question of RTL Generation

[Hsin-Hsien Wu]

Hello,

Here is a RTL generated by gcc.
(insn 807 806 812 88 0x401639a0 (set (mem:DI (reg:SI 22 r22 [2]) [2 S8 A32])
        (reg/v:DI 16 r16 [65])) 107 {*target_movdi} (nil)
    (nil))

I don't want the register allocator to allocate the regs (regs >15) as a
memory index or base register.
(insn 807 806 812 88 0x401639a0 (set (mem:DI (reg:SI 22 r22 [2]) [2 S8 A32])

^____ I don't want r22 to be allocated here.

Does any one have the idea ?

Thanks

Mike Wu