On Thu, Sep 9, 2010 at 7:24 AM, Richard Guenther <richard.guent...@gmail.com> wrote: > On Thu, Sep 9, 2010 at 1:19 PM, Amker.Cheng <amker.ch...@gmail.com> wrote: >> Hi, >> I am studying gcc's points-to analysis right now and encountered a question. >> In paper "Off-line Variable Substitution for Scaling Points-to >> Analysis", section 3.2 >> It says that we should not substitute a variable with other if it is >> taken address. > and How gcc keeps accuracy of points-to >> information after doing this. In theory, this is true, but a lot of the optimizations decrease accuracy at a cost of making the problem solvable in a reasonable amount of time. By performing it after building initial points-to sets, the amount of accuracy loss is incredibly small. The only type of constraint that will generate inaccuracy at that point is a complex address taken with offset one, which is pretty rare. On the other hand, *not* doing it will make the problem take forever to solve :)
What's better, something that gives correct but slightly conservative answers in 10s, or something that gives correct and 1% less conservative answers in 200s?
