[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: flow-analysis and Offner's notes

From: Matt Wette
Subject: Re: flow-analysis and Offner's notes
Date: Sat, 9 Jun 2018 06:34:49 -0700
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0

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.

reply via email to

[Prev in Thread] Current Thread [Next in Thread]