[jamrial@ArchVM ~]$ time c++-7 -ftemplate-backtrace-limit=0 -Wall -Wextra
-pedantic -Werror -pedantic-errors -Wno-error=deprecated-declarations
-Wno-missing-field-initializers -Wno-unused-parameter -march=haswell -Ofast -g0
-std=gnu++14 -o transform_gcc5.o -c transform_gcc5.ii
real 1m57.807s
user 1m56.673s
sys 0m1.057s
[jamrial@ArchVM ~]$ time c++-7 -ftemplate-backtrace-limit=0 -Wall -Wextra
-pedantic -Werror -pedantic-errors -Wno-error=deprecated-declarations
-Wno-missing-field-initializers -Wno-unused-parameter -march=haswell -Ofast -g0
-std=gnu++14 -o transform_gcc6.o -c transform_gcc6.ii
real 2m20.146s
user 2m19.220s
sys 0m0.817s
[jamrial@ArchVM ~]$ time c++-7 -ftemplate-backtrace-limit=0 -Wall -Wextra
-pedantic -Werror -pedantic-errors -Wno-error=deprecated-declarations
-Wno-missing-field-initializers -Wno-unused-parameter -march=haswell -Ofast -g0
-std=gnu++14 -o transform_gcc7.o -c transform_gcc7.ii
real 2m22.689s
user 2m21.773s
sys 0m0.860s
GCC 5.3 performed the best for all three preprocessed files.
GCC 6.0.1 performed about the same as GCC 5.3 using the gcc5 preprocessed file.
It however trashed my HDD a lot trying to compile the preprocessed output from
both GCC 6 and GCC 7, and took longer to finish them. This may hint at
increased RAM usage and explain the odd time values, but i didn't check.
GCC 7 performed the worst across the table, even with the gcc5 preprocessed
file.
