PreIncrementAssign() public static method

Creates a UnaryExpression that increments the expression by 1 and assigns the result back to the expression.
public static PreIncrementAssign ( Expression expression ) : UnaryExpression
expression Expression An to apply the operations on.
return UnaryExpression
Ejemplo n.º 1
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            public Expr ToExpression()
            {
                var exitLabel = Expr.Label();
                var loopBody  = Expr.Block(Body.ToExpression(), Expr.PreIncrementAssign(Iterator.ToExpression()));

                return(Expr.Loop(Expr.IfThenElse(Expr.LessThan(Iterator.ToExpression(), UpperBound.ToExpression()), loopBody, Expr.Break(exitLabel)), exitLabel));
            }
Ejemplo n.º 2
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        public void For(int Begin, int End, Action <LinqExpr> Body)
        {
            LinqExpr i   = DeclInit <int>(AnonymousName(), Begin);
            LinqExpr end = LinqExpr.Constant(End);

            For(() => { },
                LinqExpr.LessThan(i, end),
                () => Add(LinqExpr.PreIncrementAssign(i)),
                () => Body(i));
        }
        private UnaryExpression UnaryExpression(
            ExpressionType nodeType, System.Type type, JObject obj)
        {
            var operand = this.Prop(obj, "operand", this.Expression);
            var method  = this.Prop(obj, "method", this.Method);

            switch (nodeType)
            {
            case ExpressionType.ArrayLength: return(Expr.ArrayLength(operand));

            case ExpressionType.Convert: return(Expr.Convert(operand, type, method));

            case ExpressionType.ConvertChecked: return(Expr.ConvertChecked(operand, type, method));

            case ExpressionType.Decrement: return(Expr.Decrement(operand, method));

            case ExpressionType.Increment: return(Expr.Increment(operand, method));

            case ExpressionType.IsFalse: return(Expr.IsFalse(operand, method));

            case ExpressionType.IsTrue: return(Expr.IsTrue(operand, method));

            case ExpressionType.Negate: return(Expr.Negate(operand, method));

            case ExpressionType.NegateChecked: return(Expr.NegateChecked(operand, method));

            case ExpressionType.Not: return(Expr.Not(operand, method));

            case ExpressionType.OnesComplement: return(Expr.OnesComplement(operand, method));

            case ExpressionType.PostDecrementAssign: return(Expr.PostDecrementAssign(operand, method));

            case ExpressionType.PostIncrementAssign: return(Expr.PostIncrementAssign(operand, method));

            case ExpressionType.PreDecrementAssign: return(Expr.PreDecrementAssign(operand, method));

            case ExpressionType.PreIncrementAssign: return(Expr.PreIncrementAssign(operand, method));

            case ExpressionType.Quote: return(Expr.Quote(operand));

            case ExpressionType.Throw: return(Expr.Throw(operand, type));

            case ExpressionType.TypeAs: return(Expr.TypeAs(operand, type));

            case ExpressionType.UnaryPlus: return(Expr.UnaryPlus(operand, method));

            case ExpressionType.Unbox: return(Expr.Unbox(operand, type));

            default: throw new NotSupportedException();
            }
        }
Ejemplo n.º 4
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        public override Expr ToExpression()
        {
            var loopBody = new List <Expr>();

            if (ReadExpression.Count > 0)
            {
                loopBody.Add(Expr.Assign(AccessExpression, ReadExpression[0]));
            }

            foreach (var child in Children)
            {
                loopBody.Add(child.ToExpression());
            }

            loopBody.Add(Expr.PreIncrementAssign(Iterator));

            var loopExitLabel = Expr.Label();
            var loopCode      = Expr.Loop(Expr.IfThenElse(LoopCondition, Expr.Block(loopBody), Expr.Break(loopExitLabel)), loopExitLabel);

            return(Expr.Block(new[] { Iterator }, IteratorInitializer, loopCode));
        }
Ejemplo n.º 5
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 protected override object VisitIncrement(Increment A)
 {
     target.Add(LinqExpr.PreIncrementAssign(target.LookUp(A.Assign)));
     return(null);
 }
Ejemplo n.º 6
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        // The resulting lambda processes N samples, using buffers provided for Input and Output:
        //  void Process(int N, double t0, double T, double[] Input0 ..., double[] Output0 ...)
        //  { ... }
        private Delegate DefineProcess()
        {
            // Map expressions to identifiers in the syntax tree.
            List <KeyValuePair <Expression, LinqExpr> > inputs  = new List <KeyValuePair <Expression, LinqExpr> >();
            List <KeyValuePair <Expression, LinqExpr> > outputs = new List <KeyValuePair <Expression, LinqExpr> >();

