http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59025
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> --- If I remember well, there was one spot where it could result in swapped order of commutative operation's operand at the tree level, plus of course if RA/scheduling is affected by SSA_NAME_VERSION of the temporaries (or, because the new SSA_NAMEs intentionally are anonymous, while previously they could still be from some original vars with underlying decls on them, it could result in slightly different SSA partitioning). But none of that sounds like a compiler bug, perhaps just 435.gromacs worked with -ffast-math on ppc previously just by accident, perhaps the test isn't prepared to handle reordering of floating point operations allowed by -ffast-math?
