Simplify and optimize ToBoolean handling.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
===================================================================
--- src/x64/lithium-codegen-x64.cc	(revision 8868)
+++ src/x64/lithium-codegen-x64.cc	(working copy)
@@ -1410,40 +1410,19 @@
         // undefined -> false.
         __ CompareRoot(reg, Heap::kUndefinedValueRootIndex);
         __ j(equal, false_label);
-      } else if (expected.Contains(ToBooleanStub::INTERNAL_OBJECT)) {
-        // We've seen undefined for the first time -> deopt.
-        __ CompareRoot(reg, Heap::kUndefinedValueRootIndex);
-        DeoptimizeIf(equal, instr->environment());
       }
-
       if (expected.Contains(ToBooleanStub::BOOLEAN)) {
         // true -> true.
         __ CompareRoot(reg, Heap::kTrueValueRootIndex);
         __ j(equal, true_label);
-      } else if (expected.Contains(ToBooleanStub::INTERNAL_OBJECT)) {
-        // We've seen a boolean for the first time -> deopt.
-        __ CompareRoot(reg, Heap::kTrueValueRootIndex);
-        DeoptimizeIf(equal, instr->environment());
-      }
-
-      if (expected.Contains(ToBooleanStub::BOOLEAN)) {
         // false -> false.
         __ CompareRoot(reg, Heap::kFalseValueRootIndex);
         __ j(equal, false_label);
-      } else if (expected.Contains(ToBooleanStub::INTERNAL_OBJECT)) {
-        // We've seen a boolean for the first time -> deopt.
-        __ CompareRoot(reg, Heap::kFalseValueRootIndex);
-        DeoptimizeIf(equal, instr->environment());
       }
-
       if (expected.Contains(ToBooleanStub::NULL_TYPE)) {
         // 'null' -> false.
         __ CompareRoot(reg, Heap::kNullValueRootIndex);
         __ j(equal, false_label);
-      } else if (expected.Contains(ToBooleanStub::INTERNAL_OBJECT)) {
-        // We've seen null for the first time -> deopt.
-        __ CompareRoot(reg, Heap::kNullValueRootIndex);
-        DeoptimizeIf(equal, instr->environment());
       }
 
       if (expected.Contains(ToBooleanStub::SMI)) {
@@ -1460,21 +1439,19 @@
       const Register map = kScratchRegister;
       if (expected.NeedsMap()) {
         __ movq(map, FieldOperand(reg, HeapObject::kMapOffset));
-        // Everything with a map could be undetectable, so check this now.
-        __ testb(FieldOperand(map, Map::kBitFieldOffset),
-                 Immediate(1 << Map::kIsUndetectable));
-        // Undetectable -> false.
-        __ j(not_zero, false_label);
+
+        if (expected.CanBeUndetectable()) {
+          // Undetectable -> false.
+          __ testb(FieldOperand(map, Map::kBitFieldOffset),
+                   Immediate(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)) {
@@ -1486,10 +1463,6 @@
         __ 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)) {
@@ -1502,19 +1475,10 @@
         __ 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.
-        __ CompareRoot(map, Heap::kHeapNumberMapRootIndex);
-        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());
     }
   }
 }