cmd/compile: intrinsify Sub64 on loong64
This is a follow up of CL 420095 on loong64.
file before after Δ %
compile/internal/ssa.a
35649482 35653274 +3792 +0.011%
compile/internal/ssagen.a
4099858 4098728 -1130 -0.028%
ecdh.a 227896 226896 -1000 -0.439%
internal/nistec/fiat.a
1212254 1128184 -84070 -6.935%
tls.a
3256800 3256802 +2 +0.000%
big.a
1708518 1702496 -6022 -0.352%
bits.a 106762 105734 -1028 -0.963%
math.a 578762 577288 -1474 -0.255%
netip.a 555922 555610 -312 -0.056%
net.a
3286528 3286530 +2 +0.000%
golang.org/x/crypto/internal/poly1305.a 109546 107686 -1860 -1.698%
total
260392768 260299668 -93100 -0.036%
Change-Id: Ieffca705aae5666501f284502d986ca179dde494
Reviewed-on: https://go-review.googlesource.com/c/go/+/428557
Reviewed-by: Carlos Amedee <carlos@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Wayne Zuo <wdvxdr@golangcn.org>