hello all, I have been playing with the command-line options recently, and I'l appreciate answers, if someone has got time. ~ $ gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-unknown-linux-gnu/4.7.0/lto-wrapper Target: x86_64-unknown-linux-gnu Configured with: /build/src/gcc-4.7-20120505/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 --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-clocale=gnu --disable-libstdcxx-pch --enable-libstdcxx-time --enable-gnu-unique-object --enable-linker-build-id --with-ppl --enable-cloog-backend=isl --enable-lto --enable-gold --enable-ld=default --enable-plugin --with-plugin-ld=ld.gold --with-linker-hash-style=gnu --disable-multilib --disable-libssp --disable-build-with-cxx --disable-build-poststage1-with-cxx --enable-checking=release Thread model: posix gcc version 4.7.0 20120505 (prerelease) (GCC) ~ $ grep 'model name' /proc/cpuinfo model name : Intel(R) Core(TM) i3 CPU M 350 @ 2.27GHz first, is momit-leaf-frame-pointer bad for debugging (in the way fomit-frame-pointer can be)?, if not, why is it disabled by default even when optimizing (as -Q --help=target | grep omit reveals)? next, the manual mentions that fno-fat-lto-objects improves compilation time over plain LTO, but requires the whole toolchain to be aware of LTO and support plugins, which is why it's not (yet) the default. how can I know for certain if the toolchain I'm using meets the criteria (seems to be the case)? similarly, mtls-dialect=gnu2 is better then the default gnu, "but it may add compile- and run-time requirements that cannot be satisfied on all systems." how can I test for them? is it true that mfpmath=sse can result in poor code when using glibc? (maybe I shouldn't ask that here...) why is msse disabled by default even after march=native, while msse[234], msse4.[12] and mssse3 are all enabled? isn't the CRC32 instruction part of sse4.2?, why is mcrc32 disabled by default even when sse4.2 is enabled? thanks in advance, and sorry for bothering...
