cmd/compile: preserve shift boundness during wasm rewrite rules
Mostly for clarity. There are nominal improvements to the generated code:
file before after Δ %
addr2line
4742769 4742639 -130 -0.003%
api
6973284 6973209 -75 -0.001%
asm
5922230 5922127 -103 -0.002%
buildid
3117327 3117252 -75 -0.002%
cgo
5539274 5539199 -75 -0.001%
compile
27423605 27424940 +1335 +0.005%
cover
6096973 6096898 -75 -0.001%
dist
4121655 4121580 -75 -0.002%
doc
5386254 5386179 -75 -0.001%
fix
3755243 3755168 -75 -0.002%
link
7602682 7602607 -75 -0.001%
nm
4687186 4687056 -130 -0.003%
objdump
5184883 5184753 -130 -0.003%
pack
2511360 2511285 -75 -0.003%
pprof
16872050 16871832 -218 -0.001%
test2json
3060633 3060558 -75 -0.002%
trace
13170181 13170018 -163 -0.001%
vet
9865995 9865920 -75 -0.001%
total
151188868 151188504 -364 -0.000%
Change-Id: If765e3661549d183a2dbb44e83521c4a3f61d175
Reviewed-on: https://go-review.googlesource.com/c/go/+/216998
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>