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6809: Fix and improve optimizations

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This commit is contained in:
Karol Stasiak 2021-05-05 02:58:28 +02:00
parent fcdad413b0
commit c51c08ad56
2 changed files with 23 additions and 6 deletions
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13
src/main/scala/millfork/assembly/m6809/opt/AlwaysGoodMOptimizations.scala
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@ -19,15 +19,23 @@ object AlwaysGoodMOptimizations {
(Elidable & HasOpcodeIn(LDX, LEAX) & DoesntMatterWhatItDoesWith(MState.X, MState.NF, MState.ZF, MState.VF)) ~~> (_ => Nil),
(Elidable & HasOpcodeIn(LDY, LEAY) & DoesntMatterWhatItDoesWith(MState.Y, MState.NF, MState.ZF, MState.VF)) ~~> (_ => Nil),
(Elidable & HasOpcode(STB) & MatchAddrMode(0) & MatchParameter(1)) ~
(Linear & Not(ChangesB) & DoesntChangeIndexingInAddrMode(0)).* ~
(Linear & Not(ChangesB) & DoesntChangeIndexingInAddrMode(0) & DoesntChangeMemoryAt(0, 1)).* ~
(Elidable & HasOpcode(LDB) & MatchAddrMode(0) & MatchParameter(1)
& DoesntMatterWhatItDoesWith(MState.NF, MState.ZF, MState.VF)) ~~> (_.init),
(Elidable & HasOpcode(STD) & MatchAddrMode(0) & MatchParameter(1)) ~
(Linear & Not(ChangesB) & DoesntChangeIndexingInAddrMode(0)).* ~
(Linear & Not(ChangesB) & Not(ChangesA) & DoesntChangeIndexingInAddrMode(0) & DoesntChangeMemoryAt(0, 1)).* ~
(Elidable & HasOpcode(LDD) & MatchAddrMode(0) & MatchParameter(1)
& DoesntMatterWhatItDoesWith(MState.NF, MState.ZF, MState.VF)) ~~> (_.init),
)
val PointlessCompare = new RuleBasedAssemblyOptimization("Pointless compare",
needsFlowInfo = FlowInfoRequirement.BackwardFlow,
(HasOpcodeIn(LDA, ANDA, ORA, EORA, ADDA, ADCA, SUBA, SBCA)) ~ DebugMatching ~
(Elidable & HasOpcode(CMPA) & HasImmediate(0) & DoesntMatterWhatItDoesWith(MState.VF, MState.CF, MState.HF)) ~ DebugMatching ~~> {code => code.init},
(HasOpcodeIn(LDB, ANDB, ORB, EORB, ADDB, ADCB, SUBB, SBCB)) ~ DebugMatching ~
(Elidable & HasOpcode(CMPB) & HasImmediate(0) & DoesntMatterWhatItDoesWith(MState.VF, MState.CF, MState.HF)) ~ DebugMatching ~~> {code => code.init},
)
val SimplifiableZeroStore = new RuleBasedAssemblyOptimization("Simplifiable zero store",
needsFlowInfo = FlowInfoRequirement.BothFlows,
(Elidable & HasOpcode(LDA) & HasImmediate(0) & DoesntMatterWhatItDoesWith(MState.CF)) ~~> {
@ -149,6 +157,7 @@ object AlwaysGoodMOptimizations {
val All: Seq[AssemblyOptimization[MLine]] = Seq(
PointlessLoad,
PointlessCompare,
PointlessRegisterTransfers,
SimplifiableArithmetics,
SimplifiableJumps,

16
src/main/scala/millfork/assembly/m6809/opt/ReverseFlowAnalyzer.scala
View File

@ -1,5 +1,6 @@
package millfork.assembly.m6809.opt
import jdk.jfr.BooleanFlag
import millfork.assembly._
import millfork.assembly.m6809.{Absolute, MLine, MLine0, MOpcode, MState}
import millfork.assembly.opt.FlowCache
@ -97,7 +98,7 @@ object ReverseFlowAnalyzer {
private val finalImportance: CpuImportance = CpuImportance(
a = Important, b = Important,
x = Important, y = Important, u = Important,
cf = Important, vf = Important, hf = Important, zf = Important, nf = Important)
cf = Unimportant, vf = Unimportant, hf = Unimportant, zf = Unimportant, nf = Unimportant)
//noinspection RedundantNewCaseClass
def analyze(f: NormalFunction, code: List[MLine], optimizationContext: OptimizationContext): List[CpuImportance] = {
@ -108,9 +109,14 @@ object ReverseFlowAnalyzer {
var changed = true
changed = true
val actualFinalImportance = f.returnType match {
case FlagBooleanType(_, _, _) => finalImportance.copy(cf = Important, zf =Important, nf = Important, vf = Important)
case t if t.size == 1 => finalImportance.copy(a = Unimportant)
case _ => finalImportance
}
while (changed) {
changed = false
var currentImportance = finalImportance
var currentImportance = actualFinalImportance
for (i <- codeArray.indices.reverse) {
import millfork.assembly.m6809.MOpcode._
import millfork.node.M6809NiceFunctionProperty._
@ -126,11 +132,13 @@ object ReverseFlowAnalyzer {
case MLine0(LABEL, _, MemoryAddressConstant(Label(L))) => true
case _ => false
}
currentImportance = if (labelIndex < 0) finalImportance else importanceArray(labelIndex) ~ currentImportance
currentImportance = if (labelIndex < 0) actualFinalImportance else importanceArray(labelIndex) ~ currentImportance
case _ =>
}
currentLine match {
case MLine0(RTS, _, _) =>
currentImportance = actualFinalImportance
case MLine0(JSR | JMP, Absolute(false), MemoryAddressConstant(fun: FunctionInMemory)) =>
// this case has to be handled first, because the generic JSR importance handler is too conservative
var result = importanceBeforeJsr
@ -173,7 +181,7 @@ object ReverseFlowAnalyzer {
case MLine0(opcode, addrMode, _) =>
if (MOpcode.ChangesC(opcode)) currentImportance = currentImportance.copy(cf = Unimportant)
if (MOpcode.ChangesN(opcode)) currentImportance = currentImportance.copy(nf = Unimportant)
if (MOpcode.ChangesZ(opcode)) currentImportance = currentImportance.copy(zf = Unimportant)
if (MOpcode.ChangesH(opcode)) currentImportance = currentImportance.copy(hf = Unimportant)
if (MOpcode.ChangesZ(opcode)) currentImportance = currentImportance.copy(zf = Unimportant)
if (MOpcode.ReadsC(opcode)) currentImportance = currentImportance.copy(cf = Important)
if (MOpcode.ReadsH(opcode)) currentImportance = currentImportance.copy(hf = Important)