This patch fixes issues in codegen uncovered due to https://reviews.llvm.org/D26703
First, thanks for doing this.
I can find nowhere where this can possibly matter.
if (DomTreeNode *Node = DT.getNode(BB)) PQ.push(std::make_pair(Node, DomLevels.lookup(Node))); }
(the PQ is ordered anyway, and in the end, the end result ordering is irrelevant) ...)
I do not believe fixing this or iterateddominancefrontiers makes sense.
I suspect this is papering over something else, so i'll take a look.
Note that we could sort them in bb numbering order in the end if we wanted to anyway, so if we really wanted a deterministic order, we'd do that.
(This is what promotememorytoregister does)