cmd/compile: make isUint{32,64}PowerOfTwo implementations clearer
Since these functions cast the input to uint64, so the result always
non-negative. The condition should be changed to comparing with zero,
thus maaking it clearer to reader, and open room for simplifying in the
future by using the generic isUnsignedPowerOfTwo function.
Separated this change, so it's easier to do bisecting if there's any
problems happened.
Change-Id: Ibec28c2590f4c52caa36384b710d526459725e49
Reviewed-on: https://go-review.googlesource.com/c/go/+/692915 Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com> Reviewed-by: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Keith Randall <khr@google.com>