>
> >     Here is a more-detailed review of the latest patch you sent.
> >
> >     > -      int i = 0, aligned = (intptr_t) ABLOCKS_BUSY (abase);
> >     > +      int i = 0, aligned = (ABLOCKS_BUSY (abase) != NULL);
> >
> >     Not needed for Windows 64.  The change slows the code down a bit, and
> >
> >
> > Prove it.
>
> I compiled it both ways (x86-64 GCC 4.6.2), and the "!= NULL" version
> has an extra "cmpl" instruction, so it is indeed a bit fatter.
>
>
Just for fun :

version with != NULL :

; Line 1156
xor edx, edx
 test rax, rax
lea rcx, OFFSET FLAT:free_ablock
 setne dl
add rdx, 15
 shl rdx, 10
add rdx, rdi

version without it :

; Line 1156
xor edx, edx
 lea rcx, OFFSET FLAT:free_ablock
cmp DWORD PTR [rdi+1016], edx
 setne dl
add rdx, 15
 shl rdx, 10
add rdx, rdi

cmp on one side, test on the other side.

Fabrice