https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78994
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|-Ofast makes aarch64 C++ |-Ofast makes aarch64 C++
|benchmark slower |benchmark slower for A53
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
For me on ThunderX, -Ofast is faster:
apinski@apinski-ss1:~/src/tests1$ g++ main.ii -Ofast -std=c++14 -mcpu=thunderx
apinski@apinski-ss1:~/src/tests1$ ./a.out
DSP Bench C++
Biquad coefficients:
b0=1.0045897513638202,
b1=-1.9900946111700766,
b2=0.98618704929508227,
a1=-1.9900946111700766,
a2=0.99077680065890239,
iir: 62008 ns per loop
iir_2: 62008 ns per loop
apinski@apinski-ss1:~/src/tests1$ g++ main.ii -O3 -std=c++14 -mcpu=thunderx
apinski@apinski-ss1:~/src/tests1$ ./a.out
DSP Bench C++
Biquad coefficients:
b0=1.0045897513638202,
b1=-1.9900946111700766,
b2=0.98618704929508227,
a1=-1.9900946111700766,
a2=0.99077680065890239,
iir: 80256 ns per loop
iir_2: 80256 ns per loop
apinski@apinski-ss1:~/src/tests1$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/aarch64-linux-gnu/5/lto-wrapper
Target: aarch64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
5.4.0-6ubuntu1~16.04.1' --with-bugurl=file:///usr/share/doc/gcc-5/README.Bugs
--enable-languages=c,ada,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-5 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-libquadmath --enable-plugin --with-system-zlib
--disable-browser-plugin --enable-java-awt=gtk --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.5.0-gcj-5-arm64/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-5-arm64
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-5-arm64
--with-arch-directory=aarch64 --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-multiarch --enable-fix-cortex-a53-843419 --disable-werror
--enable-checking=release --build=aarch64-linux-gnu --host=aarch64-linux-gnu
--target=aarch64-linux-gnu
Thread model: posix
gcc version 5.4.0 20160609 (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.1)
On the trunk:
apinski@apinski-ss1:~/src/tests1$ ~/src/local/tools/bin/g++ main.ii -O3
-std=c++14 -mcpu=thunderx
apinski@apinski-ss1:~/src/tests1$ ./a.out
DSP Bench C++
Biquad coefficients:
b0=1.0045897513638202,
b1=-1.9900946111700766,
b2=0.98618704929508227,
a1=-1.9900946111700766,
a2=0.99077680065890239,
iir: 80630 ns per loop
iir_2: 80629 ns per loop
apinski@apinski-ss1:~/src/tests1$ ~/src/local/tools/bin/g++ main.ii -Ofast
-std=c++14 -mcpu=thunderx
apinski@apinski-ss1:~/src/tests1$ ./a.out
DSP Bench C++
Biquad coefficients:
b0=1.0045897513638202,
b1=-1.9900946111700766,
b2=0.98618704929508227,
a1=-1.9900946111700766,
a2=0.99077680065890239,
iir: 62108 ns per loop
iir_2: 62118 ns per loop
apinski@apinski-ss1:~/src/tests1$ ~/src/local/tools/bin/g++ -v
Using built-in specs.
COLLECT_GCC=/home/apinski/src/local/tools/bin/g++
COLLECT_LTO_WRAPPER=/data/src/local/tools/bin/../libexec/gcc/aarch64-unknown-linux-gnu/7.0.0/lto-wrapper
Target: aarch64-unknown-linux-gnu
Configured with: ../gcc/configure
--prefix=/home/apinski/src/local/objdir/../tools
--enable-languages=c,c++,fortran,go --disable-werror --with-sysroot=/
--enable-plugins --enable-gnu-indirect-function --with-pkgversion='My build'
Thread model: posix
gcc version 7.0.0 20161110 (experimental) [trunk revision 242061] (My build)
