Refactor HCheckInstanceType to allow mask/tag tests.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 887282b2eb20278d74be7ffc801049836778e10e..f26db274575686f9c9ea81d9e19ebacd1e6bd6ed 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -3650,30 +3650,45 @@ void LCodeGen::DoCheckNonSmi(LCheckNonSmi* instr) {
 
 void LCodeGen::DoCheckInstanceType(LCheckInstanceType* instr) {
   Register input = ToRegister(instr->InputAt(0));
-  InstanceType first = instr->hydrogen()->first();
-  InstanceType last = instr->hydrogen()->last();
 
   __ movq(kScratchRegister, FieldOperand(input, HeapObject::kMapOffset));
 
-  // If there is only one type in the interval check for equality.
-  if (first == last) {
+  if (instr->hydrogen()->is_interval_check()) {
+    InstanceType first;
+    InstanceType last;
+    instr->hydrogen()->GetCheckInterval(&first, &last);
+
     __ cmpb(FieldOperand(kScratchRegister, Map::kInstanceTypeOffset),
             Immediate(static_cast<int8_t>(first)));
-    DeoptimizeIf(not_equal, instr->environment());
-  } else if (first == FIRST_STRING_TYPE && last == LAST_STRING_TYPE) {
-    // String has a dedicated bit in instance type.
-    __ testb(FieldOperand(kScratchRegister, Map::kInstanceTypeOffset),
-             Immediate(kIsNotStringMask));
-    DeoptimizeIf(not_zero, instr->environment());
+
+    // If there is only one type in the interval check for equality.
+    if (first == last) {
+      DeoptimizeIf(not_equal, instr->environment());
+    } else {
+      DeoptimizeIf(below, instr->environment());
+      // Omit check for the last type.
+      if (last != LAST_TYPE) {
+        __ cmpb(FieldOperand(kScratchRegister, Map::kInstanceTypeOffset),
+                Immediate(static_cast<int8_t>(last)));
+        DeoptimizeIf(above, instr->environment());
+      }
+    }
   } else {
-    __ cmpb(FieldOperand(kScratchRegister, Map::kInstanceTypeOffset),
-            Immediate(static_cast<int8_t>(first)));
-    DeoptimizeIf(below, instr->environment());
-    // Omit check for the last type.
-    if (last != LAST_TYPE) {
-      __ cmpb(FieldOperand(kScratchRegister, Map::kInstanceTypeOffset),
-              Immediate(static_cast<int8_t>(last)));
-      DeoptimizeIf(above, instr->environment());
+    uint8_t mask;
+    uint8_t tag;
+    instr->hydrogen()->GetCheckMaskAndTag(&mask, &tag);
+
+    if (IsPowerOf2(mask)) {
+      ASSERT(tag == 0 || IsPowerOf2(tag));
+      __ testb(FieldOperand(kScratchRegister, Map::kInstanceTypeOffset),
+               Immediate(mask));
+      DeoptimizeIf(tag == 0 ? not_zero : zero, instr->environment());
+    } else {
+      __ movzxbl(kScratchRegister,
+                 FieldOperand(kScratchRegister, Map::kInstanceTypeOffset));
+      __ andb(kScratchRegister, Immediate(mask));
+      __ cmpb(kScratchRegister, Immediate(tag));
+      DeoptimizeIf(not_equal, instr->environment());
     }
   }
 }