APEX logd3.sac slower with AWLF than with WLF, due to WLUR
Extended Description
Created an attachment (id=857)
source code to reproduce failure
sac2c -V
sac2c v1.00-beta (Haggis And Apple)
developer rev 17747:MODIFIED linux-gnu_x86_64
(Wed Feb 29 17:00:50 EST 2012 by sac)
The benchmark above runs significantly slower ( nearly 2X)
with -doawlf -nowlf
than with -noawlf -dowlf. The apparent cause is a failure
to perform AWLF fast enough to beat WLUR to the punch:
The AWLF version shows an unrolled (1-element) WL selecting one
element from an otherwise unreferenced (and big) WL.
In the WLF version, WLF apparently folds the two WLs before
WLUR can take action.
I do not see a swell, simple way to resolve this problem.
One slightly unpleasant approach might be to extend
AWLF to operate on an unrolled consumer-WL, as if it
were a WL.