Remove HIsNilAndBranch (it's now unused)

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 7089c762242e5b500a65722944f5c161a28bda27..33cfd011af44a9a469285e5b9377b6c2ba96f7e2 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -2317,46 +2317,6 @@ void LCodeGen::DoCmpConstantEqAndBranch(LCmpConstantEqAndBranch* instr) {
 }
 
 
-void LCodeGen::DoIsNilAndBranch(LIsNilAndBranch* instr) {
-  Register reg = ToRegister(instr->value());
-  int false_block = chunk_->LookupDestination(instr->false_block_id());
-
-  // If the expression is known to be untagged or a smi, then it's definitely
-  // not null, and it can't be a an undetectable object.
-  if (instr->hydrogen()->representation().IsSpecialization() ||
-      instr->hydrogen()->type().IsSmi()) {
-    EmitGoto(false_block);
-    return;
-  }
-
-  int true_block = chunk_->LookupDestination(instr->true_block_id());
-  Handle<Object> nil_value = instr->nil() == kNullValue ?
-      factory()->null_value() :
-      factory()->undefined_value();
-  __ cmp(reg, nil_value);
-  if (instr->kind() == kStrictEquality) {
-    EmitBranch(true_block, false_block, equal);
-  } else {
-    Handle<Object> other_nil_value = instr->nil() == kNullValue ?
-        factory()->undefined_value() :
-        factory()->null_value();
-    Label* true_label = chunk_->GetAssemblyLabel(true_block);
-    Label* false_label = chunk_->GetAssemblyLabel(false_block);
-    __ j(equal, true_label);
-    __ cmp(reg, other_nil_value);
-    __ j(equal, true_label);
-    __ JumpIfSmi(reg, false_label);
-    // Check for undetectable objects by looking in the bit field in
-    // the map. The object has already been smi checked.
-    Register scratch = ToRegister(instr->temp());
-    __ mov(scratch, FieldOperand(reg, HeapObject::kMapOffset));
-    __ movzx_b(scratch, FieldOperand(scratch, Map::kBitFieldOffset));
-    __ test(scratch, Immediate(1 << Map::kIsUndetectable));
-    EmitBranch(true_block, false_block, not_zero);
-  }
-}
-
-
 Condition LCodeGen::EmitIsObject(Register input,
                                  Register temp1,
                                  Label* is_not_object,