Kyrill Tkachov wrote: > > After Bernd's change almost all DI mode instructions are split before > > register > > allocation. So instructions using DI mode no longer exist and thus these > > extend variants can never be matched and are thus redundant. > > Bernd's patch splits them when we don't have NEON. When NEON is > available though > they still maintain the DImode so we'd still benefit from these > transformations, no?
While you're right it may be possible to trigger these instructions, ORN is already so rare that it is hardly beneficial to have an instruction for it, and ORN of an extended value never ever happens. So there is absolutely no benefit in keeping these versions temporarily until we fix Neon too. For the Neon case my proposal is to use the VFP early expansion (so you get an efficient expansion by default in all cases). You can then use -mneon-for-64bits to enable the use of Neon instructions (which may be even better in some cases). There are quite a few patches in this series already and more to come soon! Wilco