cmd/compile/internal/ssa: reintroduce ANDconst opcode on PPC64
This allows more effective conversion of rotate and mask opcodes
into their CC equivalents, while simplifying the first lowering
pass.
This was removed before the latelower pass was introduced to fold
more cases of compare against zero. Add ANDconst to push the
conversion of ANDconst to ANDCCconst into latelower with the other
CC opcodes.
This also requires introducing RLDICLCC to prevent regressions
when ANDconst is converted to RLDICL then to RLDICLCC and back
to ANDCCconst when possible.
Change-Id: I9e5f9c99fbefa334db18c6c152c5f967f3ff2590
Reviewed-on: https://go-review.googlesource.com/c/go/+/586160 Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Carlos Amedee <carlos@golang.org>