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Re: [patch] Use bit scanning and counting builtins for std::bitset


On Sun, 2 Feb 2003 13:19:39 -0500
Phil Edwards <phil@jaj.com> wrote:

>On Sun, Feb 02, 2003 at 03:34:34AM +0100, Falk Hueffner wrote:
>> this patch utilizes gcc's builtin functions for bit counting and
>> scanning.  With it, I can achieve a speedup of 32% for a toy program
>> of mine (by using the Alpha "ctpop" instruction).
>
>Nice.  I'm the middle of ugly stuff right now, but I'll look closer at
>the patch tomorrow.

Agreed. I'll let you take care of this.

FYI config/link-map.gnu's export of  std::_S_bit_count can now be
removed.

Formatting issues:

-	while ( __byte_ptr < __end_ptr )

should be
-	while (__byte_ptr < __end_ptr)


and

-	      // find byte within word

should be
-	      // Find byte within word.


also, it might be possible to completely eliminate the macro CHAR_BIT
now. If possible, this should be done.

Phil, you might want to try and port this back to 3.2/3.3.

-benjamin


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