cmd/compile/internal/ssa: use BEQ/BNE to optimize the combination of XOR and EQ/NE on loong64
Reduce the number of go toolchain instructions on loong64 as follows:
file before after Δ %
go
1599056 1590560 -8496 -0.5313%
gofmt 326188 326104 -84 -0.0258%
asm 563482 561250 -2232 -0.3961%
cgo 488644 485252 -3392 -0.6942%
compile
2504614 2486388 -18226 -0.7277%
cover 526322 523270 -3052 -0.5799%
link 714532 711124 -3408 -0.4770%
preprofile 242316 241112 -1204 -0.4969%
vet 794446 786118 -8328 -1.0483%
Change-Id: I0914889119a28ea672b694529ef54513fbb3f3b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/693875
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: abner chenc <chenguoqi@loongson.cn>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Keith Randall <khr@google.com>