IA-64 anti-dependence stalls

[Stephen Clarke]

In the minutes of the IA-64 gcc summit at

http://linuxia64.org/gcc_summit.2001.06.06.html

the following was listed as "Unfinished and/or abandoned work":

>  - A new pass to use more registers to avoid an anti-dependence stall in
>    Itanium that David Mosberger discovered.
> 
>    The new pass uses more registers.  By default the register allocator
>    will use as few registers as possible, which isn't always the right
>    thing to do.  This change resulted in very measurable speed-ups of
>    5-6% when using more registers on IPF.

We're doing some microarchitecture experiments that may benefit from this
idea -- can anyone provide more information on what was done, and
whether this code is public?

Thanks,
Steve.
-- 
Stephen Clarke, Micro Cores & Development Tools, STMicroelectronics
Phone:1-408-922-4062, Fax:1-408-895-3069, mailto:Stephen.Clarke@st.com
Mail:  STMicroelectronics, 1060 E. Brokaw Rd., San Jose, CA 95131.