Revert of Version 5.0.71.10 (cherry-pick)

src/mips/code-stubs-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_MIPS
 
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 700 matching lines @@
                       a3);
   if (cc == eq) {
     StringHelper::GenerateFlatOneByteStringEquals(masm, lhs, rhs, a2, a3, t0);
   } else {
     StringHelper::GenerateCompareFlatOneByteStrings(masm, lhs, rhs, a2, a3, t0,
                                                     t1);
   }
   // Never falls through to here.
 
   __ bind(&slow);
+  // Prepare for call to builtin. Push object pointers, a0 (lhs) first,
+  // a1 (rhs) second.
+  __ Push(lhs, rhs);
+  // Figure out which native to call and setup the arguments.
   if (cc == eq) {
-    {
-      FrameScope scope(masm, StackFrame::INTERNAL);
-      __ Push(lhs, rhs);
-      __ CallRuntime(strict() ? Runtime::kStrictEqual : Runtime::kEqual);
-    }
-    // Turn true into 0 and false into some non-zero value.
-    STATIC_ASSERT(EQUAL == 0);
-    __ LoadRoot(a0, Heap::kTrueValueRootIndex);
-    __ Ret(USE_DELAY_SLOT);
-    __ subu(v0, v0, a0);  // In delay slot.
+    __ TailCallRuntime(strict() ? Runtime::kStrictEquals : Runtime::kEquals);
   } else {
-    // Prepare for call to builtin. Push object pointers, a0 (lhs) first,
-    // a1 (rhs) second.
-    __ Push(lhs, rhs);
     int ncr;  // NaN compare result.
     if (cc == lt || cc == le) {
       ncr = GREATER;
     } else {
       DCHECK(cc == gt || cc == ge);  // Remaining cases.
       ncr = LESS;
     }
     __ li(a0, Operand(Smi::FromInt(ncr)));
     __ push(a0);
 
@@ skipping 5049 matching lines @@
                            return_value_operand, NULL);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS