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| author | Gregory P. Smith ext:(%20%5BGoogle%20Inc.%5D) <greg@krypto.org> | 2016-06-02 23:44:40 +0000 |
|---|---|---|
| committer | Gregory P. Smith ext:(%20%5BGoogle%20Inc.%5D) <greg@krypto.org> | 2016-06-02 23:44:40 +0000 |
| commit | c543a0fc3b2052c35fced09e1f96613625723508 (patch) | |
| tree | f551ebf654a813212517ab06f94ca3908e67d5ea /configure.ac | |
| parent | e725777eaf430c67db5f4c9cc1f5ee77bc5ad3b5 (diff) | |
| download | cpython-git-c543a0fc3b2052c35fced09e1f96613625723508.tar.gz | |
Issue #25702: A --with-lto configure option has been added that will
enable link time optimizations at build time during a make profile-opt.
Some compilers and toolchains are known to not produce stable code when
using LTO, be sure to test things thoroughly before relying on it.
It can provide a few % speed up over profile-opt alone.
Diffstat (limited to 'configure.ac')
| -rw-r--r-- | configure.ac | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/configure.ac b/configure.ac index f0082fdfb6..06c877b854 100644 --- a/configure.ac +++ b/configure.ac @@ -1377,6 +1377,40 @@ then fi +# Enable LTO flags +AC_SUBST(LTOFLAGS) +AC_MSG_CHECKING(for --with-lto) +AC_ARG_WITH(lto, AS_HELP_STRING([--with-lto], [Enable Link Time Optimization in PGO builds. Disabled by default.]), +[ +if test "$withval" != no +then + Py_LTO='true' + AC_MSG_RESULT(yes); +else + Py_LTO='false' + AC_MSG_RESULT(no); +fi], +[AC_MSG_RESULT(no)]) +if test "$Py_LTO" = 'true' ; then + case $CC in + *clang*) + # Any changes made here should be reflected in the GCC+Darwin case below + LTOFLAGS="-flto" + ;; + *gcc*) + case $ac_sys_system in + Darwin*) + LTOFLAGS="-flto" + ;; + *) + LTOFLAGS="-flto -fuse-linker-plugin -ffat-lto-objects -flto-partition=none" + ;; + esac + ;; + esac +fi + + # Enable PGO flags. AC_SUBST(PGO_PROF_GEN_FLAG) AC_SUBST(PGO_PROF_USE_FLAG) |