/// <summary>
/// Tries to move the assigment as far down the block as is possible.
/// </summary>
/// <param name="ass"></param>
/// <param name="block"></param>
/// <param name="i"></param>
/// <returns>true if a change was made</returns>
public bool TryMoveAssignment(Statement stmDef, SsaIdentifier sidDef, Expression defExpr, Block block, int initialPosition)
{
SideEffectFlags flagsDef = sef.FindSideEffect(stmDef.Instruction);
for (int i = initialPosition + 1; i < block.Statements.Count; ++i)
{
Statement stm = block.Statements[i];
if (sidDef.Uses.Contains(stm))
{
if (CanCoalesce(sidDef, stmDef, stm))
{
Coalesced = true;
return(CoalesceStatements(sidDef, defExpr, stmDef, stm));
}
else
{
return(MoveAssignment(initialPosition, i, block));
}
}
if (stm.Instruction.IsControlFlow)
{
return(MoveAssignment(initialPosition, i, block));
}
SideEffectFlags flagsStm = sef.FindSideEffect(stm.Instruction);
if (sef.Conflict(flagsDef, flagsStm))
{
return(MoveAssignment(initialPosition, i, block));
}
}
return(MoveAssignment(initialPosition, block.Statements.Count, block));
}
public bool Conflict(SideEffectFlags defFlags, SideEffectFlags curFlags)
{
if (defFlags == SideEffectFlags.None || curFlags == SideEffectFlags.None)
return false;
if (defFlags == SideEffectFlags.Load && curFlags == SideEffectFlags.Load)
return false;
return true;
}
public bool Conflict(SideEffectFlags defFlags, SideEffectFlags curFlags)
{
if (defFlags == SideEffectFlags.None || curFlags == SideEffectFlags.None)
{
return(false);
}
if (defFlags == SideEffectFlags.Load && curFlags == SideEffectFlags.Load)
{
return(false);
}
return(true);
}
public bool AreConstrained(Statement def, Statement use)
{
SideEffectFlags defFlags = FindSideEffect(def.Instruction);
int iUse = use.Block.Statements.IndexOf(use);
for (int i = def.Block.Statements.IndexOf(def) + 1; i < def.Block.Statements.Count; ++i)
{
if (i == iUse)
{
return(false);
}
if (Conflict(defFlags, FindSideEffect(def.Block.Statements[i].Instruction)))
{
return(true);
}
}
return(true);
}
public override void VisitApplication(Application appl)
{
base.VisitApplication(appl);
flags |= SideEffectFlags.Application;
}
public SideEffectFlags FindSideEffect(Expression e)
{
flags = SideEffectFlags.None;
e.Accept(this);
return(flags);
}
public SideEffectFlags FindSideEffect(Instruction instr)
{
flags = SideEffectFlags.None;
instr.Accept(this);
return(flags);
}
public override void VisitStore(Store store)
{
store.Dst.Accept(this);
store.Src.Accept(this);
flags |= SideEffectFlags.Store;
}
public override void VisitStore(Store store)
{
store.Dst.Accept(this);
store.Src.Accept(this);
flags |= SideEffectFlags.Store;
}
public override void VisitMemoryAccess(MemoryAccess access)
{
base.VisitMemoryAccess(access);
flags |= SideEffectFlags.Load;
}
public override void VisitMemoryAccess(MemoryAccess access)
{
base.VisitMemoryAccess(access);
flags |= SideEffectFlags.Load;
}
public override void VisitBranch(Branch b)
{
base.VisitBranch(b);
flags |= SideEffectFlags.SideEffect;
}
public override void VisitApplication(Application appl)
{
base.VisitApplication(appl);
flags |= SideEffectFlags.Application;
}
public SideEffectFlags FindSideEffect(Expression e)
{
flags = SideEffectFlags.None;
e.Accept(this);
return flags;
}
public SideEffectFlags FindSideEffect(Instruction instr)
{
flags = SideEffectFlags.None;
instr.Accept(this);
return flags;
}
public override void VisitBranch(Branch b)
{
base.VisitBranch(b);
flags |= SideEffectFlags.SideEffect;
}
public override void VisitSegmentedAccess(SegmentedAccess access)
{
base.VisitSegmentedAccess(access);
flags |= SideEffectFlags.Load;
}
public override void VisitSegmentedAccess(SegmentedAccess access)
{
base.VisitSegmentedAccess(access);
flags |= SideEffectFlags.Load;
}
