If current mainline is used to compile GMP 4.2 on a Pentium4 with a standard ./configure; make; make check one of GMP's checks fails:
[...] make[4]: Entering directory `/scratch/gmp-4.2/tests/mpz' PASS: t-addsub PASS: t-cmp ERROR: incorrect plain product in test 53 op1 = -FFFFFFFFFFFFFFFFFFFFFFFFF...0000000000000000000000000 [71992] op2 = 1FFFFFFFFFFFFFFFFFFFFFFFF...FFFFFFFFFFFFFFFFFFFFFFFFF [202386] product = -61EDD19F23160438880BD99C5...-6701F030DAFAEAD82176BAB51 [274384] ref_product = -1FFFFFFFFFFFFFFFFFFFFFFFF...0000000000000000000000000 [274378] FAIL: t-mul PASS: t-mul_i PASS: t-tdiv [...] Of course this may be a bug in GMP itself, but I could not reproduce this failure with gcc 4.1 or the head of the 4.1 branch -- Summary: Problem when compiling GMP 4.2 with current mainline Product: gcc Version: 4.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: other AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: martin at mpa-garching dot mpg dot de GCC build triplet: i686-pc-linux-gnu GCC host triplet: i686-pc-linux-gnu GCC target triplet: i686-pc-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27322