[Bug bootstrap/52041] [4.7 Regression] Bootstrap failure at revision 183650 with --enable-checking=release

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52041

--- Comment #6 from Dominique d'Humieres <dominiq at lps dot ens.fr> 2012-01-30 14:16:37 UTC ---
> I just bootstrapped r183695 (incl. Ada and Obj-C++) with
> --enable-checking=release  on i686-darwin9, using gcc4.6 as the bootstrap
> compiler.  What bootstrap compiler where you using?

[macbook] gcc/p_build% gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/opt/gcc/gcc4.7a/libexec/gcc/x86_64-apple-darwin10.8.0/4.7.0/lto-wrapper
Target: x86_64-apple-darwin10.8.0
Configured with: ../_clean/configure --prefix=/opt/gcc/gcc4.7a
--enable-languages=c,c++,fortran,ada,lto --with-gmp=/opt/mp --with-system-zlib
--enable-checking=release --with-cloog=/opt/mp --enable-cloog-backend=isl
--enable-lto
Thread model: posix
gcc version 4.7.0 20120117 (experimental) [trunk revision 183234] (GCC) 

Note that a clean bootstrap succeeded for revisions (above 183000) 183001,
183306, 183526 (patched), 183618, 183649, **183707**, and **183719**, but not
for revisions 183650 and 183669.
So it seems that bootstrap is back again due to some change between revision
183669 and 183695 (mostly gfortran, testsuite, ada, ... , but for r183684).

> I can reproduce random comparison failures as well, even with checking enabled,
> on openSUSE Factory x86_64.  I wasn't yet able to reproduce them locally
> though.
> I'm trying again.

Richard, what are "random comparison failures" (from PR51974)? Do the above
qualify?