protected internal override void VisitIfInstruction(IfInstruction inst)
{
inst.TrueInst.AcceptVisitor(this);
inst.FalseInst.AcceptVisitor(this);
inst = HandleConditionalOperator(inst);
// Bring LogicAnd/LogicOr into their canonical forms:
// if (cond) ldc.i4 0 else RHS --> if (!cond) RHS else ldc.i4 0
// if (cond) RHS else ldc.i4 1 --> if (!cond) ldc.i4 1 else RHS
// Be careful: when both LHS and RHS are the constant 1, we must not
// swap the arguments as it would lead to an infinite transform loop.
if (inst.TrueInst.MatchLdcI4(0) && !inst.FalseInst.MatchLdcI4(0) ||
inst.FalseInst.MatchLdcI4(1) && !inst.TrueInst.MatchLdcI4(1))
{
context.Step("canonicalize logic and/or", inst);
var t = inst.TrueInst;
inst.TrueInst = inst.FalseInst;
inst.FalseInst = t;
inst.Condition = Comp.LogicNot(inst.Condition);
}
// Process condition after our potential modifications.
inst.Condition.AcceptVisitor(this);
if (new NullableLiftingTransform(context).Run(inst))
{
return;
}
if (TransformDynamicAddAssignOrRemoveAssign(inst))
{
return;
}
if (inst.MatchIfInstructionPositiveCondition(out var condition, out var trueInst, out var falseInst))
{
ILInstruction transformed = UserDefinedLogicTransform.Transform(condition, trueInst, falseInst);
if (transformed == null)
{
transformed = UserDefinedLogicTransform.TransformDynamic(condition, trueInst, falseInst);
}
if (transformed != null)
{
context.Step("User-defined short-circuiting logic operator (roslyn pattern)", condition);
transformed.AddILRange(inst);
inst.ReplaceWith(transformed);
return;
}
}
if (MatchInstruction.IsPatternMatch(inst.Condition, out _) &&
inst.TrueInst.MatchLdcI4(1) && inst.FalseInst.MatchLdcI4(0))
{
context.Step("match(x) ? true : false -> match(x)", inst);
inst.Condition.AddILRange(inst);
inst.ReplaceWith(inst.Condition);
return;
}
}
/// <summary>
/// Inlines 'expr' into 'next', if possible.
///
/// Note that this method does not check whether 'v' has only one use;
/// the caller is expected to validate whether inlining 'v' has any effects on other uses of 'v'.
/// </summary>
static bool DoInline(ILVariable v, ILInstruction inlinedExpression, ILInstruction next, InliningOptions options, ILTransformContext context)
{
var r = FindLoadInNext(next, v, inlinedExpression, options);
if (r.Type == FindResultType.Found || r.Type == FindResultType.NamedArgument)
{
var loadInst = r.LoadInst;
if (loadInst.OpCode == OpCode.LdLoca)
{
if (!IsGeneratedValueTypeTemporary((LdLoca)loadInst, v, inlinedExpression))
{
return(false);
}
}
else
{
Debug.Assert(loadInst.OpCode == OpCode.LdLoc);
bool aggressive = (options & InliningOptions.Aggressive) != 0;
if (!aggressive && v.Kind != VariableKind.StackSlot &&
!NonAggressiveInlineInto(next, r, inlinedExpression, v))
{
return(false);
}
}
if (r.Type == FindResultType.NamedArgument)
{
NamedArgumentTransform.IntroduceNamedArgument(r.CallArgument, context);
// Now that the argument is evaluated early, we can inline as usual
}
context.Step($"Inline variable '{v.Name}'", inlinedExpression);
// Assign the ranges of the ldloc instruction:
inlinedExpression.AddILRange(loadInst);
if (loadInst.OpCode == OpCode.LdLoca)
{
// it was an ldloca instruction, so we need to use the pseudo-opcode 'addressof'
// to preserve the semantics of the compiler-generated temporary
Debug.Assert(((LdLoca)loadInst).Variable == v);
loadInst.ReplaceWith(new AddressOf(inlinedExpression, v.Type));
}
else
{
loadInst.ReplaceWith(inlinedExpression);
}
return(true);
}
return(false);
}
/// <summary>
/// Inlines 'expr' into 'next', if possible.
///
/// Note that this method does not check whether 'v' has only one use;
/// the caller is expected to validate whether inlining 'v' has any effects on other uses of 'v'.
/// </summary>
static bool DoInline(ILVariable v, ILInstruction inlinedExpression, ILInstruction next, InliningOptions options, ILTransformContext context)
{
var r = FindLoadInNext(next, v, inlinedExpression, out var loadInst);
if (r == FindResult.Found)
{
if (loadInst.OpCode == OpCode.LdLoca)
{
if (!IsGeneratedValueTypeTemporary(next, (LdLoca)loadInst, v, inlinedExpression))
{
return(false);
}
}
else
{
Debug.Assert(loadInst.OpCode == OpCode.LdLoc);
bool aggressive = (options & InliningOptions.Aggressive) != 0;
if (!aggressive && v.Kind != VariableKind.StackSlot &&
!NonAggressiveInlineInto(next, loadInst, inlinedExpression, v))
{
return(false);
}
}
context.Step($"Inline variable '{v.Name}'", inlinedExpression);
// Assign the ranges of the ldloc instruction:
inlinedExpression.AddILRange(loadInst.ILRange);
if (loadInst.OpCode == OpCode.LdLoca)
{
// it was an ldloca instruction, so we need to use the pseudo-opcode 'addressof'
// to preserve the semantics of the compiler-generated temporary
loadInst.ReplaceWith(new AddressOf(inlinedExpression));
}
else
{
loadInst.ReplaceWith(inlinedExpression);
}
return(true);
}
else if (r == FindResult.NamedArgument && (options & InliningOptions.IntroduceNamedArguments) != 0)
{
return(NamedArgumentTransform.DoInline(v, (StLoc)inlinedExpression.Parent, (LdLoc)loadInst,
options, context));
}
return(false);
}
/// <summary>
/// Inlines 'expr' into 'next', if possible.
///
/// Note that this method does not check whether 'v' has only one use;
/// the caller is expected to validate whether inlining 'v' has any effects on other uses of 'v'.
/// </summary>
static bool DoInline(ILVariable v, ILInstruction inlinedExpression, ILInstruction next, bool aggressive, ILTransformContext context)
{
ILInstruction loadInst;
if (FindLoadInNext(next, v, inlinedExpression, out loadInst) == true)
{
if (loadInst.OpCode == OpCode.LdLoca)
{
if (!IsGeneratedValueTypeTemporary(next, loadInst.Parent, loadInst.ChildIndex, v, inlinedExpression))
{
return(false);
}
}
else
{
Debug.Assert(loadInst.OpCode == OpCode.LdLoc);
if (!aggressive && v.Kind != VariableKind.StackSlot && !NonAggressiveInlineInto(next, loadInst, inlinedExpression, v))
{
return(false);
}
}
context.Step($"Inline variable '{v.Name}'", inlinedExpression);
// Assign the ranges of the ldloc instruction:
inlinedExpression.AddILRange(loadInst.ILRange);
if (loadInst.OpCode == OpCode.LdLoca)
{
// it was an ldloca instruction, so we need to use the pseudo-opcode 'addressof'
// to preserve the semantics of the compiler-generated temporary
loadInst.ReplaceWith(new AddressOf(inlinedExpression));
}
else
{
loadInst.ReplaceWith(inlinedExpression);
}
return(true);
}
return(false);
}