Better value range propagation by supporting negating ranges.

Better value range propagation by supporting negating ranges.
Committed: https://code.google.com/p/dart/source/detail?r=13358

[Søren Gjesse, 2012-10-08 14:00:42]

lgtm

https://codereview.chromium.org/11066053/diff/2001/lib/compiler/implementatio...
File lib/compiler/implementation/ssa/value_range_analyzer.dart (right):

https://codereview.chromium.org/11066053/diff/2001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/value_range_analyzer.dart:14: Value operator
-(Value other);
Don't you want to add unary minus here as well?

https://codereview.chromium.org/11066053/diff/2001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/value_range_analyzer.dart:245: Value operator
-() => -left - right;
Maybe -(left + right) instead.

https://codereview.chromium.org/11066053/diff/2001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/value_range_analyzer.dart:323: bool isNegative()
=> false;
Isn't this negative if left is negative and right is positive - or am I missing
something here?

https://codereview.chromium.org/11066053/diff/2001/tests/compiler/dart2js/val...
File tests/compiler/dart2js/value_range2_test.dart (right):

https://codereview.chromium.org/11066053/diff/2001/tests/compiler/dart2js/val...
tests/compiler/dart2js/value_range2_test.dart:47: // Create a bound just like
the algorithm does.
Which algorithm? (add more context to the reference).

[ngeoffray, 2012-10-08 14:16:39]

Thanks Soren

https://codereview.chromium.org/11066053/diff/2001/lib/compiler/implementatio...
File lib/compiler/implementation/ssa/value_range_analyzer.dart (right):

https://codereview.chromium.org/11066053/diff/2001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/value_range_analyzer.dart:14: Value operator
-(Value other);
On 2012/10/08 14:00:42, Søren Gjesse wrote:
> Don't you want to add unary minus here as well?

Yes. Done.

https://codereview.chromium.org/11066053/diff/2001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/value_range_analyzer.dart:245: Value operator
-() => -left - right;
On 2012/10/08 14:00:42, Søren Gjesse wrote:
> Maybe -(left + right) instead.

Calling -(left + right) will actually yield -left - right, after a few more
indirections. I'd rather not play with parenthesized expressions just yet :)

https://codereview.chromium.org/11066053/diff/2001/lib/compiler/implementatio...
lib/compiler/implementation/ssa/value_range_analyzer.dart:323: bool isNegative()
=> false;
On 2012/10/08 14:00:42, Søren Gjesse wrote:
> Isn't this negative if left is negative and right is positive - or am I
missing
> something here?

You're right. Done.

https://codereview.chromium.org/11066053/diff/2001/tests/compiler/dart2js/val...
File tests/compiler/dart2js/value_range2_test.dart (right):

https://codereview.chromium.org/11066053/diff/2001/tests/compiler/dart2js/val...
tests/compiler/dart2js/value_range2_test.dart:47: // Create a bound just like
the algorithm does.
On 2012/10/08 14:00:42, Søren Gjesse wrote:
> Which algorithm? (add more context to the reference).

Done.