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Simple mapping optimization fixes (#17711)
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‎docs/release-notes/.FSharp.Compiler.Service/9.0.100.md

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@@ -18,6 +18,7 @@
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* Fix IsUnionCaseTester throwing for non-methods/properties [#17301](https://github.com/dotnet/fsharp/pull/17634)
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* Consider `open type` used when the type is an enum and any of the enum cases is used unqualified. ([PR #17628](https://github.com/dotnet/fsharp/pull/17628))
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* Guard for possible StackOverflowException when typechecking non recursive modules and namespaces ([PR #17654](https://github.com/dotnet/fsharp/pull/17654))
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* Fixes for the optimization of simple mappings in array and list comprehensions. ([Issue #17708](https://github.com/dotnet/fsharp/issues/17708), [PR #17711](https://github.com/dotnet/fsharp/pull/17711))
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### Added
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‎src/Compiler/Optimize/LowerComputedCollections.fs

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@@ -373,60 +373,70 @@ module Array =
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else any ilTy
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/// Makes the equivalent of an inlined call to Array.map.
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let mkMap g m (mBody, _spFor, _spIn, mFor, mIn, spInWhile) srcArray srcIlTy destIlTy overallElemTy loopVal body =
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let len = mkLdlen g mIn srcArray
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let arrayTy = mkArrayType g overallElemTy
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/// (# "newarr !0" type ('T) count : 'T array #)
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let array =
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mkAsmExpr
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(
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[I_newarr (ILArrayShape.SingleDimensional, destIlTy)],
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[],
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[len],
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[arrayTy],
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m
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)
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let ldelem = mkIlInstr g I_ldelem (fun ilTy -> I_ldelem_any (ILArrayShape.SingleDimensional, ilTy)) srcIlTy
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let stelem = mkIlInstr g I_stelem (fun ilTy -> I_stelem_any (ILArrayShape.SingleDimensional, ilTy)) destIlTy
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let mapping =
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mkCompGenLetIn m (nameof array) arrayTy array (fun (_, array) ->
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mkCompGenLetMutableIn mFor "i" g.int32_ty (mkTypedZero g mIn g.int32_ty) (fun (iVal, i) ->
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let body =
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// Rebind the loop val to pull directly from the source array.
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let body = mkInvisibleLet mBody loopVal (mkAsmExpr ([ldelem], [], [srcArray; i], [loopVal.val_type], mBody)) body
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// destArray[i] <- body srcArray[i]
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let setArrSubI = mkAsmExpr ([stelem], [], [array; i; body], [], mIn)
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// i <- i + 1
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let incrI = mkValSet mIn (mkLocalValRef iVal) (mkAsmExpr ([AI_add], [], [i; mkTypedOne g mIn g.int32_ty], [g.int32_ty], mIn))
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mkSequential mIn setArrSubI incrI
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let guard = mkILAsmClt g mFor i (mkLdlen g mFor array)
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let mkMap g m (mBody, _spFor, _spIn, mFor, mIn, spInWhile) srcArray srcIlTy destIlTy overallElemTy (loopVal: Val) body =
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mkCompGenLetIn m (nameof srcArray) (tyOfExpr g srcArray) srcArray (fun (_, srcArray) ->
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let len = mkLdlen g mIn srcArray
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let arrayTy = mkArrayType g overallElemTy
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/// (# "newarr !0" type ('T) count : 'T array #)
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let array =
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mkAsmExpr
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(
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[I_newarr (ILArrayShape.SingleDimensional, destIlTy)],
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[],
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[len],
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[arrayTy],
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m
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)
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let loop =
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mkWhile
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g
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(
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spInWhile,
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NoSpecialWhileLoopMarker,
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guard,
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body,
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mIn
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)
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let ldelem = mkIlInstr g I_ldelem (fun ilTy -> I_ldelem_any (ILArrayShape.SingleDimensional, ilTy)) srcIlTy
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let stelem = mkIlInstr g I_stelem (fun ilTy -> I_stelem_any (ILArrayShape.SingleDimensional, ilTy)) destIlTy
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// while i < array.Length do <body> done
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// array
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mkSequential m loop array
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let mapping =
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mkCompGenLetIn m (nameof array) arrayTy array (fun (_, array) ->
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mkCompGenLetMutableIn mFor "i" g.int32_ty (mkTypedZero g mIn g.int32_ty) (fun (iVal, i) ->
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let body =
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// If the loop val is used in the loop body,
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// rebind it to pull directly from the source array.
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// Otherwise, don't bother reading from the source array at all.
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let body =
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let freeLocals = (freeInExpr CollectLocals body).FreeLocals
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if freeLocals.Contains loopVal then
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mkInvisibleLet mBody loopVal (mkAsmExpr ([ldelem], [], [srcArray; i], [loopVal.val_type], mBody)) body
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else
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body
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// destArray[i] <- body srcArray[i]
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let setArrSubI = mkAsmExpr ([stelem], [], [array; i; body], [], mIn)
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// i <- i + 1
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let incrI = mkValSet mIn (mkLocalValRef iVal) (mkAsmExpr ([AI_add], [], [i; mkTypedOne g mIn g.int32_ty], [g.int32_ty], mIn))
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mkSequential mIn setArrSubI incrI
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let guard = mkILAsmClt g mFor i (mkLdlen g mFor array)
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let loop =
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mkWhile
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g
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(
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spInWhile,
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NoSpecialWhileLoopMarker,
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guard,
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body,
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mIn
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)
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// while i < array.Length do <body> done
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// array
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mkSequential m loop array
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)
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)
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)
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// Add a debug point at the `for`, before anything gets evaluated.
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Expr.DebugPoint (DebugPointAtLeafExpr.Yes mFor, mapping)
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// Add a debug point at the `for`, before anything gets evaluated.
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Expr.DebugPoint (DebugPointAtLeafExpr.Yes mFor, mapping)
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)
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/// Whether to check for overflow when converting a value to a native int.
432442
[<NoEquality; NoComparison>]
@@ -558,6 +568,9 @@ let (|SingleYield|_|) g expr : Expr voption =
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| Expr.Sequential (expr1, DebugPoints (body, debug), kind, m) ->
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loop body (cont << fun body -> Expr.Sequential (expr1, debug body, kind, m))
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| Expr.Match (debugPoint, mInput, decision, [|TTarget (boundVals, DebugPoints (SeqSingleton g body, debug), isStateVarFlags)|], mFull, exprType) ->
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ValueSome (cont (Expr.Match (debugPoint, mInput, decision, [|TTarget (boundVals, debug body, isStateVarFlags)|], mFull, exprType)))
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| SeqSingleton g body ->
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ValueSome (cont body)
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‎tests/FSharp.Compiler.ComponentTests/EmittedIL/ComputedCollections/ForXInArray_ToArray.fs

