Re: Crashes in "C-h h"

[Paul Eggert]

Eli Zaretskii wrote:
> Is this with USE_LSB or without?  I think we need to time both
> variants.

That benchmark was with USE_LSB. I see no reason to think the !USE_LSB case 
would cause FIXNUMP+XFIXNUM to beat EQ+make_fixnum, but just to double-check 
here are the timings for that benchmark compiled with the additional GCC flags 
-m32 -DWIDE_EMACS_INT (the only significant !USE_LSB platform these days) and 
with 'long' replaced by 'long long' to get the loop to work on a 32-bit platform:

1030-lnxsrv09 $ time ./a.out 0 0

real    0m51.933s
user    0m51.927s
sys     0m0.001s
1031-lnxsrv09 $ time ./a.out 0 0 0

real    2m16.960s
user    2m16.960s
sys     0m0.000s
1032-lnxsrv09 $ time ./a.out 0 0 0 0

real    0m59.678s
user    0m59.677s
sys     0m0.001s

This indicates that on this !USE_LSB platform, the EQ+make_fixnum code is about 
ten times faster than the FIXNUMP+XFIXNUM code on this benchmark. I'm not 
surprised by the performance disparity, as branch-prediction failures can be 
pretty expensive.