cmd/compile/internal/inline: minor compile time improvements in func flags
Some small changes to help reduce compile time for function flags
computation. The current implementation of panic path detection adds
an entry to a map for every node in the function, which is wasteful
(and shows up in cpu profiles). Switch to only adding entries where
they are useful. This is especially important for functions with large
map literals and other constructs with many non-statement nodes.
Change-Id: I9cfb2cd1cbf480f21298e6102aa99e2d77219f3d
Reviewed-on: https://go-review.googlesource.com/c/go/+/539696 Reviewed-by: Matthew Dempsky <mdempsky@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>