Make the detailed reason for deopts mandatory on all platforms.

src/mips/lithium-codegen-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.7
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 798 matching lines @@
     environment->Register(deoptimization_index,
                           translation.index(),
                           (mode == Safepoint::kLazyDeopt) ? pc_offset : -1);
     deoptimizations_.Add(environment, zone());
   }
 }
 
 
 void LCodeGen::DeoptimizeIf(Condition condition, LInstruction* instr,
                             Deoptimizer::BailoutType bailout_type,
-                            Register src1, const Operand& src2,
-                            const char* detail) {
+                            const char* detail, Register src1,
+                            const Operand& src2) {
   LEnvironment* environment = instr->environment();
   RegisterEnvironmentForDeoptimization(environment, Safepoint::kNoLazyDeopt);
   DCHECK(environment->HasBeenRegistered());
   int id = environment->deoptimization_index();
   DCHECK(info()->IsOptimizing() || info()->IsStub());
   Address entry =
       Deoptimizer::GetDeoptimizationEntry(isolate(), id, bailout_type);
   if (entry == NULL) {
     Abort(kBailoutWasNotPrepared);
     return;
@@ skipping 44 matching lines @@
     if (jump_table_.is_empty() ||
         !table_entry.IsEquivalentTo(jump_table_.last())) {
       jump_table_.Add(table_entry, zone());
     }
     __ Branch(&jump_table_.last().label, condition, src1, src2);
   }
 }
 
 
 void LCodeGen::DeoptimizeIf(Condition condition, LInstruction* instr,
-                            Register src1, const Operand& src2,
-                            const char* detail) {
+                            const char* detail, Register src1,
+                            const Operand& src2) {
   Deoptimizer::BailoutType bailout_type = info()->IsStub()
       ? Deoptimizer::LAZY
       : Deoptimizer::EAGER;
-  DeoptimizeIf(condition, instr, bailout_type, src1, src2, detail);
+  DeoptimizeIf(condition, instr, bailout_type, detail, src1, src2);
 }
 
 
 void LCodeGen::PopulateDeoptimizationData(Handle<Code> code) {
   int length = deoptimizations_.length();
   if (length == 0) return;
   Handle<DeoptimizationInputData> data =
       DeoptimizationInputData::New(isolate(), length, TENURED);
 
   Handle<ByteArray> translations =
@@ skipping 209 matching lines @@
   HMod* hmod = instr->hydrogen();
   int32_t mask = divisor < 0 ? -(divisor + 1) : (divisor - 1);
   Label dividend_is_not_negative, done;
 
   if (hmod->CheckFlag(HValue::kLeftCanBeNegative)) {
     __ Branch(&dividend_is_not_negative, ge, dividend, Operand(zero_reg));
     // Note: The code below even works when right contains kMinInt.
     __ subu(dividend, zero_reg, dividend);
     __ And(dividend, dividend, Operand(mask));
     if (hmod->CheckFlag(HValue::kBailoutOnMinusZero)) {
-      DeoptimizeIf(eq, instr, dividend, Operand(zero_reg));
+      DeoptimizeIf(eq, instr, "minus zero", dividend, Operand(zero_reg));
     }
     __ Branch(USE_DELAY_SLOT, &done);
     __ subu(dividend, zero_reg, dividend);
   }
 
   __ bind(&dividend_is_not_negative);
   __ And(dividend, dividend, Operand(mask));
   __ bind(&done);
 }
 
@@ skipping 11 matching lines @@
 
   __ TruncatingDiv(result, dividend, Abs(divisor));
   __ Mul(result, result, Operand(Abs(divisor)));
   __ Subu(result, dividend, Operand(result));
 
   // Check for negative zero.
   HMod* hmod = instr->hydrogen();
   if (hmod->CheckFlag(HValue::kBailoutOnMinusZero)) {
     Label remainder_not_zero;
     __ Branch(&remainder_not_zero, ne, result, Operand(zero_reg));
-    DeoptimizeIf(lt, instr, dividend, Operand(zero_reg));
+    DeoptimizeIf(lt, instr, "minus zero", dividend, Operand(zero_reg));
     __ bind(&remainder_not_zero);
   }
 }
 
 
 void LCodeGen::DoModI(LModI* instr) {
   HMod* hmod = instr->hydrogen();
   const Register left_reg = ToRegister(instr->left());
   const Register right_reg = ToRegister(instr->right());
   const Register result_reg = ToRegister(instr->result());
 
   // div runs in the background while we check for special cases.
   __ Mod(result_reg, left_reg, right_reg);
 
   Label done;
   // Check for x % 0, we have to deopt in this case because we can't return a
   // NaN.
   if (hmod->CheckFlag(HValue::kCanBeDivByZero)) {
-    DeoptimizeIf(eq, instr, right_reg, Operand(zero_reg));
+    DeoptimizeIf(eq, instr, "division by zero", right_reg, Operand(zero_reg));
   }
 
   // Check for kMinInt % -1, div will return kMinInt, which is not what we
   // want. We have to deopt if we care about -0, because we can't return that.
   if (hmod->CheckFlag(HValue::kCanOverflow)) {
     Label no_overflow_possible;
     __ Branch(&no_overflow_possible, ne, left_reg, Operand(kMinInt));
     if (hmod->CheckFlag(HValue::kBailoutOnMinusZero)) {
-      DeoptimizeIf(eq, instr, right_reg, Operand(-1));
+      DeoptimizeIf(eq, instr, "minus zero", right_reg, Operand(-1));
     } else {
       __ Branch(&no_overflow_possible, ne, right_reg, Operand(-1));
       __ Branch(USE_DELAY_SLOT, &done);
       __ mov(result_reg, zero_reg);
     }
     __ bind(&no_overflow_possible);
   }
 
   // If we care about -0, test if the dividend is <0 and the result is 0.
   __ Branch(&done, ge, left_reg, Operand(zero_reg));
   if (hmod->CheckFlag(HValue::kBailoutOnMinusZero)) {
-    DeoptimizeIf(eq, instr, result_reg, Operand(zero_reg));
+    DeoptimizeIf(eq, instr, "minus zero", result_reg, Operand(zero_reg));
   }
   __ bind(&done);
 }
 
 
 void LCodeGen::DoDivByPowerOf2I(LDivByPowerOf2I* instr) {
   Register dividend = ToRegister(instr->dividend());
   int32_t divisor = instr->divisor();
   Register result = ToRegister(instr->result());
   DCHECK(divisor == kMinInt || base::bits::IsPowerOfTwo32(Abs(divisor)));
   DCHECK(!result.is(dividend));
 
