dart2js: improve performance of TypeMask.intersection

dart2js: improve performance of TypeMask.intersection

R=asgerf@google.com

Committed: https://github.com/dart-lang/sdk/commit/f466f30fdb15ec6d3a5a79886cecb0b39f668585

[Siggi Cherem (dart-lang), 2016-01-21 01:07:12]

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

[Siggi Cherem (dart-lang), 2016-01-21 01:07:12]

https://codereview.chromium.org/1611783003/diff/1/pkg/compiler/lib/src/types/...
File pkg/compiler/lib/src/types/flat_type_mask.dart (left):

https://codereview.chromium.org/1611783003/diff/1/pkg/compiler/lib/src/types/...
pkg/compiler/lib/src/types/flat_type_mask.dart:736: if (xSubset.length <=
ySubset.length) {
this was the most important change: this was worse case quadratic (the iterable
was traverse here twice, then n times on each contains check below).

https://codereview.chromium.org/1611783003/diff/1/pkg/compiler/lib/src/types/...
File pkg/compiler/lib/src/types/union_type_mask.dart (right):

https://codereview.chromium.org/1611783003/diff/1/pkg/compiler/lib/src/types/...
pkg/compiler/lib/src/types/union_type_mask.dart:155: if (other.isUnion && this
== other) return this;
These are common cases we hit during type propagation (here and below), so I
decided to add special cases here.

Either one of these changes here or the change in FlatTypeMask was enough to
make intersection practically disappear from the profile. Together, there is
little extra benefits (4s on some local tests, but that might be within the
noise). It might still be worth including the changes here though. Thoughts? My
inclination is to add them all.

[asgerf, 2016-01-21 01:15:45]

Very nice, LGTM!

https://codereview.chromium.org/1611783003/diff/1/pkg/compiler/lib/src/types/...
File pkg/compiler/lib/src/types/union_type_mask.dart (right):

https://codereview.chromium.org/1611783003/diff/1/pkg/compiler/lib/src/types/...
pkg/compiler/lib/src/types/union_type_mask.dart:155: if (other.isUnion && this
== other) return this;
On 2016/01/21 01:07:12, Siggi Cherem (dart-lang) wrote:
> These are common cases we hit during type propagation (here and below), so I
> decided to add special cases here.
> 
> Either one of these changes here or the change in FlatTypeMask was enough to
> make intersection practically disappear from the profile. Together, there is
> little extra benefits (4s on some local tests, but that might be within the
> noise). It might still be worth including the changes here though. Thoughts?
My
> inclination is to add them all.

I say add both.

[Siggi Cherem (dart-lang), 2016-01-21 19:12:15]

Description was changed from

==========
dart2js: improve performance of TypeMask.intersection
==========

to

==========
dart2js: improve performance of TypeMask.intersection

R=asgerf@google.com

Committed:
https://github.com/dart-lang/sdk/commit/f466f30fdb15ec6d3a5a79886cecb0b39f668585
==========

[Siggi Cherem (dart-lang), 2016-01-21 19:12:16]

Committed patchset #1 (id:1) manually as
f466f30fdb15ec6d3a5a79886cecb0b39f668585 (presubmit successful).