https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123604
--- Comment #11 from Richard Earnshaw <rearnsha at gcc dot gnu.org> --- The formation of the adds instructions relies on being able to adjust the mode of the comparison used (so that we can express how the condition flags have to be tested in the subsequent conditional instructions. Combine can only do this if there is a single use of the condition register that can be adjusted. The change to CE can lead to multiple uses of the condition register (it can create multiple mov<mode>cc insns) and this is to complex for combine to handle. At this point it then has to abandon the attempt to fuse the arithmetic and compare pattern.
