Revert "Compiler changes for bitstring based type checks."

Bug: 64692057
Bug: 71853552
Bug: 26687569

This reverts commit eb0ebed72432b3c6b8c7b38f8937d7ba736f4567.

Change-Id: I7daeaa077960ba41b2ed42bc47f17501621be4be
diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index e85f900..cbe9e0a 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -6234,27 +6234,6 @@
   // No need for memory fence, thanks to the X86 memory model.
 }
 
-void InstructionCodeGeneratorX86::GenerateBitstringTypeCheckCompare(HTypeCheckInstruction* check,
-                                                                    Register temp) {
-  uint32_t path_to_root = check->GetBitstringPathToRoot();
-  uint32_t mask = check->GetBitstringMask();
-  DCHECK(IsPowerOfTwo(mask + 1));
-  size_t mask_bits = WhichPowerOf2(mask + 1);
-
-  if ((false) && mask_bits == 16u) {
-    // FIXME: cmpw() erroneously emits the constant as 32 bits instead of 16 bits. b/71853552
-    // Compare the bitstring in memory.
-    __ cmpw(Address(temp, mirror::Class::StatusOffset()), Immediate(path_to_root));
-  } else {
-    // /* uint32_t */ temp = temp->status_
-    __ movl(temp, Address(temp, mirror::Class::StatusOffset()));
-    // Compare the bitstring bits using SUB.
-    __ subl(temp, Immediate(path_to_root));
-    // Shift out bits that do not contribute to the comparison.
-    __ shll(temp, Immediate(32u - mask_bits));
-  }
-}
-
 HLoadString::LoadKind CodeGeneratorX86::GetSupportedLoadStringKind(
     HLoadString::LoadKind desired_string_load_kind) {
   switch (desired_string_load_kind) {
@@ -6447,8 +6426,6 @@
     case TypeCheckKind::kInterfaceCheck:
       call_kind = LocationSummary::kCallOnSlowPath;
       break;
-    case TypeCheckKind::kBitstringCheck:
-      break;
   }
 
   LocationSummary* locations =
@@ -6457,13 +6434,7 @@
     locations->SetCustomSlowPathCallerSaves(RegisterSet::Empty());  // No caller-save registers.
   }
   locations->SetInAt(0, Location::RequiresRegister());
-  if (type_check_kind == TypeCheckKind::kBitstringCheck) {
-    locations->SetInAt(1, Location::ConstantLocation(instruction->InputAt(1)->AsConstant()));
-    locations->SetInAt(2, Location::ConstantLocation(instruction->InputAt(2)->AsConstant()));
-    locations->SetInAt(3, Location::ConstantLocation(instruction->InputAt(3)->AsConstant()));
-  } else {
-    locations->SetInAt(1, Location::Any());
-  }
+  locations->SetInAt(1, Location::Any());
   // Note that TypeCheckSlowPathX86 uses this "out" register too.
   locations->SetOut(Location::RequiresRegister());
   // When read barriers are enabled, we need a temporary register for some cases.
@@ -6684,21 +6655,6 @@
       }
       break;
     }
-
-    case TypeCheckKind::kBitstringCheck: {
-      // /* HeapReference<Class> */ temp = obj->klass_
-      GenerateReferenceLoadTwoRegisters(instruction,
-                                        out_loc,
-                                        obj_loc,
-                                        class_offset,
-                                        kWithoutReadBarrier);
-
-      GenerateBitstringTypeCheckCompare(instruction, out);
-      __ j(kNotEqual, &zero);
-      __ movl(out, Immediate(1));
-      __ jmp(&done);
-      break;
-    }
   }
 
   if (zero.IsLinked()) {
@@ -6725,10 +6681,6 @@
     // Require a register for the interface check since there is a loop that compares the class to
     // a memory address.
     locations->SetInAt(1, Location::RequiresRegister());
-  } else if (type_check_kind == TypeCheckKind::kBitstringCheck) {
-    locations->SetInAt(1, Location::ConstantLocation(instruction->InputAt(1)->AsConstant()));
-    locations->SetInAt(2, Location::ConstantLocation(instruction->InputAt(2)->AsConstant()));
-    locations->SetInAt(3, Location::ConstantLocation(instruction->InputAt(3)->AsConstant()));
   } else {
     locations->SetInAt(1, Location::Any());
   }
@@ -6948,19 +6900,6 @@
       __ MaybeUnpoisonHeapReference(cls.AsRegister<Register>());
       break;
     }
-
-    case TypeCheckKind::kBitstringCheck: {
-      // /* HeapReference<Class> */ temp = obj->klass_
-      GenerateReferenceLoadTwoRegisters(instruction,
-                                        temp_loc,
-                                        obj_loc,
-                                        class_offset,
-                                        kWithoutReadBarrier);
-
-      GenerateBitstringTypeCheckCompare(instruction, temp);
-      __ j(kNotEqual, type_check_slow_path->GetEntryLabel());
-      break;
-    }
   }
   __ Bind(&done);