Value State Dependence Graph

3 thoughts
last posted March 20, 2015, 6:22 p.m.

2 earlier thoughts

0

Compared to CFG (control-flow graph)

  • In the CFG, the procedure is broken into basic blocks, whereas in VSDG the entire procedure can be one big graph. This makes code motion simpler in VSDG as you just have to adjust the dependencies.
  • In the CFG, state dependencies are explicit, so it's hard to know whether it is safe to re-order instructions inside a basic block, or basic blocks within a procedure. In VSDG the state dependency is explicit so there is more freedom to reorder code.