            // Lambda code generator.
            CodeGen code = new CodeGen();

            // Create parameters for the basic simulation info (N, t, Iterations).
            ParamExpr SampleCount = code.Decl <int>(Scope.Parameter, "SampleCount");
            ParamExpr t           = code.Decl(Scope.Parameter, Simulation.t);

            // Create buffer parameters for each input...
            foreach (Expression i in Input)
            {
                inputs.Add(new KeyValuePair <Expression, LinqExpr>(i, code.Decl <double[]>(Scope.Parameter, i.ToString())));
            }

            // ... and output.
            foreach (Expression i in Output)
            {
                outputs.Add(new KeyValuePair <Expression, LinqExpr>(i, code.Decl <double[]>(Scope.Parameter, i.ToString())));
            }

            // Create globals to store previous values of inputs.
            foreach (Expression i in Input.Distinct())
            {
                AddGlobal(i.Evaluate(t_t0));
            }

            // Define lambda body.

            // int Zero = 0
            LinqExpr Zero = LinqExpr.Constant(0);

            // double h = T / Oversample
            LinqExpr h = LinqExpr.Constant(TimeStep / (double)Oversample);

            // Load the globals to local variables and add them to the map.
            foreach (KeyValuePair <Expression, GlobalExpr <double> > i in globals)
            {
                code.Add(LinqExpr.Assign(code.Decl(i.Key), i.Value));
            }

            foreach (KeyValuePair <Expression, LinqExpr> i in inputs)
            {
                code.Add(LinqExpr.Assign(code.Decl(i.Key), code[i.Key.Evaluate(t_t0)]));
            }

            // Create arrays for linear systems.
            int      M   = Solution.Solutions.OfType <NewtonIteration>().Max(i => i.Equations.Count(), 0);
            int      N   = Solution.Solutions.OfType <NewtonIteration>().Max(i => i.UnknownDeltas.Count(), 0) + 1;
            LinqExpr JxF = code.DeclInit <double[][]>("JxF", LinqExpr.NewArrayBounds(typeof(double[]), LinqExpr.Constant(M)));

            for (int j = 0; j < M; ++j)
            {
                code.Add(LinqExpr.Assign(LinqExpr.ArrayAccess(JxF, LinqExpr.Constant(j)), LinqExpr.NewArrayBounds(typeof(double), LinqExpr.Constant(N))));
            }

            // for (int n = 0; n < SampleCount; ++n)
            ParamExpr n = code.Decl <int>("n");

            code.For(
                () => code.Add(LinqExpr.Assign(n, Zero)),
                LinqExpr.LessThan(n, SampleCount),
                () => code.Add(LinqExpr.PreIncrementAssign(n)),
                () =>
            {
                // Prepare input samples for oversampling interpolation.
                Dictionary <Expression, LinqExpr> dVi = new Dictionary <Expression, LinqExpr>();
                foreach (Expression i in Input.Distinct())
                {
                    LinqExpr Va = code[i];
                    // Sum all inputs with this key.
                    IEnumerable <LinqExpr> Vbs = inputs.Where(j => j.Key.Equals(i)).Select(j => j.Value);
                    LinqExpr Vb = LinqExpr.ArrayAccess(Vbs.First(), n);
                    foreach (LinqExpr j in Vbs.Skip(1))
                    {
                        Vb = LinqExpr.Add(Vb, LinqExpr.ArrayAccess(j, n));
                    }

                    // dVi = (Vb - Va) / Oversample
                    code.Add(LinqExpr.Assign(
                                 Decl <double>(code, dVi, i, "d" + i.ToString().Replace("[t]", "")),
                                 LinqExpr.Multiply(LinqExpr.Subtract(Vb, Va), LinqExpr.Constant(1.0 / (double)Oversample))));
                }

                // Prepare output sample accumulators for low pass filtering.
                Dictionary <Expression, LinqExpr> Vo = new Dictionary <Expression, LinqExpr>();
                foreach (Expression i in Output.Distinct())
                {
                    code.Add(LinqExpr.Assign(
                                 Decl <double>(code, Vo, i, i.ToString().Replace("[t]", "")),
                                 LinqExpr.Constant(0.0)));
                }

