diff options
| -rw-r--r-- | ChangeLog | 3 | ||||
| -rw-r--r-- | configure.ac | 5 |
2 files changed, 7 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog index 17d3f9401a3..07954be7d6b 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,8 @@ 2014-06-20 Paul Eggert <eggert@cs.ucla.edu> + * configure.ac: Warn about --enable-link-time-optimization's issues + in --help message (Bug#17806). + Port to GCC 4.9.0 with link time optimization (Bug#17806). * configure.ac (CFLAGS): With link time optimization, use -ffat-lto-objects if supported; otherwise Emacs won't diff --git a/configure.ac b/configure.ac index e9400047edc..3d840a1b484 100644 --- a/configure.ac +++ b/configure.ac @@ -757,7 +757,10 @@ AC_ARG_ENABLE([gcc-warnings], AC_ARG_ENABLE(link-time-optimization, [AS_HELP_STRING([--enable-link-time-optimization], [build emacs with link-time optimization. - This is supported only for GCC since 4.5.0.])], + This requires GCC 4.5.0 or later. + It also makes Emacs harder to debug, and when we tried it + with GCC 4.9.0 x86-64 it made Emacs slower, so it's not + recommended for typical use.])], if test "${enableval}" != "no"; then AC_MSG_CHECKING([whether link-time optimization is supported]) ac_lto_supported=no |