Further bitop optimizations

Further bitop optimizations

- avoid unsigned coercion when result is compared with constant
- avoid unsigned coercion when result is shifted right unsigned
- avoid call when right shift result has bits affected by sign bit masked out
- use values of named constants

R=vsm@google.com

Committed: https://github.com/dart-lang/dev_compiler/commit/48d75079fbdf95db90a65ef5985863853222bb87

[sra1, 2016-05-09 05:21:54]

Description was changed from

==========
Further bitop optimizations

- avoid unsigned coercion when result is compared with constant
- avoid unsigned coercion when result is shifter right unsigned
==========

to

==========
Further bitop optimizations

- avoid unsigned coercion when result is compared with constant
- avoid unsigned coercion when result is shifted right unsigned
- avoid call when right shift result has bits affected by sign bit masked out
==========

[sra1, 2016-05-10 04:33:09]

Description was changed from

==========
Further bitop optimizations

- avoid unsigned coercion when result is compared with constant
- avoid unsigned coercion when result is shifted right unsigned
- avoid call when right shift result has bits affected by sign bit masked out
==========

to

==========
Further bitop optimizations

- avoid unsigned coercion when result is compared with constant
- avoid unsigned coercion when result is shifted right unsigned
- avoid call when right shift result has bits affected by sign bit masked out
- use values of named constants
==========

[sra1, 2016-06-03 03:37:46]

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

[sra1, 2016-06-03 03:37:47]

This CL results in a lot of good changes in the Int64 class.

[vsm, 2016-06-03 20:36:36]

lgtm

[sra1, 2016-06-03 21:29:18]

Description was changed from

==========
Further bitop optimizations

- avoid unsigned coercion when result is compared with constant
- avoid unsigned coercion when result is shifted right unsigned
- avoid call when right shift result has bits affected by sign bit masked out
- use values of named constants
==========

to

==========
Further bitop optimizations

- avoid unsigned coercion when result is compared with constant
- avoid unsigned coercion when result is shifted right unsigned
- avoid call when right shift result has bits affected by sign bit masked out
- use values of named constants

R=vsm@google.com

Committed:
https://github.com/dart-lang/dev_compiler/commit/48d75079fbdf95db90a65ef59858...
==========

[sra1, 2016-06-03 21:29:19]

Committed patchset #6 (id:100001) manually as
48d75079fbdf95db90a65ef5985863853222bb87 (presubmit successful).