dart2js cps: Overhaul PullIntoInitializers.

dart2js cps: Overhaul PullIntoInitializers.

Fixes a bug where it would pull impure expressions out of branches.

It now uses a slightly more precise analysis to pull more things into
the initializer block (but never out of branch).

BUG=
R=kmillikin@google.com

Committed: https://github.com/dart-lang/sdk/commit/919eadc29db0063bac31bd3b26e00e966ef96f9e

[asgerf, 2015-06-16 13:38:52]

asgerf@google.com changed reviewers:
+ kmillikin@google.com

[asgerf, 2015-06-17 09:40:49]

asgerf@google.com changed reviewers:
+ karlklose@google.com

[asgerf, 2015-06-17 09:40:50]

R=karlklose

[Kevin Millikin (Google), 2015-06-19 11:54:28]

LGTM.

https://codereview.chromium.org/1188783002/diff/1/pkg/compiler/lib/src/tree_i...
File pkg/compiler/lib/src/tree_ir/optimization/pull_into_initializers.dart
(right):

https://codereview.chromium.org/1188783002/diff/1/pkg/compiler/lib/src/tree_i...
pkg/compiler/lib/src/tree_ir/optimization/pull_into_initializers.dart:218: for
(int i=0; i<nodes.length; ++i) {
Missing spaces around the binary operators.

https://codereview.chromium.org/1188783002/diff/1/pkg/compiler/lib/src/tree_i...
pkg/compiler/lib/src/tree_ir/optimization/pull_into_initializers.dart:324:
++impureCounter;
Why is this impure?

[asgerf, 2015-06-19 12:08:37]

https://codereview.chromium.org/1188783002/diff/1/pkg/compiler/lib/src/tree_i...
File pkg/compiler/lib/src/tree_ir/optimization/pull_into_initializers.dart
(right):

https://codereview.chromium.org/1188783002/diff/1/pkg/compiler/lib/src/tree_i...
pkg/compiler/lib/src/tree_ir/optimization/pull_into_initializers.dart:218: for
(int i=0; i<nodes.length; ++i) {
On 2015/06/19 11:54:27, Kevin Millikin (Google) wrote:
> Missing spaces around the binary operators.

Done.

https://codereview.chromium.org/1188783002/diff/1/pkg/compiler/lib/src/tree_i...
pkg/compiler/lib/src/tree_ir/optimization/pull_into_initializers.dart:324:
++impureCounter;
On 2015/06/19 11:54:27, Kevin Millikin (Google) wrote:
> Why is this impure?

It shouldn't be. Removed.

(It was a leftover from previous version that would traverse loops, so object
creation was considered impure.)

[asgerf, 2015-06-22 10:26:28]

Committed patchset #2 (id:20001) manually as
919eadc29db0063bac31bd3b26e00e966ef96f9e (presubmit successful).