p.To.Reg = v.Reg()

	case ssa.Op386LoweredWB:
		p := s.Prog(obj.ACALL)
		p.To.Type = obj.TYPE_MEM
		p.To.Name = obj.NAME_EXTERN
		// AuxInt encodes how many buffer entries we need.
		p.To.Sym = ir.Syms.GCWriteBarrier[v.AuxInt-1]

	case ssa.Op386LoweredPanicBoundsA, ssa.Op386LoweredPanicBoundsB, ssa.Op386LoweredPanicBoundsC:
		p := s.Prog(obj.ACALL)
		p.To.Type = obj.TYPE_MEM
		p.To.Name = obj.NAME_EXTERN

		s.TailCall(v)
	case ssa.OpS390XLoweredWB:
		p := s.Prog(obj.ACALL)
		p.To.Type = obj.TYPE_MEM
		p.To.Name = obj.NAME_EXTERN
		// AuxInt encodes how many buffer entries we need.
		p.To.Sym = ir.Syms.GCWriteBarrier[v.AuxInt-1]
	case ssa.OpS390XLoweredPanicBoundsA, ssa.OpS390XLoweredPanicBoundsB, ssa.OpS390XLoweredPanicBoundsC:
		p := s.Prog(obj.ACALL)
		p.To.Type = obj.TYPE_MEM
		p.To.Name = obj.NAME_EXTERN

		// (InvertFlags (CMP a b)) == (CMP b a)
		// InvertFlags is a pseudo-op which can't appear in assembly output.
		{name: "InvertFlags", argLength: 1}, // reverse direction of arg0

		// LoweredWB invokes runtime.gcWriteBarrier. arg0=mem, auxint=# of buffer entries needed
		// It saves all GP registers if necessary,
		// but clobbers R14 (LR) because it's a call, and R12 which is linker trampoline scratch register.

	{name: "WBend", argLength: 1, typ: "Mem"},                  // Write barrier code is done, interrupting is now allowed.

	// WB invokes runtime.gcWriteBarrier.  This is not a normal
	// call: it takes arguments in registers, doesn't clobber
	// general-purpose registers (the exact clobber set is
	// arch-dependent), and is not a safe-point.

		{name: "LoweredNilCheck", argLength: 2, reg: regInfo{inputs: []regMask{gpsp}}, clobberFlags: true, nilCheck: true, faultOnNilArg0: true},

		// LoweredWB invokes runtime.gcWriteBarrier. arg0=mem, auxint=# of write barrier slots
		// It saves all GP registers if necessary, but may clobber others.
		// Returns a pointer to a write barrier buffer in DI.

		{name: "LoweredAtomicOr32", argLength: 3, reg: gpstore, asm: "OR", faultOnNilArg0: true, hasSideEffects: true},

		// LoweredWB invokes runtime.gcWriteBarrier. arg0=mem, auxint=# of buffer entries needed
		// It preserves R0 through R17 (except special registers R1, R2, R11, R12, R13), g, and R20 and R21,
		// but may clobber anything else, including R31 (REGTMP).