[PATCH] [Polly][Refactor] Generalize parallel code generation

[Tobias Grosser]

I like the idea with the DataLayout. This makes the behaviour a lot more clear. Thanks for insisting here.

You also sneaked in a semantic change without a test case (actually it can not be tested as the current CLooG code generator always generates matching types making this basically dead code). I would feel more comfortable if we remove such asserts only when needed and with a specific test case and explaining why truncating is OK, instead of having this part of a larger refactoring.

	​ if (LB->getType() != LongType)
	​ LB = Builder.CreateSExtOrTrunc(LB, LongType);
	​ if (UB->getType() != LongType)
	​ UB = Builder.CreateSExtOrTrunc(UB, LongType);
	​ if (Stride->getType() != LongType)
	​ Stride = Builder.CreateSExtOrTrunc(Stride, LongType);

Otherwise LGTM.

http://reviews.llvm.org/D4990