https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85854
Bug ID: 85854
Summary: Performance regression from gcc 4.9.2
Product: gcc
Version: 8.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: beldmit at gmail dot com
Target Milestone: ---
Created attachment 44154
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44154&action=edit
Preprocessing file.
I got a serious (10%) performance degradation using cross-compiler for ARM.
Compiler version:
arm-linux-gnueabihf-gcc-8 -v
Using built-in specs.
COLLECT_GCC=arm-linux-gnueabihf-gcc-8
COLLECT_LTO_WRAPPER=/usr/lib/gcc-cross/arm-linux-gnueabihf/8/lto-wrapper
Target: arm-linux-gnueabihf
Configured with: ../src/configure -v --with-pkgversion='Debian 8.1.0-3'
--with-bugurl=file:///usr/share/doc/gcc-8/README.Bugs
--enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++ --prefix=/usr
--with-gcc-major-version-only --program-suffix=-8 --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-libitm
--disable-libquadmath --disable-libquadmath-support --enable-plugin
--enable-default-pie --with-system-zlib --with-target-system-zlib
--enable-multiarch --disable-sjlj-exceptions --with-arch=armv7-a
--with-fpu=vfpv3-d16 --with-float=hard --with-mode=thumb --disable-werror
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=arm-linux-gnueabihf --program-prefix=arm-linux-gnueabihf-
--includedir=/usr/arm-linux-gnueabihf/include
Thread model: posix
gcc version 8.1.0 (Debian 8.1.0-3)
System: Linux x-debian 4.16.0-1-amd64 #1 SMP Debian 4.16.5-1 (2018-04-29)
x86_64 GNU/Linux
Compiler options:
arm-linux-gnueabihf-gcc-8 -c -DSTRICT_OFFSET -mfpu=neon -O1 -D_REENTRANT
-DTHREAD_TYPE=THREAD_TYPE_PTHREADS -fPIC -DNDEBUG -DCC_NO_RDS_SOCKET
-DCC_NO_RDS_FILECNT -DCC_NO_RDS_NP -D_GNU_SOURCE -pedantic -Wall -Wextra
-Wno-long-long -g -save-temps gosthash2012.c
The preprocessed file is attached. The most time-taking part of the code is the
function named g.
The new version does not use neon vector ops (such as veor) at all, but the
4.9.2 on native ARM system does.
The system withoud degradation is
Linux odroid 3.10.107 #1 SMP PREEMPT Wed Sep 13 18:48:10 CEST 2017 armv7l
GNU/Linux
gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/arm-linux-gnueabihf/4.9/lto-wrapper
Target: arm-linux-gnueabihf
Configured with: ../src/configure -v --with-pkgversion='Debian 4.9.2-10'
--with-bugurl=file:///usr/share/doc/gcc-4.9/README.Bugs
--enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.9 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.9 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --enable-gnu-unique-object --disable-libitm
--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-4.9-armhf/jre --enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.9-armhf
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.9-armhf
--with-arch-directory=arm --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--enable-objc-gc --enable-multiarch --disable-sjlj-exceptions
--with-arch=armv7-a --with-fpu=vfpv3-d16 --with-float=hard --with-mode=thumb
--enable-checking=release --build=arm-linux-gnueabihf
--host=arm-linux-gnueabihf --target=arm-linux-gnueabihf
Thread model: posix
gcc version 4.9.2 (Debian 4.9.2-10)
