cmd/compile/internal/ssa: eliminate unnecessary extension operations
Reduce the number of go toolchain instructions on loong64 as follows:
file before after Δ %
go
1598706 1597230 -1476 -0.0923%
gofmt 325180 324736 -444 -0.1365%
asm 562538 562098 -440 -0.0782%
cgo 488298 487634 -664 -0.1360%
compile
2504502 2503590 -912 -0.0364%
cover 525976 525312 -664 -0.1262%
link 714182 713226 -956 -0.1339%
preprofile 241308 240988 -320 -0.1326%
vet 794112 793316 -796 -0.1002%
Change-Id: I048ef79518b41e83c53da1a3a6b7edaca7cb63f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/693856
Reviewed-by: abner chenc <chenguoqi@loongson.cn>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: sophie zhao <zhaoxiaolin@loongson.cn>