Revert "Optimizations to IC stub for unoptimized code performance on x64."

runtime/vm/assembler_ia32.cc

Index: runtime/vm/assembler_ia32.cc
diff --git a/runtime/vm/assembler_ia32.cc b/runtime/vm/assembler_ia32.cc
index 04d8aeaeb19f4562b7bd14cbcb37afc6552fd74f..713365db6367d1067a1442869329a423cb0f3bee 100644
--- a/runtime/vm/assembler_ia32.cc
+++ b/runtime/vm/assembler_ia32.cc
@@ -2903,54 +2903,26 @@ void Assembler::SmiUntagOrCheckClass(Register object,
 
 
 void Assembler::LoadClassIdMayBeSmi(Register result, Register object) {
-  if (result == object) {
-    Label smi, join;
+  ASSERT(result != object);
+  static const intptr_t kSmiCidSource = kSmiCid << RawObject::kClassIdTagPos;
 
-    testl(object, Immediate(kSmiTagMask));
-    j(EQUAL, &smi, Assembler::kNearJump);
-    LoadClassId(result, object);
-    jmp(&join, Assembler::kNearJump);
+  // Make a dummy "Object" whose cid is kSmiCid.
+  movl(result, Immediate(reinterpret_cast<int32_t>(&kSmiCidSource) + 1));
 
-    Bind(&smi);
-    movl(result, Immediate(kSmiCid));
+  // Check if object (in tmp) is a Smi.
+  testl(object, Immediate(kSmiTagMask));
 
-    Bind(&join);
-  } else {
-    ASSERT(result != object);
-    static const intptr_t kSmiCidSource = kSmiCid << RawObject::kClassIdTagPos;
-
-    // Make a dummy "Object" whose cid is kSmiCid.
-    movl(result, Immediate(reinterpret_cast<int32_t>(&kSmiCidSource) + 1));
-
-    // Check if object (in tmp) is a Smi.
-    testl(object, Immediate(kSmiTagMask));
-
-    // If the object is not a Smi, use the original object to load the cid.
-    // Otherwise, the dummy object is used, and the result is kSmiCid.
-    cmovne(result, object);
-    LoadClassId(result, result);
-  }
+  // If the object is not a Smi, use the original object to load the cid.
+  // Otherwise, the dummy object is used, and the result is kSmiCid.
+  cmovne(result, object);
+  LoadClassId(result, result);
 }
 
 
 void Assembler::LoadTaggedClassIdMayBeSmi(Register result, Register object) {
-  if (result == object) {
-    Label smi, join;
-
-    testl(object, Immediate(kSmiTagMask));
-    j(EQUAL, &smi, Assembler::kNearJump);
-    LoadClassId(result, object);
-    SmiTag(result);
-    jmp(&join, Assembler::kNearJump);
-
-    Bind(&smi);
-    movl(result, Immediate(Smi::RawValue(kSmiCid)));
-
-    Bind(&join);
-  } else {
-    LoadClassIdMayBeSmi(result, object);
-    SmiTag(result);
-  }
+  LoadClassIdMayBeSmi(result, object);
+  // Tag the result.
+  SmiTag(result);
 }