Simple PHI question

[Steve Ellcey]

I have a basic GCC PHI implementation question, if a basic block has
a phi node (or a set of phi nodes) those nodes consist of a pairs of
definitions and basic block pointers.  Are the basic blocks associated
with each definition gauranteed to be direct predecessors of the block
containing the phi node? Or could the block with the definition be an
indirect predecessor of the block with the phi?  Does it matter what
pass in the compiler I am at?  I.e. maybe they start out as direct
predecessors and various optimizations could change that.

Steve Ellcey
sellcey@imgtec.com