// SC	Rtmp, (Rarg0)
		// BEQ	Rtmp, -3(PC)
		// DBAR
		{name: "LoweredAtomicExchange32", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true, unsafePoint: true},
		{name: "LoweredAtomicExchange64", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true, unsafePoint: true},

		// atomic add.
		// *arg0 += arg1. arg2=mem. returns <new content of *arg0, memory>.
		// DBAR

		// SC	Rtmp, (Rarg0)
		// BEQ	Rtmp, -3(PC)
		// SYNC
		{name: "LoweredAtomicExchange32", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true, unsafePoint: true},
		{name: "LoweredAtomicExchange64", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true, unsafePoint: true},

		// atomic add.
		// *arg0 += arg1. arg2=mem. returns <new content of *arg0, memory>.
		// SYNC

		// store arg1 to *arg0. arg2=mem. returns <old content of *arg0, memory>.
		{name: "LoweredAtomicExchange32", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},
		{name: "LoweredAtomicExchange64", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true},

		// Atomic add.
		// *arg0 += arg1. arg2=mem. returns <new content of *arg0, memory>.

		// BNE          -2(PC)
		// ISYNC
		// return old val
		{name: "LoweredAtomicExchange32", argLength: 3, reg: gpxchg, resultNotInArgs: true, clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true},
		{name: "LoweredAtomicExchange64", argLength: 3, reg: gpxchg, resultNotInArgs: true, clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true},

		// atomic compare and swap.

		{name: "LoweredAtomicExchange32", argLength: 3, reg: exchange, asm: "CS", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true, symEffect: "RdWr"},
		{name: "LoweredAtomicExchange64", argLength: 3, reg: exchange, asm: "CSG", aux: "SymOff", clobberFlags: true, faultOnNilArg0: true, hasSideEffects: true, symEffect: "RdWr"},

		// find leftmost one
		{
			name:         "FLOGR",

		// atomic exchange.
		// store arg1 to arg0. arg2=mem. returns <old content of *arg0, memory>. auxint must be zero.
		// LDAXR	(Rarg0), Rout
		// STLXR	Rarg1, (Rarg0), Rtmp
		// CBNZ		Rtmp, -2(PC)
		{name: "LoweredAtomicExchange64", argLength: 3, reg: gpxchg, resultNotInArgs: true, faultOnNilArg0: true, hasSideEffects: true, unsafePoint: true},

(Select1     (AddTupleFirst64   _ tuple)) => (Select1 tuple)

// Atomic exchanges.
(AtomicExchange32 ptr val mem) => (LoweredAtomicExchange32 ptr val mem)
(AtomicExchange64 ptr val mem) => (LoweredAtomicExchange64 ptr val mem)

// Atomic compare and swap.
(AtomicCompareAndSwap32 ptr old new_ mem) => (LoweredAtomicCas32 ptr old new_ mem)
(AtomicCompareAndSwap64 ptr old new_ mem) => (LoweredAtomicCas64 ptr old new_ mem)

				{0, 9223372038733561855}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 g R30 SP SB
			},
		},
	},
	{
		name:            "LoweredAtomicExchange64",
		argLen:          3,
		resultNotInArgs: true,
		faultOnNilArg0:  true,
		hasSideEffects:  true,
		unsafePoint:     true,
		reg: regInfo{
			inputs: []inputInfo{

		return true
	}
}
func rewriteValueS390X_OpAtomicExchange64(v *Value) bool {
	v_2 := v.Args[2]
	v_1 := v.Args[1]
	v_0 := v.Args[0]
	// match: (AtomicExchange64 ptr val mem)
	// result: (LoweredAtomicExchange64 ptr val mem)
	for {
		ptr := v_0
		val := v_1
		mem := v_2
		v.reset(OpS390XLoweredAtomicExchange64)
		v.AddArg3(ptr, val, mem)
		return true
	}
}