Improve constant propagation for Mint and Smi.

Improve constant propagation for Mint and Smi.

R=kmillikin@google.com

Committed: https://code.google.com/p/dart/source/detail?r=23020

[Kevin Millikin (Google), 2013-05-22 07:50:35]

LGTM.

https://codereview.chromium.org/15507006/diff/5001/runtime/vm/flow_graph_opti...
File runtime/vm/flow_graph_optimizer.cc (right):

https://codereview.chromium.org/15507006/diff/5001/runtime/vm/flow_graph_opti...
runtime/vm/flow_graph_optimizer.cc:5348: SetValue(instr, non_constant_);
I think this is where we would support arithmetic simplifications.  Maybe add a
TODO to consider adding and subtracting 0, multiplication or division by 1,
multiplication by 0, etc.

https://codereview.chromium.org/15507006/diff/5001/runtime/vm/flow_graph_opti...
runtime/vm/flow_graph_optimizer.cc:5366: case Token::kSHR: {
I'm not sure about the official VM style, but I usually leave these braces off
when there are no declarations in the scope.

https://codereview.chromium.org/15507006/diff/5001/runtime/vm/flow_graph_opti...
runtime/vm/flow_graph_optimizer.cc:5387: // TODO(kmillikin): support other smi
operations.
This comment is a bit out of date now.  I think the only operation not supported
here is Token::kDIV.

Maybe just add a SetValue(instr, non_constant_) case for that an an unreachable
default?

https://codereview.chromium.org/15507006/diff/5001/runtime/vm/intermediate_la...
File runtime/vm/intermediate_language.cc (right):

https://codereview.chromium.org/15507006/diff/5001/runtime/vm/intermediate_la...
runtime/vm/intermediate_language.cc:198: // Check that the value is not an
incorrect Integer presentation.
presentation ==> representation?

[srdjan, 2013-05-22 15:13:33]

https://codereview.chromium.org/15507006/diff/5001/runtime/vm/flow_graph_opti...
File runtime/vm/flow_graph_optimizer.cc (right):

https://codereview.chromium.org/15507006/diff/5001/runtime/vm/flow_graph_opti...
runtime/vm/flow_graph_optimizer.cc:5348: SetValue(instr, non_constant_);
On 2013/05/22 07:50:35, kmillikin wrote:
> I think this is where we would support arithmetic simplifications.  Maybe add
a
> TODO to consider adding and subtracting 0, multiplication or division by 1,
> multiplication by 0, etc.

Added comment:
// TODO(srdjan): Add arithemtic simplifications, e.g, add with 0.

https://codereview.chromium.org/15507006/diff/5001/runtime/vm/flow_graph_opti...
runtime/vm/flow_graph_optimizer.cc:5366: case Token::kSHR: {
On 2013/05/22 07:50:35, kmillikin wrote:
> I'm not sure about the official VM style, but I usually leave these braces off
> when there are no declarations in the scope.

Removed braces.

https://codereview.chromium.org/15507006/diff/5001/runtime/vm/flow_graph_opti...
runtime/vm/flow_graph_optimizer.cc:5387: // TODO(kmillikin): support other smi
operations.
On 2013/05/22 07:50:35, kmillikin wrote:
> This comment is a bit out of date now.  I think the only operation not
supported
> here is Token::kDIV.
> 
> Maybe just add a SetValue(instr, non_constant_) case for that an an
unreachable
> default?

Done.

https://codereview.chromium.org/15507006/diff/5001/runtime/vm/intermediate_la...
File runtime/vm/intermediate_language.cc (right):

https://codereview.chromium.org/15507006/diff/5001/runtime/vm/intermediate_la...
runtime/vm/intermediate_language.cc:198: // Check that the value is not an
incorrect Integer presentation.
On 2013/05/22 07:50:35, kmillikin wrote:
> presentation ==> representation?

Done.

[srdjan, 2013-05-22 15:21:01]

Committed patchset #3 manually as r23020 (presubmit successful).