https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70847
Franz Sirl <sirl at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |sirl at gcc dot gnu.org --- Comment #6 from Franz Sirl <sirl at gcc dot gnu.org> --- Created attachment 38612 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38612&action=edit Testcase for -fsanitize=alignment For this testcase compiled with -fsanitize=alignment/-fsanitize=undefined the patch from comment#3 only shaves off about 4 seconds. The compiletime still roughly doubles with each string added to the operator<< chain. 1) time g++-6 -fsanitize=alignment tc3.cpp -c -ftime-report Execution times (seconds) phase setup : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 1575 kB (54%) ggc phase parsing : 143.08 (100%) usr 0.00 ( 0%) sys 143.09 (100%) wall 756 kB (26%) ggc phase opt and generate : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 597 kB (20%) ggc register information : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 0 kB ( 0%) ggc parser function body : 143.08 (100%) usr 0.00 ( 0%) sys 143.09 (100%) wall 151 kB ( 5%) ggc integrated RA : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 49 kB ( 2%) ggc initialize rtl : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 12 kB ( 0%) ggc TOTAL : 143.10 0.00 143.12 2939 kB real 2m23.132s user 2m23.108s sys 0m0.008s 2) g++-6 -v Using built-in specs. COLLECT_GCC=g++-6 COLLECT_LTO_WRAPPER=/usr/lib64/gcc/x86_64-suse-linux/6/lto-wrapper Target: x86_64-suse-linux Configured with: ../configure --prefix=/usr --infodir=/usr/share/info --mandir=/usr/share/man --libdir=/usr/lib64 --libexecdir=/usr/lib64 --enable-languages=c,c++,objc,fortran,obj-c++,java,ada,go --enable-checking=release --with-gxx-include-dir=/usr/include/c++/6 --enable-ssp --disable-libssp --disable-libvtv --disable-plugin --with-bugurl=http://bugs.opensuse.org/ --with-pkgversion='SUSE Linux' --disable-libgcj --with-slibdir=/lib64 --with-system-zlib --enable-__cxa_atexit --enable-libstdcxx-allocator=new --disable-libstdcxx-pch --with-default-libstdcxx-abi=gcc4-compatible --enable-version-specific-runtime-libs --enable-linker-build-id --enable-linux-futex --program-suffix=-6 --without-system-libunwind --enable-multilib --with-arch-32=x86-64 --with-tune=generic --build=x86_64-suse-linux --host=x86_64-suse-linux Thread model: posix gcc version 6.1.1 20160531 (SUSE Linux)