cmd/internal/obj/loong64: optimize instruction implementation

The plan9 instructions ASLLV and -ASLLV are translated into the same assembly
instructions, so -ASLLV can be removed and replaced with ASLLV in the
corresponding position.

ASRLV and -ASRLV have the same reason as the above two instructions.

Change-Id: I4bd79ca7bb070f7a924a0205ef2f19cf2b9ae2c9
Reviewed-on: https://go-review.googlesource.com/c/go/+/565623
Reviewed-by: abner chenc <chenguoqi@loongson.cn>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: abner chenc <chenguoqi@loongson.cn>
Reviewed-by: Qiqi Huang <huangqiqi@loongson.cn>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: sophie zhao <zhaoxiaolin@loongson.cn>

diff --git a/src/cmd/internal/obj/loong64/asm.go b/src/cmd/internal/obj/loong64/asm.go
index fe71b90e8815e13121d5dc4bee9a6c03ee405a08..ee4a8bb8cb0b8a00aaa06c2634ebf89f50dfcada 100644 (file)
--- a/src/cmd/internal/obj/loong64/asm.go
+++ b/src/cmd/internal/obj/loong64/asm.go
@@ -1453,8 +1453,8 @@ func (c *ctxt0) asmout(p *obj.Prog, o *Optab, out []uint32) {
        case 14: // movwu r,r
                // NOTE: this case does not use REGTMP. If it ever does,
                // remove the NOTUSETMP flag in optab.
-               o1 = OP_16IRR(c.opirr(-ASLLV), uint32(32)&0x3f, uint32(p.From.Reg), uint32(p.To.Reg))
-               o2 = OP_16IRR(c.opirr(-ASRLV), uint32(32)&0x3f, uint32(p.To.Reg), uint32(p.To.Reg))
+               o1 = OP_16IRR(c.opirr(ASLLV), uint32(32)&0x3f, uint32(p.From.Reg), uint32(p.To.Reg))
+               o2 = OP_16IRR(c.opirr(ASRLV), uint32(32)&0x3f, uint32(p.To.Reg), uint32(p.To.Reg))
 
        case 15: // teq $c r,r
                v := c.regoff(&p.From)
@@ -2169,17 +2169,13 @@ func (c *ctxt0) opirr(a obj.As) uint32 {
        case -AMOVD:
                return 0x0ae << 22
 
-       case ASLLV,
-               -ASLLV:
+       case ASLLV:
                return 0x0041 << 16
-       case ASRLV,
-               -ASRLV:
+       case ASRLV:
                return 0x0045 << 16
-       case ASRAV,
-               -ASRAV:
+       case ASRAV:
                return 0x0049 << 16
-       case AROTRV,
-               -AROTRV:
+       case AROTRV:
                return 0x004d << 16
        case -ALL:
                return 0x020 << 24