cmd/compile: compute Modu's maximum limits from argument's limits
addLocalFacts loop already ft.update which sets up limits correctly, but doing this in flowLimit help us since other values might depend on this limit.
Updates #68857
We could improve this further:
- remove mod alltogheter when we can prove a < b.
- we could do more adhoc computation in flowLimit to set umax and umin tighter
Change-Id: I5184913577b6a51a07cb53a6e6b73552a982de0b
Reviewed-on: https://go-review.googlesource.com/c/go/+/605156 Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>