Dart VM: Simplify code generation for equality operators.

runtime/vm/intermediate_language_ia32.cc

Index: runtime/vm/intermediate_language_ia32.cc
===================================================================
--- runtime/vm/intermediate_language_ia32.cc	(revision 28079)
+++ runtime/vm/intermediate_language_ia32.cc	(working copy)
@@ -310,14 +310,6 @@
   const Array& kNoArgumentNames = Object::null_array();
   const int kNumArgumentsChecked = 2;
 
-  const Immediate& raw_null =
-      Immediate(reinterpret_cast<intptr_t>(Object::null()));
-  Label check_identity;
-  __ cmpl(Address(ESP, 0 * kWordSize), raw_null);
-  __ j(EQUAL, &check_identity);
-  __ cmpl(Address(ESP, 1 * kWordSize), raw_null);
-  __ j(EQUAL, &check_identity);
-
   ICData& equality_ic_data = ICData::ZoneHandle();
   if (compiler->is_optimizing() && FLAG_propagate_ic_data) {
     ASSERT(!original_ic_data.IsNull());
@@ -344,39 +336,6 @@
                                  kNoArgumentNames,
                                  locs,
                                  equality_ic_data);
-  Label check_ne;
-  __ jmp(&check_ne);
-
-  __ Bind(&check_identity);
-  Label equality_done;
-  if (compiler->is_optimizing()) {
-    // No need to update IC data.
-    Label is_true;
-    __ popl(EAX);
-    __ popl(EDX);
-    __ cmpl(EAX, EDX);
-    __ j(EQUAL, &is_true);
-    __ LoadObject(EAX, Bool::Get(kind != Token::kEQ));
-    __ jmp(&equality_done);
-    __ Bind(&is_true);
-    __ LoadObject(EAX, Bool::Get(kind == Token::kEQ));
-    if (kind == Token::kNE) {
-      // Skip not-equal result conversion.
-      __ jmp(&equality_done);
-    }
-  } else {
-    // Call stub, load IC data in register. The stub will update ICData if
-    // necessary.
-    Register ic_data_reg = locs->temp(0).reg();
-    ASSERT(ic_data_reg == ECX);  // Stub depends on it.
-    __ LoadObject(ic_data_reg, equality_ic_data);
-    compiler->GenerateCall(token_pos,
-                           &StubCode::EqualityWithNullArgLabel(),
-                           PcDescriptors::kRuntimeCall,
-                           locs);
-    __ Drop(2);
-  }
-  __ Bind(&check_ne);
   if (kind == Token::kNE) {
     Label true_label, done;
     // Negate the condition: true label returns false and vice versa.
@@ -388,7 +347,6 @@
     __ LoadObject(EAX, Bool::False());
     __ Bind(&done);
   }
-  __ Bind(&equality_done);
 }
 
 
@@ -562,35 +520,10 @@
   ASSERT(!ic_data.IsNull() && (ic_data.NumberOfChecks() > 0));
   Register left = locs->in(0).reg();
   Register right = locs->in(1).reg();
-  const Immediate& raw_null =
-      Immediate(reinterpret_cast<intptr_t>(Object::null()));
-  Label done, identity_compare, non_null_compare;
-  __ cmpl(right, raw_null);
-  __ j(EQUAL, &identity_compare, Assembler::kNearJump);
-  __ cmpl(left, raw_null);
-  __ j(NOT_EQUAL, &non_null_compare, Assembler::kNearJump);
-  // Comparison with NULL is "===".
-  __ Bind(&identity_compare);
-  __ cmpl(left, right);
-  Condition cond = TokenKindToSmiCondition(kind);
-  if (branch != NULL) {
-    branch->EmitBranchOnCondition(compiler, cond);
-  } else {
-    Register result = locs->out().reg();
-    Label load_true;
-    __ j(cond, &load_true, Assembler::kNearJump);
-    __ LoadObject(result, Bool::False());
-    __ jmp(&done);
-    __ Bind(&load_true);
-    __ LoadObject(result, Bool::True());
-  }
-  __ jmp(&done);
-  __ Bind(&non_null_compare);  // Receiver is not null.
   __ pushl(left);
   __ pushl(right);
   EmitEqualityAsPolymorphicCall(compiler, ic_data, locs, branch, kind,
                                 deopt_id, token_pos);
-  __ Bind(&done);
 }