Fix bad optimization of instance-of with uninstantiated types (issue 5216).

Fix bad optimization of instance-of with uninstantiated types (issue 5216).
Fix bad assert when type check elimination is disabled (issue 5217).
Cleanup of type elimination code in optimizing compiler.
Add test.
Committed: https://code.google.com/p/dart/source/detail?r=12502

[regis, 2012-09-18 06:07:03]

Hello Ian,

Here is your reward for filling these issues :-)
Not really, but since most of my usual reviewers are either in vacation or out
sick, you get the honor.

Thanks,
Regis

[zerny-google, 2012-09-18 11:20:24]

lgtm with a few comments.

https://codereview.chromium.org/10942006/diff/1/runtime/vm/intermediate_langu...
File runtime/vm/intermediate_language.cc (right):

https://codereview.chromium.org/10942006/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language.cc:349: return true;
is_instance does not appear to be set when this returns true.

https://codereview.chromium.org/10942006/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/10942006/diff/1/runtime/vm/object.cc#newcode8542
runtime/vm/object.cc:8542: // compile time. Both sentinels are instances of the
Null class, but they
Can we assert that?

[regis, 2012-09-18 14:55:44]

Thank you, Sir!

https://codereview.chromium.org/10942006/diff/1/runtime/vm/intermediate_langu...
File runtime/vm/intermediate_language.cc (right):

https://codereview.chromium.org/10942006/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language.cc:349: return true;
On 2012/09/18 11:20:24, zerny wrote:
> is_instance does not appear to be set when this returns true.

Good catch!

https://codereview.chromium.org/10942006/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://codereview.chromium.org/10942006/diff/1/runtime/vm/object.cc#newcode8542
runtime/vm/object.cc:8542: // compile time. Both sentinels are instances of the
Null class, but they
On 2012/09/18 11:20:24, zerny wrote:
> Can we assert that?

There is already an assert for !FLAG_eliminate_type_checks. I added one checking
that this instance is indeed one of the  sentinels.