Remove OpPPC64LoweredMuluhilo as this operation can be done
more efficiently with MULHDU and MULLD directly. This has the
benefit of not needing to use tuple select operations, and giving
the scheduler more freedom to place these operations.
The primary reason to avoid using tuples here is to to avoid
suboptimal scheduling when carry ops (e.x ADDC/ADDE) are used in
the same block as 64->128b multiples. CL 432275 modifies the
scheduling priorities which may cause non-flag/non-carry generating
tuple ops to interfere with carry opcodes. Thus resulting in excess
saving and restoring of the XER register.
This allows CL 432275 to adjust the scheduling priorities without
having to workaround odd tuple scheduling behavior.
Change-Id: Id04ef009ec4b86416e5436f2b44ae1474e73720e
Reviewed-on: https://go-review.googlesource.com/c/go/+/434855
Run-TryBot: Paul Murphy <murp@ibm.com> Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Keith Randall <khr@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com>