https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61930
--- Comment #1 from Oleg Endo <olegendo at gcc dot gnu.org> --- I think this is related to PR 29969. In some cases it might make sense to do mem copy like insns either in SImode (if displacement addressing is better) or in SFmode (to reduce GP reg pressure). This is not only limited to constants, but can be applied to all load-store pairs of 4 or 8 bytes. Whether using FP regs or GP regs for a copy depends on the register pressure and the address modes that are required. If GP reg pressure is high and copy insns are blindly changed to use FP regs it might result in worse code because of additional address reg calculation insns added. I guess this type of optimization could be part of AMS.