   // Check for (0 / -x) that will produce negative zero.
   HDiv* hdiv = instr->hydrogen();
   if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0) {
-    DeoptimizeIf(eq, instr, dividend, Operand(zero_reg));
+    DeoptimizeIf(eq, instr, "minus zero", dividend, Operand(zero_reg));
   }
   // Check for (kMinInt / -1).
   if (hdiv->CheckFlag(HValue::kCanOverflow) && divisor == -1) {
-    DeoptimizeIf(eq, instr, dividend, Operand(kMinInt));
+    DeoptimizeIf(eq, instr, "overflow", dividend, Operand(kMinInt));
   }
   // Deoptimize if remainder will not be 0.
   if (!hdiv->CheckFlag(HInstruction::kAllUsesTruncatingToInt32) &&
       divisor != 1 && divisor != -1) {
     int32_t mask = divisor < 0 ? -(divisor + 1) : (divisor - 1);
     __ And(at, dividend, Operand(mask));
-    DeoptimizeIf(ne, instr, at, Operand(zero_reg));
+    DeoptimizeIf(ne, instr, "lost precision", at, Operand(zero_reg));
   }
 
   if (divisor == -1) {  // Nice shortcut, not needed for correctness.
     __ Subu(result, zero_reg, dividend);
     return;
   }
   uint16_t shift = WhichPowerOf2Abs(divisor);
   if (shift == 0) {
     __ Move(result, dividend);
   } else if (shift == 1) {
@@ skipping 16 matching lines @@
   DCHECK(!dividend.is(result));
 
   if (divisor == 0) {
     DeoptimizeIf(al, instr);
     return;
   }
 
   // Check for (0 / -x) that will produce negative zero.
   HDiv* hdiv = instr->hydrogen();
   if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0) {
-    DeoptimizeIf(eq, instr, dividend, Operand(zero_reg));
+    DeoptimizeIf(eq, instr, "minus zero", dividend, Operand(zero_reg));
   }
 
   __ TruncatingDiv(result, dividend, Abs(divisor));
   if (divisor < 0) __ Subu(result, zero_reg, result);
 
   if (!hdiv->CheckFlag(HInstruction::kAllUsesTruncatingToInt32)) {
     __ Mul(scratch0(), result, Operand(divisor));
     __ Subu(scratch0(), scratch0(), dividend);
-    DeoptimizeIf(ne, instr, scratch0(), Operand(zero_reg));
+    DeoptimizeIf(ne, instr, "lost precision", scratch0(), Operand(zero_reg));
   }
 }
 
 
 // TODO(svenpanne) Refactor this to avoid code duplication with DoFlooringDivI.
 void LCodeGen::DoDivI(LDivI* instr) {
   HBinaryOperation* hdiv = instr->hydrogen();
   Register dividend = ToRegister(instr->dividend());
   Register divisor = ToRegister(instr->divisor());
   const Register result = ToRegister(instr->result());
   Register remainder = ToRegister(instr->temp());
 
   // On MIPS div is asynchronous - it will run in the background while we
   // check for special cases.
   __ Div(remainder, result, dividend, divisor);
 
   // Check for x / 0.
   if (hdiv->CheckFlag(HValue::kCanBeDivByZero)) {
-    DeoptimizeIf(eq, instr, divisor, Operand(zero_reg));
+    DeoptimizeIf(eq, instr, "division by zero", divisor, Operand(zero_reg));
   }
 
   // Check for (0 / -x) that will produce negative zero.
   if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero)) {
     Label left_not_zero;
     __ Branch(&left_not_zero, ne, dividend, Operand(zero_reg));
-    DeoptimizeIf(lt, instr, divisor, Operand(zero_reg));
+    DeoptimizeIf(lt, instr, "minus zero", divisor, Operand(zero_reg));
     __ bind(&left_not_zero);
   }
 
   // Check for (kMinInt / -1).
   if (hdiv->CheckFlag(HValue::kCanOverflow) &&
       !hdiv->CheckFlag(HValue::kAllUsesTruncatingToInt32)) {
     Label left_not_min_int;
     __ Branch(&left_not_min_int, ne, dividend, Operand(kMinInt));
-    DeoptimizeIf(eq, instr, divisor, Operand(-1));
+    DeoptimizeIf(eq, instr, "overflow", divisor, Operand(-1));
     __ bind(&left_not_min_int);
   }
 
   if (!hdiv->CheckFlag(HValue::kAllUsesTruncatingToInt32)) {
-    DeoptimizeIf(ne, instr, remainder, Operand(zero_reg));
+    DeoptimizeIf(ne, instr, "lost precision", remainder, Operand(zero_reg));
   }
 }
 
 
 void LCodeGen::DoMultiplyAddD(LMultiplyAddD* instr) {
   DoubleRegister addend = ToDoubleRegister(instr->addend());
   DoubleRegister multiplier = ToDoubleRegister(instr->multiplier());
   DoubleRegister multiplicand = ToDoubleRegister(instr->multiplicand());
 
   // This is computed in-place.
@@ skipping 25 matching lines @@
   }
 
   // If the divisor is negative, we have to negate and handle edge cases.
 
   // dividend can be the same register as result so save the value of it
   // for checking overflow.
   __ Move(scratch, dividend);
 
   __ Subu(result, zero_reg, dividend);
   if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
-    DeoptimizeIf(eq, instr, result, Operand(zero_reg));
+    DeoptimizeIf(eq, instr, "minus zero", result, Operand(zero_reg));
   }
 
   // Dividing by -1 is basically negation, unless we overflow.
   __ Xor(scratch, scratch, result);
   if (divisor == -1) {
     if (instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) {
-      DeoptimizeIf(ge, instr, scratch, Operand(zero_reg));
+      DeoptimizeIf(ge, instr, "overflow", scratch, Operand(zero_reg));
     }
     return;
   }
 
   // If the negation could not overflow, simply shifting is OK.
   if (!instr->hydrogen()->CheckFlag(HValue::kLeftCanBeMinInt)) {
     __ sra(result, result, shift);
     return;
   }
 
@@ skipping 14 matching lines @@
   DCHECK(!dividend.is(result));
 
   if (divisor == 0) {
     DeoptimizeIf(al, instr);
     return;
   }
 
   // Check for (0 / -x) that will produce negative zero.
   HMathFloorOfDiv* hdiv = instr->hydrogen();
   if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero) && divisor < 0) {
-    DeoptimizeIf(eq, instr, dividend, Operand(zero_reg));
+    DeoptimizeIf(eq, instr, "minus zero", dividend, Operand(zero_reg));
   }
 
