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8080: Don't stash known constants on stack

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This commit is contained in:
Karol Stasiak 2018-12-19 01:13:37 +01:00
parent 735d6c4169
commit 1b8a7c9bb3
1 changed files with 15 additions and 1 deletions
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14
src/main/scala/millfork/assembly/z80/opt/AlwaysGoodI80Optimizations.scala
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@ -300,6 +300,19 @@ object AlwaysGoodI80Optimizations {
},
)
val PointlessStackStashingFromFlow = new RuleBasedAssemblyOptimization("Pointless stack stashing from flow",
needsFlowInfo = FlowInfoRequirement.BothFlows,
// 0-4
for5LargeRegisters(register => {
(Elidable & HasOpcode(PUSH) & HasRegisterParam(register) & MatchRegister(register, 1)) ~
((Linear | HasOpcode(CALL)) & Not(HasOpcodeIn(Set(POP, PUSH))) & Not(ReadsStackPointer)).* ~
(Elidable & HasOpcode(POP) & HasRegisterParam(register)) ~~> { (code, ctx) =>
val i = ctx.get[Int](1)
code.tail.init :+ ZLine.ldImm16(register, i)
}
}),
)
private def simplifiable16BitAddWithSplitTarget(targetH: ZRegister.Value, targetL: ZRegister.Value, target: ZRegister.Value, source: ZRegister.Value) = MultipleAssemblyRules(List(
(Is8BitLoad(targetH, ZRegister.IMM_8) & MatchImmediate(1)) ~
(Linear & Not(Changes(target))).* ~
@ -1261,6 +1274,7 @@ object AlwaysGoodI80Optimizations {
PointlessFlagChange,
PointlessLoad,
PointlessStackStashing,
PointlessStackStashingFromFlow,
ReloadingKnownValueFromMemory,
ShiftingKnownValue,
SimplifiableMaths,