Fix HTypeConversion.checkedInput

Fix HTypeConversion.checkedInput

For function types, HTypeConversion.checkedInput would return the call
to the method on the reified type object.  Now the construction of the
call is deferred to codegen.dart, so the input is available directly.

The optimizer also detects checks (type assertions and 'as' casts) on
`null` values and removes the useless test.

BUG=
R=efortuna@google.com

Committed: https://github.com/dart-lang/sdk/commit/4bd5671a31fa4a3d70716ff137092b46b4a59e22

[sra1, 2016-11-15 01:55:56]

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

[Emily Fortuna, 2016-11-15 17:52:39]

lgtm

https://codereview.chromium.org/2497313003/diff/20001/pkg/compiler/lib/src/ss...
File pkg/compiler/lib/src/ssa/optimize.dart (right):

https://codereview.chromium.org/2497313003/diff/20001/pkg/compiler/lib/src/ss...
pkg/compiler/lib/src/ssa/optimize.dart:808: if (input.isNull()) return input;
Might add a little comment about the logic here. I initially thought this might
be a logic-switch up until I read your top level CL comment.

[sra1, 2016-11-15 18:25:58]

https://codereview.chromium.org/2497313003/diff/20001/pkg/compiler/lib/src/ss...
File pkg/compiler/lib/src/ssa/optimize.dart (right):

https://codereview.chromium.org/2497313003/diff/20001/pkg/compiler/lib/src/ss...
pkg/compiler/lib/src/ssa/optimize.dart:808: if (input.isNull()) return input;
On 2016/11/15 17:52:39, Emily Fortuna wrote:
> Might add a little comment about the logic here. I initially thought this
might
> be a logic-switch up until I read your top level CL comment.

Done.

[sra1, 2016-11-15 23:52:09]

Description was changed from

==========
Fix HTypeConversion.checkedInput

For function types, HTypeConversion.checkedInput would return the call
to the method on the reified type object.  Now the construction of the
call is deferred to codegen.dart, so the input is available directly.

The optimizer also detects checks (type assertions and 'as' casts) on
`null` values and removes the useless test.

BUG=
==========

to

==========
Fix HTypeConversion.checkedInput

For function types, HTypeConversion.checkedInput would return the call
to the method on the reified type object.  Now the construction of the
call is deferred to codegen.dart, so the input is available directly.

The optimizer also detects checks (type assertions and 'as' casts) on
`null` values and removes the useless test.

BUG=
R=efortuna@google.com

Committed:
https://github.com/dart-lang/sdk/commit/4bd5671a31fa4a3d70716ff137092b46b4a59e22
==========

[sra1, 2016-11-15 23:52:11]

Committed patchset #3 (id:40001) manually as
4bd5671a31fa4a3d70716ff137092b46b4a59e22 (presubmit successful).