tree 0684e7dd7ca2768991a839a5ddbe78f20bf1e4bf
parent 76f1413492c228bfa710e1eaa4c60370eaffbb8a
author Mingyao Yang <mingyao@google.com> 1428968788 -0700
committer Mingyao Yang <mingyao@google.com> 1430070421 -0700

Deoptimization-based BCE for unknown loop bounds.

For loop like:
  for (int i = start; i < end; i++) {
    array[i] = 1;
  }
We add the following to the loop pre-header:
  if (start < 0) deoptimize();
  if (end > array.length) deoptimize();
Then we can eliminate bounds-check of array[i] inside the loop.

We also take care of indexing with induction variable plus some offsets,
like array[i - 1]/array[i + 1] inside the loop, and adjust the condition
for deoptimization accordingly.

Change-Id: I9e24c6b5e134ff95eff5b5605ff8f95d6546616f