                // int ov = Oversample;
                // do { -- ov; } while(ov > 0)
                ParamExpr ov = code.Decl <int>("ov");
                code.Add(LinqExpr.Assign(ov, LinqExpr.Constant(Oversample)));
                code.DoWhile(() =>
                {
                    // t += h
                    code.Add(LinqExpr.AddAssign(t, h));

                    // Interpolate the input samples.
                    foreach (Expression i in Input.Distinct())
                    {
                        code.Add(LinqExpr.AddAssign(code[i], dVi[i]));
                    }

                    // Compile all of the SolutionSets in the solution.
                    foreach (SolutionSet ss in Solution.Solutions)
                    {
                        if (ss is LinearSolutions)
                        {
                            // Linear solutions are easy.
                            LinearSolutions S = (LinearSolutions)ss;
                            foreach (Arrow i in S.Solutions)
                            {
                                code.DeclInit(i.Left, i.Right);
                            }
                        }
                        else if (ss is NewtonIteration)
                        {
                            NewtonIteration S = (NewtonIteration)ss;

                            // Start with the initial guesses from the solution.
                            foreach (Arrow i in S.Guesses)
                            {
                                code.DeclInit(i.Left, i.Right);
                            }

                            // int it = iterations
                            LinqExpr it = code.ReDeclInit <int>("it", Iterations);
                            // do { ... --it } while(it > 0)
                            code.DoWhile((Break) =>
                            {
                                // Solve the un-solved system.
                                Solve(code, JxF, S.Equations, S.UnknownDeltas);

                                // Compile the pre-solved solutions.
                                if (S.KnownDeltas != null)
                                {
                                    foreach (Arrow i in S.KnownDeltas)
                                    {
                                        code.DeclInit(i.Left, i.Right);
                                    }
                                }

                                // bool done = true
                                LinqExpr done = code.ReDeclInit("done", true);
                                foreach (Expression i in S.Unknowns)
                                {
                                    LinqExpr v  = code[i];
                                    LinqExpr dv = code[NewtonIteration.Delta(i)];

                                    // done &= (|dv| < |v|*epsilon)
                                    code.Add(LinqExpr.AndAssign(done, LinqExpr.LessThan(LinqExpr.Multiply(Abs(dv), LinqExpr.Constant(1e4)), LinqExpr.Add(Abs(v), LinqExpr.Constant(1e-6)))));
                                    // v += dv
                                    code.Add(LinqExpr.AddAssign(v, dv));
                                }
                                // if (done) break
                                code.Add(LinqExpr.IfThen(done, Break));

                                // --it;
                                code.Add(LinqExpr.PreDecrementAssign(it));
                            }, LinqExpr.GreaterThan(it, Zero));

                            //// bool failed = false
                            //LinqExpr failed = Decl(code, code, "failed", LinqExpr.Constant(false));
                            //for (int i = 0; i < eqs.Length; ++i)
                            //    // failed |= |JxFi| > epsilon
                            //    code.Add(LinqExpr.OrAssign(failed, LinqExpr.GreaterThan(Abs(eqs[i].ToExpression().Compile(map)), LinqExpr.Constant(1e-3))));

                            //code.Add(LinqExpr.IfThen(failed, ThrowSimulationDiverged(n)));
                        }
                    }

                    // Update the previous timestep variables.
                    foreach (SolutionSet S in Solution.Solutions)
                    {
                        foreach (Expression i in S.Unknowns.Where(i => globals.Keys.Contains(i.Evaluate(t_t0))))
                        {
                            code.Add(LinqExpr.Assign(code[i.Evaluate(t_t0)], code[i]));
                        }
                    }

                    // Vo += i
                    foreach (Expression i in Output.Distinct())
                    {
                        LinqExpr Voi = LinqExpr.Constant(0.0);
                        try
                        {
                            Voi = code.Compile(i);
                        }
                        catch (Exception Ex)
                        {
                            Log.WriteLine(MessageType.Warning, Ex.Message);
                        }
                        code.Add(LinqExpr.AddAssign(Vo[i], Voi));
                    }

                    // Vi_t0 = Vi
                    foreach (Expression i in Input.Distinct())
                    {
                        code.Add(LinqExpr.Assign(code[i.Evaluate(t_t0)], code[i]));
                    }

                    // --ov;
                    code.Add(LinqExpr.PreDecrementAssign(ov));
                }, LinqExpr.GreaterThan(ov, Zero));

                // Output[i][n] = Vo / Oversample
                foreach (KeyValuePair <Expression, LinqExpr> i in outputs)
                {
                    code.Add(LinqExpr.Assign(LinqExpr.ArrayAccess(i.Value, n), LinqExpr.Multiply(Vo[i.Key], LinqExpr.Constant(1.0 / (double)Oversample))));
                }

