diff options
Diffstat (limited to 'src/interp/g-opt.boot')
| -rw-r--r-- | src/interp/g-opt.boot | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/src/interp/g-opt.boot b/src/interp/g-opt.boot index be39629b..119da259 100644 --- a/src/interp/g-opt.boot +++ b/src/interp/g-opt.boot @@ -330,7 +330,18 @@ optCONDtail l == optPredicateIfTrue p => [[$true,c]] null rest l => [frst,[$true,["CondError"]]] [frst,:optCONDtail l'] - + +++ Determine whether the symbol `g' is the name of a temporary that +++ can be replaced in the form `x', if it is of linear usage and not +++ the name of a program point. The latter occurs when THROW forms +++ are changed to %LET form followed by a GO form -- see optCatch. +replaceableTemporary?(g,x) == + GENSYMP g and numOfOccurencesOf(g,x) < 2 and not jumpTarget?(g,x) where + jumpTarget?(g,x) == + isAtomicForm x => false + x is ['GO,=g] => true + or/[jumpTarget?(g,x') for x' in x] + optSEQ ["SEQ",:l] == tryToRemoveSEQ SEQToCOND getRidOfTemps splicePROGN l where splicePROGN l == @@ -339,7 +350,7 @@ optSEQ ["SEQ",:l] == l.rest := splicePROGN rest l getRidOfTemps l == null l => nil - l is [["%LET",g,x,:.],:r] and GENSYMP g and 2>numOfOccurencesOf(g,r) => + l is [["%LET",g,x],:r] and replaceableTemporary?(g,r) => getRidOfTemps substitute(x,g,r) first l="/throwAway" => getRidOfTemps rest l --this gets rid of unwanted labels generated by declarations in SEQs |