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Re: Arch-independent double-word clz expansion and a few other tweaks for bitscanning
On Sat, Aug 11, 2007 at 10:55:58AM -0700, Zack Weinberg wrote:
> I'm happy to change it around, but empirically, it doesn't seem to make
> any difference: initial RTL generation produces
>
> (insn 7 6 8 test.c:2 (parallel [
> (set (reg:CCZ 17 flags)
> (compare:CCZ (reg/v:DI 59 [ x ])
> (const_int 0 [0x0])))
> (set (reg:DI 61)
> (ctz:DI (reg/v:DI 59 [ x ])))
> ]) -1 (nil))
>
> despite that I wrote it the other way around in the insn pattern.
That's odd. But in any case, it only matters when combine tries find such
an instruction.
--
Rask Ingemann Lambertsen