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@@ -21,3 +21,17 @@ let f8 f g (array: int array) = [|let y = f () in let z = g () in for x in array
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let f9 f g (array: int array) = [|let y = f () in g (); for x in array -> x + y|]
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let f10 f g (array: int array) = [|f (); g (); for x in array -> x|]
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let f11 f g (array: int array) = [|f (); let y = g () in for x in array -> x + y|]
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let f12 (f: unit -> int array) y = [|for x in f () -> x + y|]
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// https://github.com/dotnet/fsharp/issues/17708
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// Don't read or rebind the loop variable when it is not in scope in the body.
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let ``for _ in Array.groupBy id [||] do ...`` () = [|for _ in Array.groupBy id [||] do 0|]
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let ``for _ | _ in Array.groupBy id [||] do ...`` () = [|for _ | _ in Array.groupBy id [||] do 0|]
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let ``for _ & _ in Array.groupBy id [||] do ...`` () = [|for _ & _ in Array.groupBy id [||] do 0|]
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let ``for _, _group in Array.groupBy id [||] do ...`` () = [|for _, _group in Array.groupBy id [||] do 0|]
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let ``for _, group in Array.groupBy id [||] do ...`` () = [|for _, group in Array.groupBy id [||] do group.Length|]
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let ``for 1 | 2 | _ in ...`` () = [|for 1 | 2 | _ in [||] do 0|]
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let ``for Failure _ | _ in ...`` () = [|for Failure _ | _ in [||] do 0|]
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let ``for true | false in ...`` () = [|for true | false in [||] do 0|]
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let ``for true | _ in ...`` () = [|for true | _ in [||] do 0|]
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let ``for _ | true in ...`` () = [|for _ | true in [||] do 0|]

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