tree b63692e314b38556d555580143d2bacfeac926d7
parent a8d24bf578a1022ff14f89f650074dc39b9667fe
author buzbee <buzbee@google.com> 1382555799 -0700
committer buzbee <buzbee@google.com> 1382650424 -0700

Null check elimination improvement

See b/10862777

Improves the null check elimination pass by tracking visibility
of object definitions, rather than successful uses of object
dereferences.  For boot class path, increases static null
check elimination success rate from 98.4% to 98.6%.  Reduces
size of boot.oat by ~300K bytes.

Fixes loop nesting depth computation, which is used by register
promotion, and tweaked the heuristics.

Fixes a bug in verbose listing output in which a basic block
id is directly dereferenced, rather than first being converted
to a pointer.

Change-Id: Id01c20b533cdb12ea8fc4be576438407d0a34cec