Questions about C2 IR verification

[Cesar Soares Lucas]

Hi there,

I’m working on a transformation on top of C2 IR and I’m getting an error message that's defying my C2 IR skills. This verification in PhaseIdealLoop (https://github.com/openjdk/jdk/blob/master/src%2Fhotspot%2Fshare%2Fopto%2Floopnode.cpp#L5344) is failing and I don’t understand why – AFAIU the IR graph looks correct! Would you mind taking a quick look at the graph? I placed the IR printout, IR graphs and error message here: http://cr.openjdk.java.net/~cslucas/question0/.

I think the problem might be due to incorrect setting of the control input of some nodes. When *should* a node have a *direct* control input and when can I leave it NULL and therefore have a “transitive” control?


TIA,
Cesar