(Mod16u x y) => (Mod32u (ZeroExt16to32 x) (ZeroExt16to32 y))
(Mod8 x y) => (Mod32 (SignExt8to32 x) (SignExt8to32 y))
(Mod8u x y) => (Mod32u (ZeroExt8to32 x) (ZeroExt8to32 y))
(Mod64 x y) && buildcfg.GOPPC64 >=9 => (MODSD x y)
(Mod64 x y) && buildcfg.GOPPC64 <=8 => (SUB x (MULLD y (DIVD x y)))
(Mod64u x y) && buildcfg.GOPPC64 >= 9 => (MODUD x y)
(Mod64u x y) && buildcfg.GOPPC64 <= 8 => (SUB x (MULLD y (DIVDU x y)))

(Div8u  x y) => (DIVWU (MOVBZreg x) (MOVBZreg y))

(Hmul(64|64u) ...) => (MULH(D|DU) ...)
(Hmul32  x y) => (SRDconst [32] (MULLD (MOVWreg x) (MOVWreg y)))
(Hmul32u x y) => (SRDconst [32] (MULLD (MOVWZreg x) (MOVWZreg y)))

(Mod64 x y) => (MODD x y)
(Mod64u ...) => (MODDU ...)
// MODW/MODWU has a 64-bit dividend and a 32-bit divisor,
// so a sign/zero extension of the dividend is required.
(Mod32  x y) => (MODW  (MOVWreg x) y)