Andrew Trick 306e3d0508 Reapplying r136844. ...

An algorithm for incrementally updating LoopInfo within a
LoopPassManager. The incremental update should be extremely cheap in
most cases and can be used in places where it's not feasible to
regenerate the entire loop forest.

- "Unloop" is a node in the loop tree whose last backedge has been removed.
- Perform reverse dataflow on the block inside Unloop to propagate the
  nearest loop from the block's successors.
- For reducible CFG, each block in unloop is visited exactly
  once. This is because unloop no longer has a backedge and blocks
  within subloops don't change parents.
- Immediate subloops are summarized by the nearest loop reachable from
  their exits or exits within nested subloops.
- At completion the unloop blocks each have a new parent loop, and
  each immediate subloop has a new parent.

llvm-svn: 137276

2011-08-10 23:22:57 +00:00

..

llvm

Reapplying r136844.

2011-08-10 23:22:57 +00:00

llvm-c

Add missing file.

2011-08-09 22:19:52 +00:00