   // Easy case: We need no dynamic check for the dividend and the flooring
   // division is the same as the truncating division.
   if ((divisor > 0 && !hdiv->CheckFlag(HValue::kLeftCanBeNegative)) ||
       (divisor < 0 && !hdiv->CheckFlag(HValue::kLeftCanBePositive))) {
     __ TruncatingDiv(result, dividend, Abs(divisor));
     if (divisor < 0) __ Subu(result, zero_reg, result);
     return;
   }
@@ skipping 23 matching lines @@
   Register dividend = ToRegister(instr->dividend());
   Register divisor = ToRegister(instr->divisor());
   const Register result = ToRegister(instr->result());
   Register remainder = scratch0();
   // On MIPS div is asynchronous - it will run in the background while we
   // check for special cases.
   __ Div(remainder, result, dividend, divisor);
 
   // Check for x / 0.
   if (hdiv->CheckFlag(HValue::kCanBeDivByZero)) {
-    DeoptimizeIf(eq, instr, divisor, Operand(zero_reg));
+    DeoptimizeIf(eq, instr, "division by zero", divisor, Operand(zero_reg));
   }
 
   // Check for (0 / -x) that will produce negative zero.
   if (hdiv->CheckFlag(HValue::kBailoutOnMinusZero)) {
     Label left_not_zero;
     __ Branch(&left_not_zero, ne, dividend, Operand(zero_reg));
-    DeoptimizeIf(lt, instr, divisor, Operand(zero_reg));
+    DeoptimizeIf(lt, instr, "minus zero", divisor, Operand(zero_reg));
     __ bind(&left_not_zero);
   }
 
   // Check for (kMinInt / -1).
   if (hdiv->CheckFlag(HValue::kCanOverflow) &&
       !hdiv->CheckFlag(HValue::kAllUsesTruncatingToInt32)) {
     Label left_not_min_int;
     __ Branch(&left_not_min_int, ne, dividend, Operand(kMinInt));
-    DeoptimizeIf(eq, instr, divisor, Operand(-1));
+    DeoptimizeIf(eq, instr, "overflow", divisor, Operand(-1));
     __ bind(&left_not_min_int);
   }
 
   // We performed a truncating division. Correct the result if necessary.
   Label done;
   __ Branch(&done, eq, remainder, Operand(zero_reg), USE_DELAY_SLOT);
   __ Xor(remainder, remainder, Operand(divisor));
   __ Branch(&done, ge, remainder, Operand(zero_reg));
   __ Subu(result, result, Operand(1));
   __ bind(&done);
@@ skipping 10 matching lines @@
   bool bailout_on_minus_zero =
     instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero);
   bool overflow = instr->hydrogen()->CheckFlag(HValue::kCanOverflow);
 
   if (right_op->IsConstantOperand()) {
     int32_t constant = ToInteger32(LConstantOperand::cast(right_op));
 
     if (bailout_on_minus_zero && (constant < 0)) {
       // The case of a null constant will be handled separately.
       // If constant is negative and left is null, the result should be -0.
-      DeoptimizeIf(eq, instr, left, Operand(zero_reg));
+      DeoptimizeIf(eq, instr, "minus zero", left, Operand(zero_reg));
     }
 
     switch (constant) {
       case -1:
         if (overflow) {
           __ SubuAndCheckForOverflow(result, zero_reg, left, scratch);
-          DeoptimizeIf(lt, instr, scratch, Operand(zero_reg));
+          DeoptimizeIf(lt, instr, "overflow", scratch, Operand(zero_reg));
         } else {
           __ Subu(result, zero_reg, left);
         }
         break;
       case 0:
         if (bailout_on_minus_zero) {
           // If left is strictly negative and the constant is null, the
           // result is -0. Deoptimize if required, otherwise return 0.
-          DeoptimizeIf(lt, instr, left, Operand(zero_reg));
+          DeoptimizeIf(lt, instr, "minus zero", left, Operand(zero_reg));
         }
         __ mov(result, zero_reg);
         break;
       case 1:
         // Nothing to do.
         __ Move(result, left);
         break;
       default:
         // Multiplying by powers of two and powers of two plus or minus
         // one can be done faster with shifted operands.
@@ skipping 31 matching lines @@
 
     if (overflow) {
       // hi:lo = left * right.
       if (instr->hydrogen()->representation().IsSmi()) {
         __ SmiUntag(result, left);
         __ Mul(scratch, result, result, right);
       } else {
         __ Mul(scratch, result, left, right);
       }
       __ sra(at, result, 31);
-      DeoptimizeIf(ne, instr, scratch, Operand(at));
+      DeoptimizeIf(ne, instr, "overflow", scratch, Operand(at));
     } else {
       if (instr->hydrogen()->representation().IsSmi()) {
         __ SmiUntag(result, left);
         __ Mul(result, result, right);
       } else {
         __ Mul(result, left, right);
       }
     }
 
     if (bailout_on_minus_zero) {
       Label done;
       __ Xor(at, left, right);
       __ Branch(&done, ge, at, Operand(zero_reg));
       // Bail out if the result is minus zero.
-      DeoptimizeIf(eq, instr, result, Operand(zero_reg));
+      DeoptimizeIf(eq, instr, "minus zero", result, Operand(zero_reg));
       __ bind(&done);
     }
   }
 }
 
