static Tree.ESEQ DoExp(Tree.Expr e)
{
if (e is Tree.ESEQ)
{
return(DoExp((Tree.ESEQ)e));
}
else
{
return(ReorderExp(e));
}
}
public static StmExpList Reorder(Tree.ExpList exps)
{
if (exps == null)
{
return(NopNull);
}
else
{
Tree.Expr a = exps.Head;
if (a is Tree.CALL)
{
Temp.Temp t = new Temp.Temp();
Tree.Expr e = new Tree.ESEQ(new Tree.MOVE(new Tree.TEMP(t), a),
new Tree.TEMP(t));
return(Reorder(new Tree.ExpList(e, exps.Tail)));
}
else
{
Tree.ESEQ aa = DoExp(a);
StmExpList bb = Reorder(exps.Tail);
if (Commute(bb.Stm, aa.Exp))
{
return(new StmExpList(Seq(aa.Stm, bb.Stm),
new Tree.ExpList(aa.Exp, bb.Exps)));
}
else
{
Temp.Temp t = new Temp.Temp();
return(new StmExpList(
Seq(aa.Stm,
Seq(new Tree.MOVE(new Tree.TEMP(t), aa.Exp),
bb.Stm)),
new Tree.ExpList(new Tree.TEMP(t), bb.Exps)));
}
}
}
}
public static Tree.ESEQ ReorderExp(Tree.Expr e)
{
StmExpList x = Reorder(e.Kids());
return(new Tree.ESEQ(x.Stm, e.Build(x.Exps)));
}
static bool Commute(Tree.Stm a, Tree.Expr b)
{
return(IsNop(a) ||
b is Tree.NAME ||
b is Tree.CONST);
}
