From d37a1bdd48458e48de13cdc320c8ddf9b021e356 Mon Sep 17 00:00:00 2001
From: Xiaolin Zhao <zhaoxiaolin@loongson.cn>
Date: Mon, 19 May 2025 17:02:48 +0800
Subject: [PATCH] cmd/compile: fix the implementation of NORconst on loong64

In the loong64 instruction set, there is no NORI instruction,
so the immediate value in NORconst need to be stored in register
and then use the three-register NOR instruction.

Change-Id: I5ef697450619317218cb3ef47fc07e238bdc2139
Reviewed-on: https://go-review.googlesource.com/c/go/+/673836
Reviewed-by: abner chenc <chenguoqi@loongson.cn>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
---
 src/cmd/compile/internal/loong64/ssa.go | 18 +++++++++++++++++-
 test/codegen/bits.go                    |  9 +++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/cmd/compile/internal/loong64/ssa.go b/src/cmd/compile/internal/loong64/ssa.go
index d60aef165c..03d7a1082a 100644
--- a/src/cmd/compile/internal/loong64/ssa.go
+++ b/src/cmd/compile/internal/loong64/ssa.go
@@ -276,7 +276,6 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		ssa.OpLOONG64ANDconst,
 		ssa.OpLOONG64ORconst,
 		ssa.OpLOONG64XORconst,
-		ssa.OpLOONG64NORconst,
 		ssa.OpLOONG64SLLconst,
 		ssa.OpLOONG64SLLVconst,
 		ssa.OpLOONG64SRLconst,
@@ -293,6 +292,23 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		p.Reg = v.Args[0].Reg()
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = v.Reg()
+
+	case ssa.OpLOONG64NORconst:
+		// MOVV $const, Rtmp
+		// NOR  Rtmp, Rarg0, Rout
+		p := s.Prog(loong64.AMOVV)
+		p.From.Type = obj.TYPE_CONST
+		p.From.Offset = v.AuxInt
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = loong64.REGTMP
+
+		p2 := s.Prog(v.Op.Asm())
+		p2.From.Type = obj.TYPE_REG
+		p2.From.Reg = loong64.REGTMP
+		p2.Reg = v.Args[0].Reg()
+		p2.To.Type = obj.TYPE_REG
+		p2.To.Reg = v.Reg()
+
 	case ssa.OpLOONG64MOVVconst:
 		r := v.Reg()
 		p := s.Prog(v.Op.Asm())
diff --git a/test/codegen/bits.go b/test/codegen/bits.go
index c20e4d6733..95e0ed85e4 100644
--- a/test/codegen/bits.go
+++ b/test/codegen/bits.go
@@ -335,6 +335,15 @@ func op_orn(x, y uint32) uint32 {
 	return x | ^y
 }
 
+func op_nor(x int64, a []int64) {
+	// loong64: "MOVV\t[$]0","NOR\tR"
+	a[0] = ^(0x1234 | x)
+	// loong64:"NOR",-"XOR"
+	a[1] = (-1) ^ x
+	// loong64: "MOVV\t[$]-55",-"OR",-"NOR"
+	a[2] = ^(0x12 | 0x34)
+}
+
 // check bitsets
 func bitSetPowerOf2Test(x int) bool {
 	// amd64:"BTL\t[$]3"