Use range information to omit checks in TRUNCDIV/MOD operations.

Use range information to omit checks in TRUNCDIV/MOD operations.

R=fschneider@google.com

Committed: https://code.google.com/p/dart/source/detail?r=30673

[Florian Schneider, 2013-11-22 15:17:10]

https://codereview.chromium.org/81623003/diff/60001/runtime/vm/intermediate_l...
File runtime/vm/intermediate_language_ia32.cc (right):

https://codereview.chromium.org/81623003/diff/60001/runtime/vm/intermediate_l...
runtime/vm/intermediate_language_ia32.cc:2457: if ((right_range == NULL) ||
right_range->IsWithin(0, 0)) {
Please also make sure that there is test coverage of all the cases. What if
right_range is [-5, 5]?
In this case you need a check, but [-5, 5]->IsWithin(0, 0) would return false
and the check would be omitted.

https://codereview.chromium.org/81623003/diff/60001/runtime/vm/intermediate_l...
runtime/vm/intermediate_language_ia32.cc:2482: }
In the case that the instruction can't deoptimize because of div-by-zero
anymore, you should return false for CanDeoptimize() to avoid having unnessesary
environment uses.

[srdjan, 2013-11-22 22:08:16]

https://codereview.chromium.org/81623003/diff/60001/runtime/vm/intermediate_l...
File runtime/vm/intermediate_language_ia32.cc (right):

https://codereview.chromium.org/81623003/diff/60001/runtime/vm/intermediate_l...
runtime/vm/intermediate_language_ia32.cc:2457: if ((right_range == NULL) ||
right_range->IsWithin(0, 0)) {
On 2013/11/22 15:17:11, Florian Schneider wrote:
> Please also make sure that there is test coverage of all the cases. What if
> right_range is [-5, 5]?
> In this case you need a check, but [-5, 5]->IsWithin(0, 0) would return false
> and the check would be omitted.

Added test coverage, added Range::Overlaps function.

https://codereview.chromium.org/81623003/diff/60001/runtime/vm/intermediate_l...
runtime/vm/intermediate_language_ia32.cc:2482: }
On 2013/11/22 15:17:11, Florian Schneider wrote:
> In the case that the instruction can't deoptimize because of div-by-zero
> anymore, you should return false for CanDeoptimize() to avoid having
unnessesary
> environment uses.

Changed BinarySmiOperation::CanDeoptimize.

[Florian Schneider, 2013-11-26 10:52:01]

LGTM.

[srdjan, 2013-11-26 18:18:34]

Committed patchset #6 manually as r30673 (presubmit successful).