 
 void LCodeGen::DoBitI(LBitI* instr) {
   LOperand* left_op = instr->left();
   LOperand* right_op = instr->right();
   DCHECK(left_op->IsRegister());
@@ skipping 43 matching lines @@
     switch (instr->op()) {
       case Token::ROR:
         __ Ror(result, left, Operand(ToRegister(right_op)));
         break;
       case Token::SAR:
         __ srav(result, left, ToRegister(right_op));
         break;
       case Token::SHR:
         __ srlv(result, left, ToRegister(right_op));
         if (instr->can_deopt()) {
-          DeoptimizeIf(lt, instr, result, Operand(zero_reg));
+          DeoptimizeIf(lt, instr, "negative value", result, Operand(zero_reg));
         }
         break;
       case Token::SHL:
         __ sllv(result, left, ToRegister(right_op));
         break;
       default:
         UNREACHABLE();
         break;
     }
   } else {
@@ skipping 14 matching lines @@
         } else {
           __ Move(result, left);
         }
         break;
       case Token::SHR:
         if (shift_count != 0) {
           __ srl(result, left, shift_count);
         } else {
           if (instr->can_deopt()) {
             __ And(at, left, Operand(0x80000000));
-            DeoptimizeIf(ne, instr, at, Operand(zero_reg));
+            DeoptimizeIf(ne, instr, "negative value", at, Operand(zero_reg));
           }
           __ Move(result, left);
         }
         break;
       case Token::SHL:
         if (shift_count != 0) {
           if (instr->hydrogen_value()->representation().IsSmi() &&
               instr->can_deopt()) {
             if (shift_count != 1) {
               __ sll(result, left, shift_count - 1);
               __ SmiTagCheckOverflow(result, result, scratch);
             } else {
               __ SmiTagCheckOverflow(result, left, scratch);
             }
-            DeoptimizeIf(lt, instr, scratch, Operand(zero_reg));
+            DeoptimizeIf(lt, instr, "overflow", scratch, Operand(zero_reg));
           } else {
             __ sll(result, left, shift_count);
           }
         } else {
           __ Move(result, left);
         }
         break;
       default:
         UNREACHABLE();
         break;
@@ skipping 27 matching lines @@
                                  overflow);  // Reg at also used as scratch.
     } else {
       DCHECK(right->IsRegister());
       // Due to overflow check macros not supporting constant operands,
       // handling the IsConstantOperand case was moved to prev if clause.
       __ SubuAndCheckForOverflow(ToRegister(result),
                                  ToRegister(left),
                                  ToRegister(right),
                                  overflow);  // Reg at also used as scratch.
     }
-    DeoptimizeIf(lt, instr, overflow, Operand(zero_reg));
+    DeoptimizeIf(lt, instr, "overflow", overflow, Operand(zero_reg));
   }
 }
 
 
 void LCodeGen::DoConstantI(LConstantI* instr) {
   __ li(ToRegister(instr->result()), Operand(instr->value()));
 }
 
 
 void LCodeGen::DoConstantS(LConstantS* instr) {
@@ skipping 33 matching lines @@
   Register result = ToRegister(instr->result());
   Register scratch = ToRegister(instr->temp());
   Smi* index = instr->index();
   Label runtime, done;
   DCHECK(object.is(a0));
   DCHECK(result.is(v0));
   DCHECK(!scratch.is(scratch0()));
   DCHECK(!scratch.is(object));
 
   __ SmiTst(object, at);
-  DeoptimizeIf(eq, instr, at, Operand(zero_reg));
+  DeoptimizeIf(eq, instr, "Smi", at, Operand(zero_reg));
   __ GetObjectType(object, scratch, scratch);
-  DeoptimizeIf(ne, instr, scratch, Operand(JS_DATE_TYPE));
+  DeoptimizeIf(ne, instr, "not a date object", scratch, Operand(JS_DATE_TYPE));
 
   if (index->value() == 0) {
     __ lw(result, FieldMemOperand(object, JSDate::kValueOffset));
   } else {
     if (index->value() < JSDate::kFirstUncachedField) {
       ExternalReference stamp = ExternalReference::date_cache_stamp(isolate());
       __ li(scratch, Operand(stamp));
       __ lw(scratch, MemOperand(scratch));
       __ lw(scratch0(), FieldMemOperand(object, JSDate::kCacheStampOffset));
       __ Branch(&runtime, ne, scratch, Operand(scratch0()));
@@ skipping 114 matching lines @@
                                  overflow);  // Reg at also used as scratch.
     } else {
       DCHECK(right->IsRegister());
       // Due to overflow check macros not supporting constant operands,
       // handling the IsConstantOperand case was moved to prev if clause.
       __ AdduAndCheckForOverflow(ToRegister(result),
                                  ToRegister(left),
                                  ToRegister(right),
                                  overflow);  // Reg at also used as scratch.
     }
-    DeoptimizeIf(lt, instr, overflow, Operand(zero_reg));
+    DeoptimizeIf(lt, instr, "overflow", overflow, Operand(zero_reg));
   }
 }
 
 
 void LCodeGen::DoMathMinMax(LMathMinMax* instr) {
   LOperand* left = instr->left();
   LOperand* right = instr->right();
   HMathMinMax::Operation operation = instr->hydrogen()->operation();
   Condition condition = (operation == HMathMinMax::kMathMin) ? le : ge;
   if (instr->hydrogen()->representation().IsSmiOrInteger32()) {
@@ skipping 240 matching lines @@
         __ Branch(instr->FalseLabel(chunk_), eq, reg, Operand(at));
       }
 
       if (expected.Contains(ToBooleanStub::SMI)) {
         // Smis: 0 -> false, all other -> true.
         __ Branch(instr->FalseLabel(chunk_), eq, reg, Operand(zero_reg));
         __ JumpIfSmi(reg, instr->TrueLabel(chunk_));
       } else if (expected.NeedsMap()) {
         // If we need a map later and have a Smi -> deopt.
         __ SmiTst(reg, at);
-        DeoptimizeIf(eq, instr, at, Operand(zero_reg));
+        DeoptimizeIf(eq, instr, "Smi", at, Operand(zero_reg));
       }
 
       const Register map = scratch0();
       if (expected.NeedsMap()) {
         __ lw(map, FieldMemOperand(reg, HeapObject::kMapOffset));
         if (expected.CanBeUndetectable()) {
           // Undetectable -> false.
           __ lbu(at, FieldMemOperand(map, Map::kBitFieldOffset));
           __ And(at, at, Operand(1 << Map::kIsUndetectable));
           __ Branch(instr->FalseLabel(chunk_), ne, at, Operand(zero_reg));
@@ skipping 35 matching lines @@
         __ BranchF(instr->TrueLabel(chunk_), instr->FalseLabel(chunk_),
                    ne, dbl_scratch, kDoubleRegZero);
         // Falls through if dbl_scratch == 0.
         __ Branch(instr->FalseLabel(chunk_));
         __ bind(&not_heap_number);
       }
 
       if (!expected.IsGeneric()) {
         // We've seen something for the first time -> deopt.
         // This can only happen if we are not generic already.
-        DeoptimizeIf(al, instr, zero_reg, Operand(zero_reg));
+        DeoptimizeIf(al, instr, "unexpected object", zero_reg,
+                     Operand(zero_reg));
       }
     }
   }
 }
 
