[PATCH] middle-end: Skip initialization of opaque type register variables [PR103127]
Tue Nov 30 22:35:10 GMT 2021
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.
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