Add a helper to add a LetPrim node for a new primitive node.

Add a helper to add a LetPrim node for a new primitive node.

R=kmillikin@google.com

Committed: https://code.google.com/p/dart/source/detail?r=44571

[Kevin Millikin (Google), 2015-03-18 12:50:41]

If you make the following changes, it LGTM.

https://codereview.chromium.org/1010423002/diff/1/pkg/compiler/lib/src/cps_ir...
File pkg/compiler/lib/src/cps_ir/cps_ir_builder.dart (right):

https://codereview.chromium.org/1010423002/diff/1/pkg/compiler/lib/src/cps_ir...
pkg/compiler/lib/src/cps_ir/cps_ir_builder.dart:440: /// Create and add a new
[LetPrim] for [expression].
Call the argument primitive.

https://codereview.chromium.org/1010423002/diff/1/pkg/compiler/lib/src/cps_ir...
pkg/compiler/lib/src/cps_ir/cps_ir_builder.dart:2022: addPrimitive(new
ir.GetMutableVariable(mutableVariable)));
I don't really like the side effecting expression as an argument.  I think I'd
rather have:

ir.Primitive get = addPrimitive(new ir.GetMutableVariable(mutableVariable);
environment.update(loopVariable, get);

https://codereview.chromium.org/1010423002/diff/1/pkg/compiler/lib/src/cps_ir...
pkg/compiler/lib/src/cps_ir/cps_ir_builder.dart:2154: environment.extend(local,
Likewise here, name the side-effecting subexpression.

https://codereview.chromium.org/1010423002/diff/1/pkg/compiler/lib/src/cps_ir...
pkg/compiler/lib/src/cps_ir/cps_ir_builder.dart:2301: addPrimitive(new
ir.GetField(box, location.field))));
And here!

[karlklose, 2015-03-19 12:07:05]

Committed patchset #2 (id:20001) manually as 44571 (presubmit successful).