Track users through phi nodes to eliminate '>>> 0' for more bitops whose results are only used in other bitops.
Track users through phi nodes to eliminate '>>> 0' for more bitops
whose results are only used in other bitops.

R=kasperl@google.com,sgjesse@google.com
BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com//10695103

git-svn-id: c93d8a2297af3b929165606efe145742a534bc71@9413 260f80e4-7a28-3924-810f-c04153c831b5

dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk