// This is before the expression is processed, so ILValue's and constants havn't been assigned
public bool SimplifyTernaryOperator(IList <ILNode> body, ILBasicBlock head, int pos)
{
Debug.Assert(body.Contains(head));
// Debug.Assert((head.Body[0] as ILLabel).Name != "Block_54");
// Debug.Assert((head.Body[0] as ILLabel).Name != "L1257");
ILExpression condExpr;
ILLabel trueLabel;
ILLabel falseLabel;
ILExpression trueExpr;
ILLabel trueFall;
ILExpression falseExpr;
ILLabel falseFall;
ILLabel finalFalseFall;
ILLabel finalTrueFall;
if (head.MatchLastAndBr(GMCode.Bt, out trueLabel, out condExpr, out falseLabel) &&
labelGlobalRefCount[trueLabel] == 1 &&
labelGlobalRefCount[falseLabel] == 1 &&
labelToBasicBlock[trueLabel].MatchSingleAndBr(GMCode.Push, out trueExpr, out trueFall) &&
labelToBasicBlock[falseLabel].MatchSingleAndBr(GMCode.Push, out falseExpr, out falseFall) &&
trueFall == falseFall &&
body.Contains(labelToBasicBlock[trueFall])
// finalFall.Code == GMCode.Pop
) // (finalFall == null || finalFall.Code == GMCode.Pop)
{
ILBasicBlock trueBlock = labelToBasicBlock[trueLabel];
ILBasicBlock falseBlock = labelToBasicBlock[falseLabel];
ILBasicBlock fallBlock = labelToBasicBlock[trueFall];
ILExpression newExpr = ResolveTernaryExpression(condExpr, trueExpr, falseExpr);
head.Body.RemoveTail(GMCode.Bt, GMCode.B);
body.RemoveOrThrow(trueBlock);
body.RemoveOrThrow(falseBlock);
IList <ILExpression> finalFall;
// figure out if its a wierd short or not
if (fallBlock.MatchSingleAndBr(GMCode.Bt, out finalTrueFall, out finalFall, out finalFalseFall) &&
finalFall.Count == 0)
{
head.Body.Add(new ILExpression(GMCode.Bt, finalTrueFall, newExpr));
if (labelGlobalRefCount[trueFall] == 2)
{
body.RemoveOrThrow(fallBlock);
}
}
else if (fallBlock.Body.Count == 2) // wierd break,
{
finalFalseFall = fallBlock.GotoLabel();
head.Body.Add(new ILExpression(GMCode.Push, null, newExpr)); // we want to push it for next pass
if (labelGlobalRefCount[trueFall] == 2)
{
body.RemoveOrThrow(fallBlock);
}
}
else if (fallBlock.MatchAt(1, GMCode.Pop)) // generated? wierd instance?
{
finalFalseFall = fallBlock.EntryLabel();
error.Info("Wierd Generated Pop here", newExpr);
head.Body.Add(new ILExpression(GMCode.Push, null, newExpr));
// It should be combined in JoinBasicBlocks function
// so don't remove failblock
}
else if (fallBlock.MatchAt(1, GMCode.Assign, out finalFall)) // This is an assignment case and unsure what its for
{
finalFall.Add(newExpr);
finalFalseFall = fallBlock.EntryLabel();
}
if (finalFalseFall == null && fallBlock.MatchLastAt(1, GMCode.Ret))
{
head.Body.Add(new ILExpression(GMCode.Ret, null));
}
else
{
Debug.Assert(finalFalseFall != null);
head.Body.Add(new ILExpression(GMCode.B, finalFalseFall));
}
return(true);
}
return(false);
}