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optimize conditional expression WORD & $ff00 to just msb(WORD)&$ff

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This commit is contained in:
Irmen de Jong
2022-08-11 23:43:05 +02:00
parent d6b8936376
commit 18790d867c
6 changed files with 46 additions and 13 deletions
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19
codeOptimizers/src/prog8/optimizer/ExpressionSimplifier.kt
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@@ -10,13 +10,14 @@ import prog8.ast.statements.*
import prog8.ast.walk.AstWalker
import prog8.ast.walk.IAstModification
import prog8.code.core.*
import prog8.code.target.VMTarget
import kotlin.math.abs
import kotlin.math.log2
import kotlin.math.pow
// TODO add more peephole expression optimizations? Investigate what optimizations binaryen has, also see https://egorbo.com/peephole-optimizations.html
class ExpressionSimplifier(private val program: Program) : AstWalker() {
class ExpressionSimplifier(private val program: Program, private val compTarget: ICompilationTarget) : AstWalker() {
private val powersOfTwo = (1..16).map { (2.0).pow(it) }.toSet()
private val negativePowersOfTwo = powersOfTwo.map { -it }.toSet()
@@ -71,6 +72,22 @@ class ExpressionSimplifier(private val program: Program) : AstWalker() {
}
}
}
if(compTarget.name!=VMTarget.NAME) {
val booleanCondition = ifElse.condition as? BinaryExpression
if(booleanCondition!=null && booleanCondition.operator=="&") {
// special optimization of WORD & $ff00 -> just and the msb of WORD with $ff
val rightNum = booleanCondition.right as? NumericLiteral
if(rightNum!=null && rightNum.type==DataType.UWORD && (rightNum.number.toInt() and 0x00ff)==0) {
val msb = BuiltinFunctionCall(IdentifierReference(listOf("msb"), booleanCondition.left.position), mutableListOf(booleanCondition.left), booleanCondition.left.position)
val bytevalue = NumericLiteral(DataType.UBYTE, (rightNum.number.toInt() shr 8).toDouble(), booleanCondition.right.position)
return listOf(
IAstModification.ReplaceNode(booleanCondition.left, msb, booleanCondition),
IAstModification.ReplaceNode(booleanCondition.right, bytevalue, booleanCondition))
}
}
}
return noModifications
}

4
codeOptimizers/src/prog8/optimizer/Extensions.kt
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@@ -60,8 +60,8 @@ fun Program.inlineSubroutines(): Int {
return inliner.applyModifications()
}
fun Program.simplifyExpressions() : Int {
val opti = ExpressionSimplifier(this)
fun Program.simplifyExpressions(target: ICompilationTarget) : Int {
val opti = ExpressionSimplifier(this, target)
opti.visit(this)
return opti.applyModifications()
}