Re: [PATCH 00/18] resurrect automatic dependency tracking

["Joseph S. Myers" <joseph at codesourcery dot com>]

On Thu, 25 Jul 2013, Tom Tromey wrote:

> That patch was ultimately reverted due to a GNU make bug.  This time
> around, thanks to git, I chose to make a patch series.  This way, even
> if we stumble across the bug again (it is not clear it was ever
> fixed), we can determine which patch triggers it, and still possibly
> gain some benefit from the remaining patches.

We have a reliable reproducer for the bug, at least in the form in which 
it appeared with the old patch: 
<http://gcc.gnu.org/ml/gcc-patches/2008-03/msg01663.html> - even though 
it was never clear exactly what the make bug was (the one referred to in 
that discussion appeared to rely on makefile features that weren't used by 
the old GCC patch).

Thus, it would seem appropriate, for each of the 18 successive states 
after an initial subsequence of the patches is applied, to verify that, if 
you build with make 3.81, touch Makefile.in and then do make -j2 cc1, it 
does not produce the hang previously observed.  (Or just verify this for 
the state after all 18 are applied; no need to try intermediate states 
without evidence that the series as a whole has problems with the make 
bug.)

-- 
Joseph S. Myers
joseph@codesourcery.com