cmd/compile: cleanup code in getInstInfo to use switch statement
Simple cleanup: convert a bunch of if's to a switch statement in
getInstInfo. Also, use a few extra variables to avoid repeated node
conversions (such as n.(*ir.CallExpr))
Change-Id: I7a2a4efb569415256a8bc9350fb100bd2d8cfb39
Reviewed-on: https://go-review.googlesource.com/c/go/+/356311
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
Trust: Dan Scales <danscales@google.com>