                // Every 256 samples, check for divergence.
                if (Vo.Any())
                {
                    code.Add(LinqExpr.IfThen(LinqExpr.Equal(LinqExpr.And(n, LinqExpr.Constant(0xFF)), Zero),
                                             LinqExpr.Block(Vo.Select(i => LinqExpr.IfThenElse(IsNotReal(i.Value),
                                                                                               ThrowSimulationDiverged(n),
                                                                                               LinqExpr.Assign(i.Value, RoundDenormToZero(i.Value)))))));
                }
            });

            // Copy the global state variables back to the globals.
            foreach (KeyValuePair <Expression, GlobalExpr <double> > i in globals)
            {
                code.Add(LinqExpr.Assign(i.Value, code[i.Key]));
            }

            LinqExprs.LambdaExpression lambda = code.Build();
            Delegate ret = lambda.Compile();

            return(ret);
        }
        private static TDelegate Simdize <T, TDelegate>(LambdaExpression expr)
            where T : unmanaged
            where TDelegate : Delegate
        {
            if (_cache.TryGetValue(expr, out var value))
            {
                return((TDelegate)value);
            }

            var simdVisitor = new SimdVisitor <T>(expr);
            var simdBody    = simdVisitor.Visit(expr.Body);

            var i   = Expr.Parameter(typeof(int), "i");
            var len = Expr.Parameter(typeof(int), "len");

            var xMemories    = expr.Parameters.Select(p => Expr.Parameter(typeof(ReadOnlyMemory <T>), p.Name)).ToArray();
            var resultMemory = Expr.Parameter(typeof(Memory <T>), "result");

            var xSpans     = xMemories.Select(p => Expr.Variable(typeof(ReadOnlySpan <T>), $"{p.Name}Span")).ToArray();
            var resultSpan = Expr.Variable(typeof(Span <T>), "resultSpan");

            var xVecSpans     = xMemories.Select(p => Expr.Variable(typeof(ReadOnlySpan <Vector <T> >), $"{p.Name}VecSpan")).ToArray();
            var resultVecSpan = Expr.Variable(typeof(Span <Vector <T> >), "resultVecSpan");

            var xSpanGetters    = xSpans.Select(p => Expr.Call(null, MemberTable._ReadOnlySpan <T> .GetItem, p, i)).ToArray();
            var xVecSpanGetters = xVecSpans.Select(p => Expr.Call(null, MemberTable._ReadOnlySpan <Vector <T> > .GetItem, p, i)).ToArray();

            var exprCall = new LambdaArgsVisitor(expr.Parameters.Zip(xSpanGetters).ToDictionary(tpl => tpl.Item1, tpl => (Expr)tpl.Item2)).Visit(expr.Body);
            var simdCall = new LambdaArgsVisitor(simdVisitor.NewArguments.Zip(xVecSpanGetters).ToDictionary(tpl => tpl.Item1, tpl => (Expr)tpl.Item2)).Visit(simdBody);

            var resultSpanSetter    = Expr.Call(null, MemberTable._Span <T> .SetItem, resultSpan, i, exprCall);
            var resultVecSpanSetter = Expr.Call(null, MemberTable._Span <Vector <T> > .SetItem, resultVecSpan, i, simdCall);

            var parameters = xMemories.Concat(new[] { resultMemory });
            var variables  = xSpans.Concat(xVecSpans).Concat(new[] { i, len, resultSpan, resultVecSpan });

            var block = new List <Expr>();

            //  xSpan = xMemory.Span;
            block.AddRange(xMemories.Zip(xSpans, (memory, span) =>
                                         Expr.Assign(
                                             span,
                                             Expr.Property(memory, MemberTable._ReadOnlyMemory <T> .Span)
                                             )
                                         ));

            //  xVecSpan = MemoryMarshal.Cast<T, Vector<T>>(xSpan);
            block.AddRange(xSpans.Zip(xVecSpans, (span, vSpan) =>
                                      Expr.Assign(
                                          vSpan,
                                          Expr.Call(null, MemberTable._MemoryMarshal.Cast <T, Vector <T> > .ForReadOnlySpan, span)
                                          )
                                      ));

            //  resultSpan = resultMemory.Span;
            block.Add(
                Expr.Assign(
                    resultSpan,
                    Expr.Property(resultMemory, MemberTable._Memory <T> .Span)
                    )
                );

