cmd/compile: tweak inlining to favor PPARAM call sites
If a function f being considered for inlining calls
one of its parameters, reduce the normal cost of that
call (57) to 17 to increase the chance that f will
be inlined and (with luck) that parameter will be
revealed as a constant function (which unblocks
escape analysis) or perhaps even be inlined.
The least-change value for that was still effective for
iter_test benchmarks was 32; however tests showed no
particular harm even when reduced as low as 7, and there
have been reports of other performance problems with
rangefunc overheads and so I picked a middling number
in hopes of warding off such reports.
Updates #69015
Change-Id: I2a525c1beffb9f88daa14caa8a622864b023675c
Reviewed-on: https://go-review.googlesource.com/c/go/+/609095
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Keith Randall <khr@google.com> Reviewed-by: Tim King <taking@google.com> Reviewed-by: Keith Randall <khr@golang.org>