Simple sharing and hoisting of final field loads

Simple sharing and hoisting of final field loads

Final fields always yield the same value. Replace GetField operations with references to pevious in-scope GetField operations. If it is safe, hoist the GetField to the loop where the input is defined.

This is a temporary pass while I continue on load elimination.

R=asgerf@google.com

Committed: https://github.com/dart-lang/sdk/commit/cc0525c0c4828bd476d70c3aa1261d3c3fbc70b5

[sra1, 2015-10-30 02:37:30]

Description was changed from

==========
Simple sharing and hoisting of final field loads

Final fields always yield the same value. Replace GetField operations with
references to pevious in-scope GetField operations. If it is safe, hoist the
GetField to the loop where the input is defined.
==========

to

==========
Simple sharing and hoisting of final field loads

Final fields always yield the same value. Replace GetField operations with
references to pevious in-scope GetField operations. If it is safe, hoist the
GetField to the loop where the input is defined.

This is a temporary pass while I continue on load elimination.
==========

[sra1, 2015-10-30 02:37:30]

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

[asgerf, 2015-10-30 09:57:46]

LGTM

https://codereview.chromium.org/1415923012/diff/1/pkg/compiler/lib/src/cps_ir...
File pkg/compiler/lib/src/cps_ir/share_final_fields.dart (right):

https://codereview.chromium.org/1415923012/diff/1/pkg/compiler/lib/src/cps_ir...
pkg/compiler/lib/src/cps_ir/share_final_fields.dart:31: final Map<Primitive,
Interceptor> interceptorFor = <Primitive, Interceptor>{};
Unused field

[sra1, 2015-10-30 18:36:49]

Committed patchset #2 (id:20001) manually as
cc0525c0c4828bd476d70c3aa1261d3c3fbc70b5 (presubmit successful).