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added more constfolding

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This commit is contained in:
Irmen de Jong 2021-12-09 23:32:48 +01:00
parent abca618008
commit 3d743a1ba1
4 changed files with 41 additions and 19 deletions
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24
codeOptimizers/src/prog8/optimizer/ConstantFoldingOptimizer.kt
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@ -212,21 +212,27 @@ class ConstantFoldingOptimizer(private val program: Program) : AstWalker() {
}
}
}
else if(expr.operator=="*" && leftBinExpr.operator=="*") {
else if(expr.operator=="*") {
val c2 = leftBinExpr.right.constValue(program)
if(c2!=null) {
// (X * C1) * C2 --> X * (C1*C2)
// TODO (X * C1) / C2 --> X * (C1/C2)
val constants = BinaryExpression(c2, "*", rightconst, c2.position)
val newExpr = BinaryExpression(leftBinExpr.left, "*", constants, expr.position)
return listOf(IAstModification.ReplaceNode(expr, newExpr, parent))
if(leftBinExpr.operator=="*") {
// (X * C2) * rightConst --> X * (rightConst*C2)
val constants = BinaryExpression(rightconst, "*", c2, c2.position)
val newExpr = BinaryExpression(leftBinExpr.left, "*", constants, expr.position)
return listOf(IAstModification.ReplaceNode(expr, newExpr, parent))
} else if (leftBinExpr.operator=="/") {
// (X / C2) * rightConst --> X * (rightConst/C2)
val constants = BinaryExpression(rightconst, "/", c2, c2.position)
val newExpr = BinaryExpression(leftBinExpr.left, "*", constants, expr.position)
return listOf(IAstModification.ReplaceNode(expr, newExpr, parent))
}
}
}
else if(expr.operator=="/" && leftBinExpr.operator=="/") {
else if(expr.operator=="/") {
val c2 = leftBinExpr.right.constValue(program)
if(c2!=null) {
if(c2!=null && leftBinExpr.operator=="/") {
// (X / C1) / C2 --> X / (C1*C2)
// TODO (X / C1) * C2 --> X * (C2/C1)
// NOTE: do not optimize (X * C1) / C2 --> X * (C1/C2) because this causes precision loss on integers
val constants = BinaryExpression(c2, "*", rightconst, c2.position)
val newExpr = BinaryExpression(leftBinExpr.left, "/", constants, expr.position)
return listOf(IAstModification.ReplaceNode(expr, newExpr, parent))

28
compiler/test/TestOptimization.kt
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@ -167,11 +167,12 @@ class TestOptimization: FunSpec({
val source = """
main {
sub start() {
; TODO other variants of this const folding
word llw = 300
cx16.r0s = 9 * 2 * 10 * llw
cx16.r1s = llw * 9 * 2 * 10
cx16.r2s = llw / 20 / 3
cx16.r2s = llw / 30 / 3
cx16.r3s = llw / 2 * 10
cx16.r4s = llw * 90 / 5 ; not optimized because of loss of integer division precision
}
}"""
val result = compileText(C64Target, true, source, writeAssembly = false).assertSuccess()
@ -184,9 +185,14 @@ class TestOptimization: FunSpec({
// cx16.r1s = llw
// cx16.r1s *= 180
// cx16.r2s = llw
// cx16.r2s /= 100
// cx16.r2s /= 90
// cx16.r3s = llw
// cx16.r3s *= 5
// cx16.r4s = llw
// cx16.r4s *= 90
// cx16.r4s /= 5
val stmts = result.program.entrypoint.statements
stmts.size shouldBe 8
stmts.size shouldBe 13
val mulR0Value = (stmts[3] as Assignment).value
val binexpr0 = mulR0Value as BinaryExpression
@ -199,7 +205,19 @@ class TestOptimization: FunSpec({
val divR2Value = (stmts[7] as Assignment).value
val binexpr2 = divR2Value as BinaryExpression
binexpr2.operator shouldBe "/"
binexpr2.right shouldBe NumericLiteralValue(DataType.UWORD, 60.0, Position.DUMMY)
binexpr2.right shouldBe NumericLiteralValue(DataType.UWORD, 90.0, Position.DUMMY)
val mulR3Value = (stmts[9] as Assignment).value
val binexpr3 = mulR3Value as BinaryExpression
binexpr3.operator shouldBe "*"
binexpr3.right shouldBe NumericLiteralValue(DataType.UWORD, 5.0, Position.DUMMY)
val mulR4Value = (stmts[11] as Assignment).value
val binexpr4 = mulR4Value as BinaryExpression
binexpr4.operator shouldBe "*"
binexpr4.right shouldBe NumericLiteralValue(DataType.UWORD, 90.0, Position.DUMMY)
val divR4Value = (stmts[12] as Assignment).value
val binexpr4b = divR4Value as BinaryExpression
binexpr4b.operator shouldBe "/"
binexpr4b.right shouldBe NumericLiteralValue(DataType.UWORD, 5.0, Position.DUMMY)
}
test("constantfolded and silently typecasted for initializervalues") {

1
docs/source/todo.rst
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@ -3,7 +3,6 @@ TODO
For next compiler release (7.5)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
more const-foldings
check correctness of inplaceModification_byte_value_to_pointer()
...

7
examples/test.p8
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@ -3,12 +3,11 @@
main {
sub start() {
; TODO other variants of this const folding
word llw = 300
cx16.r0s = 9 * 2 * 10 * llw
cx16.r1s = llw * 9 * 2 * 10
cx16.r2s = llw * 9 / 4
cx16.r3s = llw / 20 / 5
cx16.r4s = llw / 20 * 5
cx16.r3s = llw / 30 / 3
cx16.r4s = llw / 2 * 10
cx16.r5s = llw * 90 / 5 ; not optimized because of loss of integer division precision
}
}