Enable merging of comparisons into branches in checked mode.

Enable merging of comparisons into branches in checked mode.

Instead of inserting an explicit type check at branches, the
branch instruction checks the input for boolean itself:

"if (a < b)" will be translated by the flowgraph builder
like this:

  CheckedBranch(a < b)

before it would look like this:

  t1 <- (a < b)
  t2 <- AssertBool(t1)
  Branch(t2 === true)


Also in this change:
flow_graph_optimizer.cc contains a small fix of an assert triggered when running with --trace-optimization.
Committed: https://code.google.com/p/dart/source/detail?r=14006

[srdjan, 2012-10-23 18:06:05]

LGTM

https://codereview.chromium.org/11232063/diff/1/runtime/vm/intermediate_langu...
File runtime/vm/intermediate_language.h (right):

https://codereview.chromium.org/11232063/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language.h:1519: bool is_checked_;
const

https://codereview.chromium.org/11232063/diff/1/runtime/vm/intermediate_langu...
File runtime/vm/intermediate_language_ia32.cc (right):

https://codereview.chromium.org/11232063/diff/1/runtime/vm/intermediate_langu...
runtime/vm/intermediate_language_ia32.cc:205: __ j(EQUAL, &done,
Assembler::kNearJump);
Would it be faster to get cid of reg and check if it is Boolean?

[Florian Schneider, 2012-10-24 13:02:09]

https://chromiumcodereview.appspot.com/11232063/diff/1/runtime/vm/intermediat...
File runtime/vm/intermediate_language.h (right):

https://chromiumcodereview.appspot.com/11232063/diff/1/runtime/vm/intermediat...
runtime/vm/intermediate_language.h:1519: bool is_checked_;
On 2012/10/23 18:06:06, srdjan wrote:
> const 

Done.

https://chromiumcodereview.appspot.com/11232063/diff/1/runtime/vm/intermediat...
File runtime/vm/intermediate_language_ia32.cc (right):

https://chromiumcodereview.appspot.com/11232063/diff/1/runtime/vm/intermediat...
runtime/vm/intermediate_language_ia32.cc:205: __ j(EQUAL, &done,
Assembler::kNearJump);
On 2012/10/23 18:06:06, srdjan wrote:
> Would it be faster to get cid of reg and check if it is Boolean?

I have not measured that yet, but I'll do a measurement once this is landed.