On 06/08/2018 05:17 PM, Matt Wette wrote:
Andy Windo's blog on flow-analysis in Guile references Offner's "Notes on Graph Algorithms Used in Optimizing Compilers"? Anyone read this manuscript? Lemma 2.2 says, in a flow-graph, if x>>z and y>>z, then either x>>y or y>>x. The proof uses the argument that the path from s, the start, to z has to include both x and y. I'm not seeing that. Consider a graph s->x, s->y, x->z and y->z. What am I missing?
(another example, in figure 2.1 C>>K and B>>K but C and B are not ordered.)
This example does not not qualify as C and B do not dominate K. C dominates K iff every path from the start S to K goes through C.
