Jim Meyering <j...@meyering.net> writes: > Eric Blake wrote: >> On 12/03/2011 09:00 AM, Simon Josefsson wrote: >>> What does -funit-at-a-time really do? My gcc 4.4 manual says: >>> >>> `-funit-at-a-time' >>> This option is left for compatibility reasons. `-funit-at-a-time' >>> has no effect, while `-fno-unit-at-a-time' implies >>> `-fno-toplevel-reorder' and `-fno-section-anchors'. >>> >>> Enabled by default. >> >> That's the case for 4.4 and later. But in gcc 4.3, it was not >> unconditionally enabled, and as I said earlier, at least coreutils ran >> into a situation where gcc 4.3. failed to compile at -Werror because >> -Wdisabled-optimization warned that -fno-unit-at-a-time was required, >> which warning turned into an error. >> >> At this point, gcc 4.3 is slowly phasing out; most Linux distros and >> Cygwin have moved on to newer compilers, where the problem is less >> likely to happen. > > IMHO, we should treat --enable-gcc-warnings as something that must work > well with the latest stable version of gcc (currently 4.6) and recent > glibc headers. Trying to accommodate older versions of gcc does not seem > worthwhile. Just tell people who use old versions of gcc not to use > --enable-gcc-warnings, or even detect that and turn it off automatically.
I think this is a good approach: I wouldn't want workarounds for issues in old gcc in manywarnings.m4. Manywarnings is a maintainer tool, and maintainers can be required to have newer tools than users, so manywarnings could require more recent tools. However, personally I still use gcc 4.4 on my primary development machine, so if it isn't difficult to support it, I'd prefer that. /Simon