 
 void LCodeGen::EmitGoto(int block) {
   if (!IsNextEmittedBlock(block)) {
     __ jmp(chunk_->GetAssemblyLabel(LookupDestination(block)));
   }
@@ skipping 623 matching lines @@
   }
 }
 
 
 void LCodeGen::DoLoadGlobalCell(LLoadGlobalCell* instr) {
   Register result = ToRegister(instr->result());
   __ li(at, Operand(Handle<Object>(instr->hydrogen()->cell().handle())));
   __ lw(result, FieldMemOperand(at, Cell::kValueOffset));
   if (instr->hydrogen()->RequiresHoleCheck()) {
     __ LoadRoot(at, Heap::kTheHoleValueRootIndex);
-    DeoptimizeIf(eq, instr, result, Operand(at));
+    DeoptimizeIf(eq, instr, "hole", result, Operand(at));
   }
 }
 
 
 template <class T>
 void LCodeGen::EmitVectorLoadICRegisters(T* instr) {
   DCHECK(FLAG_vector_ics);
   Register vector = ToRegister(instr->temp_vector());
   DCHECK(vector.is(VectorLoadICDescriptor::VectorRegister()));
   __ li(vector, instr->hydrogen()->feedback_vector());
@@ skipping 29 matching lines @@
 
   // If the cell we are storing to contains the hole it could have
   // been deleted from the property dictionary. In that case, we need
   // to update the property details in the property dictionary to mark
   // it as no longer deleted.
   if (instr->hydrogen()->RequiresHoleCheck()) {
     // We use a temp to check the payload.
     Register payload = ToRegister(instr->temp());
     __ lw(payload, FieldMemOperand(cell, Cell::kValueOffset));
     __ LoadRoot(at, Heap::kTheHoleValueRootIndex);
-    DeoptimizeIf(eq, instr, payload, Operand(at));
+    DeoptimizeIf(eq, instr, "hole", payload, Operand(at));
   }
 
   // Store the value.
   __ sw(value, FieldMemOperand(cell, Cell::kValueOffset));
   // Cells are always rescanned, so no write barrier here.
 }
 
 
 
 void LCodeGen::DoLoadContextSlot(LLoadContextSlot* instr) {
   Register context = ToRegister(instr->context());
   Register result = ToRegister(instr->result());
 
   __ lw(result, ContextOperand(context, instr->slot_index()));
   if (instr->hydrogen()->RequiresHoleCheck()) {
     __ LoadRoot(at, Heap::kTheHoleValueRootIndex);
 
     if (instr->hydrogen()->DeoptimizesOnHole()) {
-      DeoptimizeIf(eq, instr, result, Operand(at));
+      DeoptimizeIf(eq, instr, "hole", result, Operand(at));
     } else {
       Label is_not_hole;
       __ Branch(&is_not_hole, ne, result, Operand(at));
       __ LoadRoot(result, Heap::kUndefinedValueRootIndex);
       __ bind(&is_not_hole);
     }
   }
 }
 
 
 void LCodeGen::DoStoreContextSlot(LStoreContextSlot* instr) {
   Register context = ToRegister(instr->context());
   Register value = ToRegister(instr->value());
   Register scratch = scratch0();
   MemOperand target = ContextOperand(context, instr->slot_index());
 
   Label skip_assignment;
 
   if (instr->hydrogen()->RequiresHoleCheck()) {
     __ lw(scratch, target);
     __ LoadRoot(at, Heap::kTheHoleValueRootIndex);
 
     if (instr->hydrogen()->DeoptimizesOnHole()) {
-      DeoptimizeIf(eq, instr, scratch, Operand(at));
+      DeoptimizeIf(eq, instr, "hole", scratch, Operand(at));
     } else {
       __ Branch(&skip_assignment, ne, scratch, Operand(at));
     }
   }
 
   __ sw(value, target);
   if (instr->hydrogen()->NeedsWriteBarrier()) {
     SmiCheck check_needed =
         instr->hydrogen()->value()->type().IsHeapObject()
             ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
@@ skipping 58 matching lines @@
   Register scratch = scratch0();
   Register function = ToRegister(instr->function());
   Register result = ToRegister(instr->result());
 
   // Get the prototype or initial map from the function.
   __ lw(result,
          FieldMemOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
 
   // Check that the function has a prototype or an initial map.
   __ LoadRoot(at, Heap::kTheHoleValueRootIndex);
-  DeoptimizeIf(eq, instr, result, Operand(at));
+  DeoptimizeIf(eq, instr, "hole", result, Operand(at));
 
   // If the function does not have an initial map, we're done.
   Label done;
   __ GetObjectType(result, scratch, scratch);
   __ Branch(&done, ne, scratch, Operand(MAP_TYPE));
 
   // Get the prototype from the initial map.
   __ lw(result, FieldMemOperand(result, Map::kPrototypeOffset));
 
   // All done.
@@ skipping 115 matching lines @@
         __ lhu(result, mem_operand);
         break;
       case EXTERNAL_INT32_ELEMENTS:
       case INT32_ELEMENTS:
         __ lw(result, mem_operand);
         break;
       case EXTERNAL_UINT32_ELEMENTS:
       case UINT32_ELEMENTS:
         __ lw(result, mem_operand);
         if (!instr->hydrogen()->CheckFlag(HInstruction::kUint32)) {
-          DeoptimizeIf(Ugreater_equal, instr, result, Operand(0x80000000));
+          DeoptimizeIf(Ugreater_equal, instr, "negative value", result,
+                       Operand(0x80000000));
         }
         break;
       case FLOAT32_ELEMENTS:
       case FLOAT64_ELEMENTS:
       case EXTERNAL_FLOAT32_ELEMENTS:
       case EXTERNAL_FLOAT64_ELEMENTS:
       case FAST_DOUBLE_ELEMENTS:
       case FAST_ELEMENTS:
       case FAST_SMI_ELEMENTS:
       case FAST_HOLEY_DOUBLE_ELEMENTS:
@@ skipping 32 matching lines @@
     int shift_size = (instr->hydrogen()->key()->representation().IsSmi())
         ? (element_size_shift - kSmiTagSize) : element_size_shift;
     __ sll(at, key, shift_size);
     __ Addu(scratch, scratch, at);
   }
 
   __ ldc1(result, MemOperand(scratch));
 
   if (instr->hydrogen()->RequiresHoleCheck()) {
     __ lw(scratch, MemOperand(scratch, kHoleNanUpper32Offset));
-    DeoptimizeIf(eq, instr, scratch, Operand(kHoleNanUpper32));
+    DeoptimizeIf(eq, instr, "hole", scratch, Operand(kHoleNanUpper32));
   }
 }
 
 
 void LCodeGen::DoLoadKeyedFixedArray(LLoadKeyed* instr) {
   Register elements = ToRegister(instr->elements());
   Register result = ToRegister(instr->result());
   Register scratch = scratch0();
   Register store_base = scratch;
   int offset = instr->base_offset();
@@ skipping 15 matching lines @@
       __ sll(scratch, key, kPointerSizeLog2);
       __ addu(scratch, elements, scratch);
     }
   }
   __ lw(result, MemOperand(store_base, offset));
 
   // Check for the hole value.
   if (instr->hydrogen()->RequiresHoleCheck()) {
     if (IsFastSmiElementsKind(instr->hydrogen()->elements_kind())) {
       __ SmiTst(result, scratch);
-      DeoptimizeIf(ne, instr, scratch, Operand(zero_reg));
+      DeoptimizeIf(ne, instr, "not a Smi", scratch, Operand(zero_reg));
     } else {
       __ LoadRoot(scratch, Heap::kTheHoleValueRootIndex);
-      DeoptimizeIf(eq, instr, result, Operand(scratch));
+      DeoptimizeIf(eq, instr, "hole", result, Operand(scratch));
     }
   }
 }
 
 
 void LCodeGen::DoLoadKeyed(LLoadKeyed* instr) {
   if (instr->is_typed_elements()) {
     DoLoadKeyedExternalArray(instr);
   } else if (instr->hydrogen()->representation().IsDouble()) {
     DoLoadKeyedFixedDoubleArray(instr);
@@ skipping 125 matching lines @@
   }
 
   // Normal function. Replace undefined or null with global receiver.
   __ LoadRoot(scratch, Heap::kNullValueRootIndex);
   __ Branch(&global_object, eq, receiver, Operand(scratch));
   __ LoadRoot(scratch, Heap::kUndefinedValueRootIndex);
   __ Branch(&global_object, eq, receiver, Operand(scratch));
 
   // Deoptimize if the receiver is not a JS object.
   __ SmiTst(receiver, scratch);
-  DeoptimizeIf(eq, instr, scratch, Operand(zero_reg));
+  DeoptimizeIf(eq, instr, "Smi", scratch, Operand(zero_reg));
 
   __ GetObjectType(receiver, scratch, scratch);
-  DeoptimizeIf(lt, instr, scratch, Operand(FIRST_SPEC_OBJECT_TYPE));
+  DeoptimizeIf(lt, instr, "not a JavaScript object", scratch,
+               Operand(FIRST_SPEC_OBJECT_TYPE));
 
   __ Branch(&result_in_receiver);
   __ bind(&global_object);
   __ lw(result, FieldMemOperand(function, JSFunction::kContextOffset));
   __ lw(result,
         ContextOperand(result, Context::GLOBAL_OBJECT_INDEX));
   __ lw(result,
         FieldMemOperand(result, GlobalObject::kGlobalProxyOffset));
 
   if (result.is(receiver)) {
@@ skipping 14 matching lines @@
   Register length = ToRegister(instr->length());
   Register elements = ToRegister(instr->elements());
   Register scratch = scratch0();
   DCHECK(receiver.is(a0));  // Used for parameter count.
   DCHECK(function.is(a1));  // Required by InvokeFunction.
   DCHECK(ToRegister(instr->result()).is(v0));
 
   // Copy the arguments to this function possibly from the
   // adaptor frame below it.
   const uint32_t kArgumentsLimit = 1 * KB;
-  DeoptimizeIf(hi, instr, length, Operand(kArgumentsLimit));
+  DeoptimizeIf(hi, instr, "too many arguments", length,
+               Operand(kArgumentsLimit));
 
   // Push the receiver and use the register to keep the original
   // number of arguments.
   __ push(receiver);
   __ Move(receiver, length);
   // The arguments are at a one pointer size offset from elements.
   __ Addu(elements, elements, Operand(1 * kPointerSize));
 
   // Loop through the arguments pushing them onto the execution
   // stack.
@@ skipping 109 matching lines @@
 void LCodeGen::DoDeferredMathAbsTaggedHeapNumber(LMathAbs* instr) {
   DCHECK(instr->context() != NULL);
   DCHECK(ToRegister(instr->context()).is(cp));
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());
   Register scratch = scratch0();
 
   // Deoptimize if not a heap number.
   __ lw(scratch, FieldMemOperand(input, HeapObject::kMapOffset));
   __ LoadRoot(at, Heap::kHeapNumberMapRootIndex);
-  DeoptimizeIf(ne, instr, scratch, Operand(at));
+  DeoptimizeIf(ne, instr, "not a heap number", scratch, Operand(at));
 
   Label done;
   Register exponent = scratch0();
   scratch = no_reg;
   __ lw(exponent, FieldMemOperand(input, HeapNumber::kExponentOffset));
   // Check the sign of the argument. If the argument is positive, just
   // return it.
   __ Move(result, input);
   __ And(at, exponent, Operand(HeapNumber::kSignMask));
   __ Branch(&done, eq, at, Operand(zero_reg));
@@ skipping 46 matching lines @@
 
 void LCodeGen::EmitIntegerMathAbs(LMathAbs* instr) {
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());
   Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm_);
   Label done;
   __ Branch(USE_DELAY_SLOT, &done, ge, input, Operand(zero_reg));
   __ mov(result, input);
   __ subu(result, zero_reg, input);
   // Overflow if result is still negative, i.e. 0x80000000.
-  DeoptimizeIf(lt, instr, result, Operand(zero_reg));
+  DeoptimizeIf(lt, instr, "overflow", result, Operand(zero_reg));
   __ bind(&done);
 }
 
 
 void LCodeGen::DoMathAbs(LMathAbs* instr) {
   // Class for deferred case.
   class DeferredMathAbsTaggedHeapNumber FINAL : public LDeferredCode {
    public:
     DeferredMathAbsTaggedHeapNumber(LCodeGen* codegen, LMathAbs* instr)
         : LDeferredCode(codegen), instr_(instr) { }
@@ skipping 33 matching lines @@
   Register except_flag = ToRegister(instr->temp());
 
   __ EmitFPUTruncate(kRoundToMinusInf,
                      result,
                      input,
                      scratch1,
                      double_scratch0(),
                      except_flag);
 
   // Deopt if the operation did not succeed.
-  DeoptimizeIf(ne, instr, except_flag, Operand(zero_reg));
+  DeoptimizeIf(ne, instr, "lost precision or NaN", except_flag,
+               Operand(zero_reg));
 
   if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
     // Test for -0.
     Label done;
     __ Branch(&done, ne, result, Operand(zero_reg));
     __ Mfhc1(scratch1, input);
     __ And(scratch1, scratch1, Operand(HeapNumber::kSignMask));
-    DeoptimizeIf(ne, instr, scratch1, Operand(zero_reg));
+    DeoptimizeIf(ne, instr, "minus zero", scratch1, Operand(zero_reg));
     __ bind(&done);
   }
 }
 
 
 void LCodeGen::DoMathRound(LMathRound* instr) {
   DoubleRegister input = ToDoubleRegister(instr->value());
   Register result = ToRegister(instr->result());
   DoubleRegister double_scratch1 = ToDoubleRegister(instr->temp());
   Register scratch = scratch0();
@@ skipping 12 matching lines @@
   __ mov(result, zero_reg);
   if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
     __ Branch(&check_sign_on_zero);
   } else {
     __ Branch(&done);
   }
   __ bind(&skip1);
 
   // The following conversion will not work with numbers
   // outside of ]-2^32, 2^32[.
-  DeoptimizeIf(ge, instr, scratch, Operand(HeapNumber::kExponentBias + 32));
+  DeoptimizeIf(ge, instr, "overflow", scratch,
+               Operand(HeapNumber::kExponentBias + 32));
 
   // Save the original sign for later comparison.
   __ And(scratch, result, Operand(HeapNumber::kSignMask));
 
   __ Move(double_scratch0(), 0.5);
   __ add_d(double_scratch0(), input, double_scratch0());
 
   // Check sign of the result: if the sign changed, the input
   // value was in ]0.5, 0[ and the result should be -0.
   __ Mfhc1(result, double_scratch0());
   __ Xor(result, result, Operand(scratch));
   if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
     // ARM uses 'mi' here, which is 'lt'
-    DeoptimizeIf(lt, instr, result, Operand(zero_reg));
+    DeoptimizeIf(lt, instr, "minus zero", result, Operand(zero_reg));
   } else {
     Label skip2;
     // ARM uses 'mi' here, which is 'lt'
     // Negating it results in 'ge'
     __ Branch(&skip2, ge, result, Operand(zero_reg));
     __ mov(result, zero_reg);
     __ Branch(&done);
     __ bind(&skip2);
   }
 
   Register except_flag = scratch;
   __ EmitFPUTruncate(kRoundToMinusInf,
                      result,
                      double_scratch0(),
                      at,
                      double_scratch1,
                      except_flag);
 
-  DeoptimizeIf(ne, instr, except_flag, Operand(zero_reg));
+  DeoptimizeIf(ne, instr, "lost precision or NaN", except_flag,
+               Operand(zero_reg));
 
   if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
     // Test for -0.
     __ Branch(&done, ne, result, Operand(zero_reg));
     __ bind(&check_sign_on_zero);
     __ Mfhc1(scratch, input);
     __ And(scratch, scratch, Operand(HeapNumber::kSignMask));
-    DeoptimizeIf(ne, instr, scratch, Operand(zero_reg));
+    DeoptimizeIf(ne, instr, "minus zero", scratch, Operand(zero_reg));
   }
   __ bind(&done);
 }
 
 
 void LCodeGen::DoMathFround(LMathFround* instr) {
   DoubleRegister input = ToDoubleRegister(instr->value());
   DoubleRegister result = ToDoubleRegister(instr->result());
   __ cvt_s_d(result.low(), input);
   __ cvt_d_s(result, result.low());
@@ skipping 45 matching lines @@
 
   if (exponent_type.IsSmi()) {
     MathPowStub stub(isolate(), MathPowStub::TAGGED);
     __ CallStub(&stub);
   } else if (exponent_type.IsTagged()) {
     Label no_deopt;
     __ JumpIfSmi(tagged_exponent, &no_deopt);
     DCHECK(!t3.is(tagged_exponent));
     __ lw(t3, FieldMemOperand(tagged_exponent, HeapObject::kMapOffset));
     __ LoadRoot(at, Heap::kHeapNumberMapRootIndex);
-    DeoptimizeIf(ne, instr, t3, Operand(at));
+    DeoptimizeIf(ne, instr, "not a heap number", t3, Operand(at));
     __ bind(&no_deopt);
     MathPowStub stub(isolate(), MathPowStub::TAGGED);
     __ CallStub(&stub);
   } else if (exponent_type.IsInteger32()) {
     MathPowStub stub(isolate(), MathPowStub::INTEGER);
     __ CallStub(&stub);
   } else {
     DCHECK(exponent_type.IsDouble());
     MathPowStub stub(isolate(), MathPowStub::DOUBLE);
     __ CallStub(&stub);
@@ skipping 322 matching lines @@
   } else {
     reg = ToRegister(instr->index());
     operand = ToOperand(instr->length());
   }
   if (FLAG_debug_code && instr->hydrogen()->skip_check()) {
     Label done;
     __ Branch(&done, NegateCondition(cc), reg, operand);
     __ stop("eliminated bounds check failed");
     __ bind(&done);
   } else {
-    DeoptimizeIf(cc, instr, reg, operand);
+    DeoptimizeIf(cc, instr, "out of bounds", reg, operand);
   }
 }
 
 
 void LCodeGen::DoStoreKeyedExternalArray(LStoreKeyed* instr) {
   Register external_pointer = ToRegister(instr->elements());
   Register key = no_reg;
   ElementsKind elements_kind = instr->elements_kind();
   bool key_is_constant = instr->key()->IsConstantOperand();
   int constant_key = 0;
@@ skipping 572 matching lines @@
 }
 
 
 void LCodeGen::DoSmiTag(LSmiTag* instr) {
   HChange* hchange = instr->hydrogen();
   Register input = ToRegister(instr->value());
   Register output = ToRegister(instr->result());
   if (hchange->CheckFlag(HValue::kCanOverflow) &&
       hchange->value()->CheckFlag(HValue::kUint32)) {
     __ And(at, input, Operand(0xc0000000));
-    DeoptimizeIf(ne, instr, at, Operand(zero_reg));
+    DeoptimizeIf(ne, instr, "overflow", at, Operand(zero_reg));
   }
   if (hchange->CheckFlag(HValue::kCanOverflow) &&
       !hchange->value()->CheckFlag(HValue::kUint32)) {
     __ SmiTagCheckOverflow(output, input, at);
-    DeoptimizeIf(lt, instr, at, Operand(zero_reg));
+    DeoptimizeIf(lt, instr, "overflow", at, Operand(zero_reg));
   } else {
     __ SmiTag(output, input);
   }
 }
 
