On 11/30/21 2:44 PM, Qing Zhao via Gcc-patches wrote: > Sorry for the confusing… > My major question is: > > for a variable of type __vector_pair, could it be in a register?
Yes. To be pedantic, it will live in a vector register pair. > If it could be in a register, can we initialize this register with some > constant value? For a __vector_pair, no, not as it is setup now. We also do not have a use case where we would want to initialize a __vector_pair to a constant. Our normal (only?) use case with a __vector_pair is to load it up with some actual data from memory that represents a (partial) row of a matrix. For __vector_quad, it too lives in a register (accumulator register) and represents a small matrix. We have the __builtin_mma_xxsetaccz (&acc) builtin to initialize it to a zero constant. Peter
