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added a few more comparison expression optimizations

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This commit is contained in:
Irmen de Jong 2023-03-04 15:49:58 +01:00
parent 448d176c24
commit 1436480eab
2 changed files with 25 additions and 7 deletions
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25
codeOptimizers/src/prog8/optimizer/ExpressionSimplifier.kt
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@ -187,12 +187,37 @@ class ExpressionSimplifier(private val program: Program,
}
}
// X <= Y-1 ---> X<Y , X >= Y+1 ---> X>Y
if(leftDt in IntegerDatatypes && rightDt in IntegerDatatypes) {
val rightExpr = expr.right as? BinaryExpression
if(rightExpr!=null && rightExpr.right.constValue(program)?.number==1.0) {
if (expr.operator == "<=" && rightExpr.operator == "-") {
expr.operator = "<"
return listOf(IAstModification.ReplaceNode(rightExpr, rightExpr.left, expr))
} else if (expr.operator == ">=" && rightExpr.operator == "+") {
expr.operator = ">"
return listOf(IAstModification.ReplaceNode(rightExpr, rightExpr.left, expr))
}
}
}
if(leftDt!=DataType.FLOAT && expr.operator == ">=" && rightVal?.number == 1.0) {
// for integers: x >= 1 --> x > 0
expr.operator = ">"
return listOf(IAstModification.ReplaceNode(expr.right, NumericLiteral.optimalInteger(0, expr.right.position), expr))
}
// for signed integers: X <= -1 => X<0 , X > -1 => X>=0
if(leftDt in SignedDatatypes && leftDt!=DataType.FLOAT && rightVal?.number==-1.0) {
if(expr.operator=="<=") {
expr.operator = "<"
return listOf(IAstModification.ReplaceNode(expr.right, NumericLiteral(rightDt, 0.0, expr.right.position), expr))
} else if(expr.operator==">") {
expr.operator = ">="
return listOf(IAstModification.ReplaceNode(expr.right, NumericLiteral(rightDt, 0.0, expr.right.position), expr))
}
}
if (leftDt == DataType.UBYTE || leftDt == DataType.UWORD) {
if(expr.operator == ">=" && rightVal?.number == 0.0) {
// unsigned >= 0 --> true

7
docs/source/todo.rst
View File

@ -3,13 +3,6 @@ TODO
For next minor release
^^^^^^^^^^^^^^^^^^^^^^
- add optimizations for integer X <= Y-1 ---> X<Y , X >= Y+1 ---> X>Y
- add optimizations for integer:
X >= 1 => X > 0 (signed and unsigned)
X < 1 => X <= 0 (signed) or X==0 (unsigned)
X <= -1 => X >= 0 (signed only)
X > -1 => X >= 0 (signed only)
...