dart2js: eliminate redundant stores

dart2js: eliminate redundant stores

BUG=
R=sigmund@google.com

Committed: https://github.com/dart-lang/sdk/commit/9ab56a9bb639d6d58b2ea586c490180a2b9491ae

[sra1, 2017-04-08 20:16:20]

Patchset #1 (id:1) has been deleted

[sra1, 2017-04-28 03:55:25]

sra@google.com changed reviewers:
+ sigmund@google.com

[sra1, 2017-04-28 03:55:25]

Back-to-back writes of the same value are not common but we can detect some of
them easily.

80 hits in a certain large angular app.

[Siggi Cherem (dart-lang), 2017-04-28 22:22:39]

lgtm

https://codereview.chromium.org/2810493002/diff/20001/pkg/compiler/lib/src/ss...
File pkg/compiler/lib/src/ssa/optimize.dart (right):

https://codereview.chromium.org/2810493002/diff/20001/pkg/compiler/lib/src/ss...
pkg/compiler/lib/src/ssa/optimize.dart:2632:
nonEscapingReceivers.remove(value.nonCheck());
if the assignments is redundant, would the kill here be already done as well?
Could we skip it?

[sra1, 2017-04-28 23:25:24]

https://codereview.chromium.org/2810493002/diff/20001/pkg/compiler/lib/src/ss...
File pkg/compiler/lib/src/ssa/optimize.dart (right):

https://codereview.chromium.org/2810493002/diff/20001/pkg/compiler/lib/src/ss...
pkg/compiler/lib/src/ssa/optimize.dart:2632:
nonEscapingReceivers.remove(value.nonCheck());
On 2017/04/28 22:22:38, Siggi Cherem (dart-lang) wrote:
> if the assignments is redundant, would the kill here be already done as well?
> Could we skip it?

I would expect so, but it is not worth skipping.
I want to factor out the nonEscapingReceivers into a separate aliasing analysis
that runs before load elimination.

[sra1, 2017-04-28 23:38:21]

Description was changed from

==========
dart2js: eliminate redundant stores

BUG=
==========

to

==========
dart2js: eliminate redundant stores

BUG=
R=sigmund@google.com

Committed:
https://github.com/dart-lang/sdk/commit/9ab56a9bb639d6d58b2ea586c490180a2b9491ae
==========

[sra1, 2017-04-28 23:38:22]

Committed patchset #1 (id:20001) manually as
9ab56a9bb639d6d58b2ea586c490180a2b9491ae (presubmit successful).