cmd/compile: report more non-inlineable functions

Many non-inlineable functions were not being
reported in '-m -m' mode.

Updates #17858.

Change-Id: I7d96361b39dd317f5550e57334a8a6dd1a836598
Reviewed-on: https://go-review.googlesource.com/32971
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

src/cmd/compile/internal/gc/inl.go

@@ -268,7 +268,12 @@ func ishairy(n *Node, budget *int32, reason *string) bool {
 		*budget -= 2
 	}
 
-	return *budget < 0 || ishairy(n.Left, budget, reason) || ishairy(n.Right, budget, reason) ||
+	if *budget < 0 {
+		*reason = "function too complex"
+		return true
+	}
+
+	return ishairy(n.Left, budget, reason) || ishairy(n.Right, budget, reason) ||
 		ishairylist(n.List, budget, reason) || ishairylist(n.Rlist, budget, reason) ||
 		ishairylist(n.Ninit, budget, reason) || ishairylist(n.Nbody, budget, reason)
 }