On Thu, Apr 16, 2020 at 12:45:46PM -0400, Michael Meissner wrote: > > > + /* Mask the element to make sure the element number is between 0 > > > and the > > > + maximum number of elements - 1 so that we don't generate an address > > > + outside the vector. */ > > > > Hrm, so why do you need to do this here? It is part of the semantics of > > vec_extract, so shouldn't the RTL already have this masking somewhere > > when we get here? > > Yes, as we discussed when it went into the master branch, the PowerPC > vec_extract built-in function explicitly requires the masking, rather than it > being undefined. Currently, the masking is not done when the built-in is > created, but only when it is split into the smaller insns.
That is very fragile. Can that not be fixed? > What makes this more complicated that normal is that while we have VEC_SELECT > for the case where the index is constant, VEC_SELECT does not work for a > variable index. But it could, RTL supports that just fine. Segher
