Fixed deopt reasons in TaggedToI.

src/mips64/lithium-codegen-mips64.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.
 
 #include "src/v8.h"
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/hydrogen-osr.h"
 #include "src/ic/ic.h"
@@ skipping 4955 matching lines @@
     __ mov(input_reg, zero_reg);  // In delay slot.
 
     __ bind(&check_bools);
     __ LoadRoot(at, Heap::kTrueValueRootIndex);
     __ Branch(&check_false, ne, scratch2, Operand(at));
     __ Branch(USE_DELAY_SLOT, &done);
     __ li(input_reg, Operand(1));  // In delay slot.
 
     __ bind(&check_false);
     __ LoadRoot(at, Heap::kFalseValueRootIndex);
+    __ RecordComment("Deferred TaggedToI: cannot truncate");
     DeoptimizeIf(ne, instr->environment(), scratch2, Operand(at));
     __ Branch(USE_DELAY_SLOT, &done);
     __ mov(input_reg, zero_reg);  // In delay slot.
   } else {
-    // Deoptimize if we don't have a heap number.
+    __ RecordComment("Deferred TaggedToI: not a heap number");
     DeoptimizeIf(ne, instr->environment(), scratch1, Operand(at));
 
     // Load the double value.
     __ ldc1(double_scratch,
             FieldMemOperand(input_reg, HeapNumber::kValueOffset));
 
     Register except_flag = scratch2;
     __ EmitFPUTruncate(kRoundToZero,
                        input_reg,
                        double_scratch,
                        scratch1,
                        double_scratch2,
                        except_flag,
                        kCheckForInexactConversion);
 
-    // Deopt if the operation did not succeed.
+    __ RecordComment("Deferred TaggedToI: lost precision or NaN");
     DeoptimizeIf(ne, instr->environment(), except_flag, Operand(zero_reg));
 
     if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
       __ Branch(&done, ne, input_reg, Operand(zero_reg));
 
       __ mfhc1(scratch1, double_scratch);  // Get exponent/sign bits.
       __ And(scratch1, scratch1, Operand(HeapNumber::kSignMask));
+      __ RecordComment("Deferred TaggedToI: minus zero");
       DeoptimizeIf(ne, instr->environment(), scratch1, Operand(zero_reg));
     }
   }
   __ bind(&done);
 }
 
 
 void LCodeGen::DoTaggedToI(LTaggedToI* instr) {
   class DeferredTaggedToI FINAL : public LDeferredCode {
    public:
@@ skipping 954 matching lines @@
   __ li(at, scope_info);
   __ Push(at, ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal