Arch-independent double-word clz expansion and a few other tweaks for bitscanning

Mark Mitchell mark@codesourcery.com
Mon Sep 3 18:01:00 GMT 2007


Zack Weinberg wrote:
> Mark Mitchell wrote:
>> Zack Weinberg wrote:
>>
>>>     * config/i386/i386.h (CLZ_DEFINED_VALUE_AT_ZERO): Define.
>>>     * config/i386/i386.md (ffssi2, ffs_cmove, *ffs_no_cmove)
>>>     (*ffssi_1, ffsdi2, *ffsdi_1): Delete.
>>>     (*ctzsi2_ccz, *bsr_ccz, *ctzdi2_ccz, *bsr_rex64_ccz)
>>>     (*bsrhi_ccz): New insns.
>>>     (ctzdi2): Move next to clzdi2.
>>
>> This is OK.
> 
> Did you mean to overrule people's objections to this part of the patch?
>  As far as I can tell it works fine as is, but.

Thanks for asking.  And, no, I didn't mean to step on any toes; in my
reading of the previous discussion it looked like you had answered all
of the objections.  I'm sorry if I misread.

Let's leave the x86 bits out unless we hear otherwise from the x86
maintainers.

Thanks,

-- 
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713



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