dart2js cps: Fix a couple of minor issues.

dart2js cps: Fix a couple of minor issues.

BUG=
R=kmillikin@google.com

Committed: https://github.com/dart-lang/sdk/commit/009cc956d11c7ad9c099848f80157ce25e265abf

[asgerf, 2015-06-29 14:09:11]

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

[asgerf, 2015-06-29 14:09:12]

https://codereview.chromium.org/1212663004/diff/1/pkg/compiler/lib/src/cps_ir...
File pkg/compiler/lib/src/cps_ir/cps_ir_nodes.dart (right):

https://codereview.chromium.org/1212663004/diff/1/pkg/compiler/lib/src/cps_ir...
pkg/compiler/lib/src/cps_ir/cps_ir_nodes.dart:292: bool receiverIsNotNull =
false;
The tree builder expects this to be set, but it's nice to be able to run without
optimizations enabled.

https://codereview.chromium.org/1212663004/diff/1/pkg/compiler/lib/src/tree_i...
File pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart (right):

https://codereview.chromium.org/1212663004/diff/1/pkg/compiler/lib/src/tree_i...
pkg/compiler/lib/src/tree_ir/optimization/statement_rewriter.dart:310: if
(assign.variable.readCount == 1) {
This matters when there is a dead variable due to optimizations being disabled.

https://codereview.chromium.org/1212663004/diff/1/pkg/compiler/lib/src/tree_i...
File pkg/compiler/lib/src/tree_ir/tree_ir_builder.dart (right):

https://codereview.chromium.org/1212663004/diff/1/pkg/compiler/lib/src/tree_i...
pkg/compiler/lib/src/tree_ir/tree_ir_builder.dart:323: if
(continuation.hasMultipleUses || continuation.isRecursive) {
If the continuation is marked as recursive, but all of its recursive invocations
have been eliminated, we still need the label because we translate it into a
while. This is sort of bad, but it's no reason to crash the compiler.

[Kevin Millikin (Google), 2015-06-29 14:43:28]

lgtm

https://codereview.chromium.org/1212663004/diff/1/pkg/compiler/lib/src/tree_i...
File pkg/compiler/lib/src/tree_ir/tree_ir_builder.dart (right):

https://codereview.chromium.org/1212663004/diff/1/pkg/compiler/lib/src/tree_i...
pkg/compiler/lib/src/tree_ir/tree_ir_builder.dart:323: if
(continuation.hasMultipleUses || continuation.isRecursive) {
On 2015/06/29 14:09:12, asgerf wrote:
> If the continuation is marked as recursive, but all of its recursive
invocations
> have been eliminated, we still need the label because we translate it into a
> while. This is sort of bad, but it's no reason to crash the compiler.

The way we do it now has always seemed brittle; we should have something better.
 But I agree we should not crash and this is a simple change to avoid that.

[Kevin Millikin (Google), 2015-06-29 14:43:29]

lgtm

[asgerf, 2015-06-29 14:45:03]

Committed patchset #1 (id:1) manually as
009cc956d11c7ad9c099848f80157ce25e265abf (presubmit successful).