RSB	R0->28, R1           // 401e61e0
	RSB	R0@>28, R1           // 601e61e0
	RSB.S	R0<<28, R1           // 001e71e0
	RSB.S	R0>>28, R1           // 201e71e0
	RSB.S	R0->28, R1           // 401e71e0
	RSB.S	R0@>28, R1           // 601e71e0
	RSB	R0<<R1, R2, R3       // 103162e0
	RSB	R0>>R1, R2, R3       // 303162e0
	RSB	R0->R1, R2, R3       // 503162e0
	RSB	R0@>R1, R2, R3       // 703162e0

(SUBS (SRA y z) x) => (RSBSshiftRAreg x y z)
(RSB x (SLLconst [c] y)) => (RSBshiftLL x y [c])
(RSB (SLLconst [c] y) x) => (SUBshiftLL x y [c])
(RSB x (SRLconst [c] y)) => (RSBshiftRL x y [c])
(RSB (SRLconst [c] y) x) => (SUBshiftRL x y [c])
(RSB x (SRAconst [c] y)) => (RSBshiftRA x y [c])
(RSB (SRAconst [c] y) x) => (SUBshiftRA x y [c])
(RSB x (SLL y z)) => (RSBshiftLLreg x y z)
(RSB (SLL y z) x) => (SUBshiftLLreg x y z)

			r = rt
		}
		x, y := immrot2a(uint32(c.instoffset))
		var as2 obj.As
		switch p.As {
		case AADD, ASUB, AORR, AEOR, ABIC:
			as2 = p.As // ADD, SUB, ORR, EOR, BIC
		case ARSB:
			as2 = AADD // RSB -> RSB/ADD pair
		case AADC:
			as2 = AADD // ADC -> ADC/ADD pair
		case ASBC:
			as2 = ASUB // SBC -> SBC/SUB pair
		case ARSC:
			as2 = AADD // RSC -> RSC/ADD pair
		default: