Improve and simplify removal of unreachable code

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index b3158685fcf40e3e60d7088b8af06e9e39fa0775..ac693121fa0393bc67529f4ea29fe1b02d54bae1 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -1048,10 +1048,8 @@ LInstruction* LChunkBuilder::DoBranch(HBranch* instr) {
   if (value->EmitAtUses()) {
     ASSERT(value->IsConstant());
     ASSERT(!value->representation().IsDouble());
-    HBasicBlock* successor = HConstant::cast(value)->BooleanValue()
-        ? instr->FirstSuccessor()
-        : instr->SecondSuccessor();
-    return new(zone()) LGoto(successor->block_id());
+    return ElideControlInstruction(instr,
+                                   HConstant::cast(value)->BooleanValue());
   }
 
   ToBooleanStub::Types expected = instr->expected_input_types();
@@ -1737,6 +1735,13 @@ LInstruction* LChunkBuilder::DoCompareNumericAndBranch(
 
 LInstruction* LChunkBuilder::DoCompareObjectEqAndBranch(
     HCompareObjectEqAndBranch* instr) {
+  if (instr->left()->IsConstant() && instr->right()->IsConstant()) {
+    bool comparison_result =
+        HConstant::cast(instr->left())->SameConstantObject(
+            HConstant::cast(instr->right()));
+    return ElideControlInstruction(instr, comparison_result);
+  }
+
   LOperand* left = UseRegisterAtStart(instr->left());
   LOperand* right = UseOrConstantAtStart(instr->right());
   return new(zone()) LCmpObjectEqAndBranch(left, right);