Add monomorphic CompareNilICs and Crankshaft support

src/lithium.cc

Index: src/lithium.cc
diff --git a/src/lithium.cc b/src/lithium.cc
index b4a57f520bc8fa464f3d61ecb8262254b71563ee..6d4cb776dd48bad1266f1c011b9aecd5876b790f 100644
--- a/src/lithium.cc
+++ b/src/lithium.cc
@@ -329,7 +329,7 @@ void LChunk::MarkEmptyBlocks() {
             can_eliminate = false;
           }
         }
-
+        if (block->predecessors()->length() > 1) can_eliminate = false;

[mvstanton, 2013/04/23 09:27:30]

What is it unique about this CL that requires this change? Is it use of blocks
for push/pop of environment HValues?

[danno, 2013/04/23 16:14:47]

Removed.

On 2013/04/23 09:27:30, mvstanton wrote:

         if (can_eliminate) {
           label->set_replacement(GetLabel(goto_instr->block_id()));
         }