Simplify and optimize ToBoolean handling.

src/ia32/lithium-codegen-ia32.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1394 matching lines @@
       Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
       ToBooleanStub::Types expected = instr->hydrogen()->expected_input_types();
       // Avoid deopts in the case where we've never executed this path before.
       if (expected.IsEmpty()) expected = ToBooleanStub::all_types();
 
       if (expected.Contains(ToBooleanStub::UNDEFINED)) {
         // undefined -> false.
         __ cmp(reg, factory()->undefined_value());
         __ j(equal, false_label);
-      } else if (expected.Contains(ToBooleanStub::INTERNAL_OBJECT)) {
-        // We've seen undefined for the first time -> deopt.
-        __ cmp(reg, factory()->undefined_value());
-        DeoptimizeIf(equal, instr->environment());
       }
-
       if (expected.Contains(ToBooleanStub::BOOLEAN)) {
         // true -> true.
         __ cmp(reg, factory()->true_value());
         __ j(equal, true_label);
-      } else if (expected.Contains(ToBooleanStub::INTERNAL_OBJECT)) {
-        // We've seen a boolean for the first time -> deopt.
-        __ cmp(reg, factory()->true_value());
-        DeoptimizeIf(equal, instr->environment());
-      }
-
-      if (expected.Contains(ToBooleanStub::BOOLEAN)) {
         // false -> false.
         __ cmp(reg, factory()->false_value());
         __ j(equal, false_label);
-      } else if (expected.Contains(ToBooleanStub::INTERNAL_OBJECT)) {
-        // We've seen a boolean for the first time -> deopt.
-        __ cmp(reg, factory()->false_value());
-        DeoptimizeIf(equal, instr->environment());
       }
-
       if (expected.Contains(ToBooleanStub::NULL_TYPE)) {
         // 'null' -> false.
         __ cmp(reg, factory()->null_value());
         __ j(equal, false_label);
-      } else if (expected.Contains(ToBooleanStub::INTERNAL_OBJECT)) {
-        // We've seen null for the first time -> deopt.
-        __ cmp(reg, factory()->null_value());
-        DeoptimizeIf(equal, instr->environment());
       }
 
       if (expected.Contains(ToBooleanStub::SMI)) {
         // Smis: 0 -> false, all other -> true.
         __ test(reg, Operand(reg));
         __ j(equal, false_label);
         __ JumpIfSmi(reg, true_label);
       } else if (expected.NeedsMap()) {
         // If we need a map later and have a Smi -> deopt.
         __ test(reg, Immediate(kSmiTagMask));
         DeoptimizeIf(zero, instr->environment());
       }
 
-      Register map = no_reg;
+      Register map = no_reg;  // Keep the compiler happy.
       if (expected.NeedsMap()) {
         map = ToRegister(instr->TempAt(0));
         ASSERT(!map.is(reg));
         __ mov(map, FieldOperand(reg, HeapObject::kMapOffset));
-        // Everything with a map could be undetectable, so check this now.
-        __ test_b(FieldOperand(map, Map::kBitFieldOffset),
-                  1 << Map::kIsUndetectable);
-        // Undetectable -> false.
-        __ j(not_zero, false_label);
+
+        if (expected.CanBeUndetectable()) {
+          // Undetectable -> false.
+          __ test_b(FieldOperand(map, Map::kBitFieldOffset),
+                    1 << Map::kIsUndetectable);
+          __ j(not_zero, false_label);
+        }
       }
 
       if (expected.Contains(ToBooleanStub::SPEC_OBJECT)) {
         // spec object -> true.
         __ CmpInstanceType(map, FIRST_SPEC_OBJECT_TYPE);
         __ j(above_equal, true_label);
-      } else if (expected.Contains(ToBooleanStub::INTERNAL_OBJECT)) {
-        // We've seen a spec object for the first time -> deopt.
-        __ CmpInstanceType(map, FIRST_SPEC_OBJECT_TYPE);
-        DeoptimizeIf(above_equal, instr->environment());
       }
 
       if (expected.Contains(ToBooleanStub::STRING)) {
         // String value -> false iff empty.
         Label not_string;
         __ CmpInstanceType(map, FIRST_NONSTRING_TYPE);
         __ j(above_equal, &not_string, Label::kNear);
         __ cmp(FieldOperand(reg, String::kLengthOffset), Immediate(0));
         __ j(not_zero, true_label);
         __ jmp(false_label);
         __ bind(&not_string);
-      } else if (expected.Contains(ToBooleanStub::INTERNAL_OBJECT)) {
-        // We've seen a string for the first time -> deopt
-        __ CmpInstanceType(map, FIRST_NONSTRING_TYPE);
-        DeoptimizeIf(below, instr->environment());
       }
 
       if (expected.Contains(ToBooleanStub::HEAP_NUMBER)) {
         // heap number -> false iff +0, -0, or NaN.
         Label not_heap_number;
         __ cmp(FieldOperand(reg, HeapObject::kMapOffset),
                factory()->heap_number_map());
         __ j(not_equal, &not_heap_number, Label::kNear);
         __ fldz();
         __ fld_d(FieldOperand(reg, HeapNumber::kValueOffset));
         __ FCmp();
         __ j(zero, false_label);
         __ jmp(true_label);
         __ bind(&not_heap_number);
-      } else if (expected.Contains(ToBooleanStub::INTERNAL_OBJECT)) {
-        // We've seen a heap number for the first time -> deopt.
-        __ cmp(FieldOperand(reg, HeapObject::kMapOffset),
-               factory()->heap_number_map());
-        DeoptimizeIf(equal, instr->environment());
       }
 
-      if (expected.Contains(ToBooleanStub::INTERNAL_OBJECT)) {
-        // internal objects -> true
-        __ jmp(true_label);
-      } else {
-        // We've seen something for the first time -> deopt.
-        DeoptimizeIf(no_condition, instr->environment());
-      }
+      // We've seen something for the first time -> deopt.
+      DeoptimizeIf(no_condition, instr->environment());
     }
   }
 }
 
 
 void LCodeGen::EmitGoto(int block) {
   block = chunk_->LookupDestination(block);
   int next_block = GetNextEmittedBlock(current_block_);
   if (block != next_block) {
     __ jmp(chunk_->GetAssemblyLabel(block));
@@ skipping 2864 matching lines @@
                                          env->deoptimization_index());
   __ InvokeBuiltin(Builtins::IN, CALL_FUNCTION, safepoint_generator);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32