compiler.cfg.dataflow-analysis: when intersecting sets, treat uninitialized sets as universal rather than empty; reduces number of stack instructions generated by 1%

db4
Slava Pestov 2009-08-20 18:15:41 -05:00
parent 49bd2228ec
commit 5197aca215
1 changed files with 5 additions and 1 deletions

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@ -23,7 +23,11 @@ GENERIC# compute-in-set 2 ( bb out-sets dfa -- set )
M: kill-block compute-in-set 3drop f ;
M:: basic-block compute-in-set ( bb out-sets dfa -- set )
bb dfa predecessors [ out-sets at ] map bb dfa join-sets ;
! Only consider initialized sets.
bb dfa predecessors
[ out-sets key? ] filter
[ out-sets at ] map
bb dfa join-sets ;
:: update-in-set ( bb in-sets out-sets dfa -- ? )
bb out-sets dfa compute-in-set