Consolidate all IR logic for getting the identity value of a reduction [nfc]

This change merges the three different places (at the IR layer) for
finding the identity value of a reduction into a single copy.  This
depends on several prior commits which fix ommissions and bugs in
the distinct copies, but this patch itself should be fully
non-functional.

As the new comments and naming try to make clear, the identity value
is a property of the @llvm.vector.reduce.* intrinsic, not of e.g.
the recurrence descriptor.  (We still provide an interface for
clients using recurrence descriptors, but the implementation simply
translates to the intrinsic which each corresponds to.)

As a note, the getIntrinsicIdentity API does not support fminnum/fmaxnum
or fminimum/fmaximum which is why we still need manual logic (but at
least only one copy of manual logic) for those cases.

0 files changed, 0 insertions, 0 deletions