            //  resultVecSpan = MemoryMarshal.Cast<T, Vector<T>>(resultSpan);
            block.Add(
                Expr.Assign(
                    resultVecSpan,
                    Expr.Call(null, MemberTable._MemoryMarshal.Cast <T, Vector <T> > .ForSpan, resultSpan)
                    )
                );

            //  for(i = 0, len = resultVecSpan.Length & ~0b1111; i < len; )
            //  {
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x0
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x1
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x2
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x3
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x4
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x5
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x6
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x7
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x8
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x9
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0xA
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0xB
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0xC
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0xD
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0xE
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0xF
            //  }
            block.Add(
                ExpressionEx.For(
                    Expr.Block(
                        Expr.Assign(i, Expr.Constant(0)),
                        Expr.Assign(
                            len,
                            Expr.And(Expr.Property(resultVecSpan, MemberTable._Span <Vector <T> > .Length), Expr.Constant(~0b1111))
                            )
                        ),
                    Expr.LessThan(i, len),
                    Expr.Empty(),
                    Expr.Block(
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x0
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x1
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x2
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x3
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x4
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x5
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x6
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x7
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x8
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x9
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0xA
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0xB
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0xC
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0xD
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0xE
                        resultVecSpanSetter, Expr.PreIncrementAssign(i)   // 0xF
                        )
                    )
                );

            //  if(i < (resultVecSpan.Length & ~0b111))
            //  {
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x0
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x1
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x2
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x3
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x4
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x5
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x6
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x7
            //  }
            block.Add(
                Expr.IfThen(
                    Expr.LessThan(
                        i,
                        Expr.And(Expr.Property(resultVecSpan, MemberTable._Span <Vector <T> > .Length), Expr.Constant(~0b111))
                        ),
                    Expr.Block(
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x0
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x1
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x2
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x3
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x4
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x5
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x6
                        resultVecSpanSetter, Expr.PreIncrementAssign(i)   // 0x7
                        )
                    )
                );

            //  if(i < (resultVecSpan.Length & ~0b11))
            //  {
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x0
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x1
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x2
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x3
            //  }
            block.Add(
                Expr.IfThen(
                    Expr.LessThan(
                        i,
                        Expr.And(Expr.Property(resultVecSpan, MemberTable._Span <Vector <T> > .Length), Expr.Constant(~0b11))
                        ),
                    Expr.Block(
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x0
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x1
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x2
                        resultVecSpanSetter, Expr.PreIncrementAssign(i)   // 0x3
                        )
                    )
                );

            //  if(i < (resultVecSpan.Length & ~0b1))
            //  {
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x0
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x1
            //  }
            block.Add(
                Expr.IfThen(
                    Expr.LessThan(
                        i,
                        Expr.And(Expr.Property(resultVecSpan, MemberTable._Span <Vector <T> > .Length), Expr.Constant(~0b1))
                        ),
                    Expr.Block(
                        resultVecSpanSetter, Expr.PreIncrementAssign(i),  // 0x0
                        resultVecSpanSetter, Expr.PreIncrementAssign(i)   // 0x1
                        )
                    )
                );

            //  if(i < resultVecSpan.Length)
            //  {
            //      resultVecSpan[i] = simdCall(xVecSpan[i], ...); ++i;  // 0x0
            //  }
            block.Add(
                Expr.IfThen(
                    Expr.LessThan(
                        i,
                        Expr.Property(resultVecSpan, MemberTable._Span <Vector <T> > .Length)
                        ),
                    Expr.Block(
                        resultVecSpanSetter, Expr.PreIncrementAssign(i)   // 0x0
                        )
                    )
                );

            //  for(i = Vector<T>.Count * resultVecSpan.Length; i < resultSpan.Length; )
            //  {
            //      resultSpan[i] = exprCall(xSpan[i], ...); ++i;
            //  }
            block.Add(
                ExpressionEx.For(
                    Expr.Assign(
                        i,
                        Expr.Multiply(
                            Expr.Constant(Vector <T> .Count),
                            Expr.Property(resultVecSpan, MemberTable._Span <Vector <T> > .Length)
                            )
                        ),
                    Expr.LessThan(i, Expr.Property(resultSpan, MemberTable._Span <T> .Length)),
                    Expr.Empty(),
                    Expr.Block(
                        resultSpanSetter, Expr.PreIncrementAssign(i)
                        )
                    )
                );
            var retval = Expr.Lambda <TDelegate>(Expr.Block(variables, block), parameters).Compile();

            _cache.TryAdd(expr, retval);
            return(retval);
        }