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optimize for x in something downto 0

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Irmen de Jong
2023-11-26 02:24:18 +01:00
parent 5f6cff739a
commit 44d232f52a
1 changed files with 18 additions and 0 deletions
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18
codeOptimizers/src/prog8/optimizer/StatementOptimizer.kt
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@@ -212,6 +212,24 @@ class StatementOptimizer(private val program: Program,
}
}
}
if (range != null && range.to.constValue(program)?.number == 0.0 && range.step.constValue(program)?.number==-1.0) {
val fromExpr = range.from
if(fromExpr.constValue(program)==null) {
// FOR X = something DOWNTO 0 {...} --> X=something, DO { ... , X-- } UNTIL X=255 (or 65535 if uword)
val pos = forLoop.position
val checkValue = NumericLiteral(loopvarDt.getOr(DataType.UNDEFINED), if(loopvarDt.istype(DataType.UBYTE)) 255.0 else 65535.0, pos)
val condition = BinaryExpression(forLoop.loopVar.copy(), "==", checkValue, pos)
val decOne = PostIncrDecr(AssignTarget(forLoop.loopVar.copy(), null, null, pos), "--", pos)
forLoop.body.statements.add(decOne)
val replacement = AnonymousScope(mutableListOf(
Assignment(AssignTarget(forLoop.loopVar.copy(), null, null, pos),
fromExpr, AssignmentOrigin.OPTIMIZER, pos),
UntilLoop(forLoop.body, condition, pos)
), pos)
return listOf(IAstModification.ReplaceNode(forLoop, replacement, parent))
}
}
}
return noModifications