On Thu, Feb 02, 2017 at 08:51:19AM +0100, Jakub Jelinek wrote: > Thanks, though at this point I think the > http://gcc.gnu.org/ml/gcc-patches/2017-01/msg02390.html > patch is better. With the earliest patch (the one below) for -mvsx > -mno-popcntd (or whatever -mcpu= implies that) there is no DF->DI conversion > at all, while with the latest one (msg02390.html) we can still emit the > xscvdpuxds instruction (as the only alternative, kind like as if the > *fixuns_trunc<mode>di2_fctiduz instruction disabled the fctiduz alternative > if power7 isn't availkable, at least for DF->DI).
Both VSX and the fctiduz instruction were introduced with Power7. The -mpopcntd flag means "Use ISA 2.06 instructions" (that is, Power7 and later); the flag should really not exist at all but we are kind of stuck with it now. I think the patch will work, but I'd rather not make things more complex for no good, certainly not during stage 4. Thanks, Segher
