Implement type recording for ToBoolean on ARM.

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
===================================================================
--- src/arm/lithium-arm.cc	(revision 8836)
+++ src/arm/lithium-arm.cc	(working copy)
@@ -1039,7 +1039,11 @@
         : instr->SecondSuccessor();
     return new LGoto(successor->block_id());
   }
-  return new LBranch(UseRegisterAtStart(v));
+  LInstruction* branch = new LBranch(UseRegister(v));
+  // When we handle all cases, we never deopt, so we don't need to assign the
+  // environment then.

[Erik Corry, 2011/08/05 12:50:46]

Do we hit this case in the tests?

I would guess it is so rare that the best way may be not to special case it.

[Sven Panne, 2011/08/09 07:58:21]

Currently it happens quite often, because we fall back to "handle all" mode when
we haven't seen any type yet. This is done to avoid heavy performance
regressions caused by too many deoptimizations in these cases. So I propose
quite the opposite: Skip AssignEnvironment when the expected_input_types are
empty, too.

Let's reconsider this logic we handle these cases more intelligently.

+  bool all_cases_handled = instr->expected_input_types().IsAll();
+  return all_cases_handled ? branch : AssignEnvironment(branch);
 }