 
 void LCodeGen::DoSmiUntag(LSmiUntag* instr) {
   Register scratch = scratch0();
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());
   if (instr->needs_check()) {
     STATIC_ASSERT(kHeapObjectTag == 1);
     // If the input is a HeapObject, value of scratch won't be zero.
     __ And(scratch, input, Operand(kHeapObjectTag));
     __ SmiUntag(result, input);
-    DeoptimizeIf(ne, instr, scratch, Operand(zero_reg));
+    DeoptimizeIf(ne, instr, "not a Smi", scratch, Operand(zero_reg));
   } else {
     __ SmiUntag(result, input);
   }
 }
 
 
 void LCodeGen::EmitNumberUntagD(LNumberUntagD* instr, Register input_reg,
                                 DoubleRegister result_reg,
                                 NumberUntagDMode mode) {
   bool can_convert_undefined_to_nan =
       instr->hydrogen()->can_convert_undefined_to_nan();
   bool deoptimize_on_minus_zero = instr->hydrogen()->deoptimize_on_minus_zero();
 
   Register scratch = scratch0();
   Label convert, load_smi, done;
   if (mode == NUMBER_CANDIDATE_IS_ANY_TAGGED) {
     // Smi check.
     __ UntagAndJumpIfSmi(scratch, input_reg, &load_smi);
     // Heap number map check.
     __ lw(scratch, FieldMemOperand(input_reg, HeapObject::kMapOffset));
     __ LoadRoot(at, Heap::kHeapNumberMapRootIndex);
     if (can_convert_undefined_to_nan) {
       __ Branch(&convert, ne, scratch, Operand(at));
     } else {
-      DeoptimizeIf(ne, instr, scratch, Operand(at));
+      DeoptimizeIf(ne, instr, "not a heap number", scratch, Operand(at));
     }
     // Load heap number.
     __ ldc1(result_reg, FieldMemOperand(input_reg, HeapNumber::kValueOffset));
     if (deoptimize_on_minus_zero) {
       __ mfc1(at, result_reg.low());
       __ Branch(&done, ne, at, Operand(zero_reg));
       __ Mfhc1(scratch, result_reg);
-      DeoptimizeIf(eq, instr, scratch, Operand(HeapNumber::kSignMask));
+      DeoptimizeIf(eq, instr, "minus zero", scratch,
+                   Operand(HeapNumber::kSignMask));
     }
     __ Branch(&done);
     if (can_convert_undefined_to_nan) {
       __ bind(&convert);
       // Convert undefined (and hole) to NaN.
       __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
-      DeoptimizeIf(ne, instr, input_reg, Operand(at));
+      DeoptimizeIf(ne, instr, "not a heap number/undefined", input_reg,
+                   Operand(at));
       __ LoadRoot(scratch, Heap::kNanValueRootIndex);
       __ ldc1(result_reg, FieldMemOperand(scratch, HeapNumber::kValueOffset));
       __ Branch(&done);
     }
   } else {
     __ SmiUntag(scratch, input_reg);
     DCHECK(mode == NUMBER_CANDIDATE_IS_SMI);
   }
   // Smi to double register conversion
   __ bind(&load_smi);
@@ skipping 43 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);
-    DeoptimizeIf(ne, instr, scratch2, Operand(at), "cannot truncate");
+    DeoptimizeIf(ne, instr, "not a heap number/undefined/true/false", scratch2,
+                 Operand(at));
     __ Branch(USE_DELAY_SLOT, &done);
     __ mov(input_reg, zero_reg);  // In delay slot.
   } else {
-    DeoptimizeIf(ne, instr, scratch1, Operand(at), "not a heap number");
+    DeoptimizeIf(ne, instr, "not a heap number", 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);
 
-    DeoptimizeIf(ne, instr, except_flag, Operand(zero_reg),
-                 "lost precision or NaN");
+    DeoptimizeIf(ne, instr, "lost precision or NaN", except_flag,
+                 Operand(zero_reg));
 
     if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
       __ Branch(&done, ne, input_reg, Operand(zero_reg));
 
       __ Mfhc1(scratch1, double_scratch);
       __ And(scratch1, scratch1, Operand(HeapNumber::kSignMask));
-      DeoptimizeIf(ne, instr, scratch1, Operand(zero_reg), "minus zero");
+      DeoptimizeIf(ne, instr, "minus zero", scratch1, Operand(zero_reg));
     }
   }
   __ bind(&done);
 }
 
 
 void LCodeGen::DoTaggedToI(LTaggedToI* instr) {
   class DeferredTaggedToI FINAL : public LDeferredCode {
    public:
     DeferredTaggedToI(LCodeGen* codegen, LTaggedToI* instr)
@@ skipping 56 matching lines @@
 
     __ EmitFPUTruncate(kRoundToMinusInf,
                        result_reg,
                        double_input,
                        scratch1,
                        double_scratch0(),
                        except_flag,
                        kCheckForInexactConversion);
 
     // Deopt if the operation did not succeed (except_flag != 0).
-    DeoptimizeIf(ne, instr, except_flag, Operand(zero_reg));
+    DeoptimizeIf(ne, instr, "lost precision or NaN", except_flag,
+                 Operand(zero_reg));
 
     if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
       Label done;
       __ Branch(&done, ne, result_reg, Operand(zero_reg));
       __ Mfhc1(scratch1, double_input);
       __ And(scratch1, scratch1, Operand(HeapNumber::kSignMask));
-      DeoptimizeIf(ne, instr, scratch1, Operand(zero_reg));
+      DeoptimizeIf(ne, instr, "minus zero", scratch1, Operand(zero_reg));
       __ bind(&done);
     }
   }
 }
 
 
 void LCodeGen::DoDoubleToSmi(LDoubleToSmi* instr) {
   Register result_reg = ToRegister(instr->result());
   Register scratch1 = LCodeGen::scratch0();
   DoubleRegister double_input = ToDoubleRegister(instr->value());
 
   if (instr->truncating()) {
     __ TruncateDoubleToI(result_reg, double_input);
   } else {
     Register except_flag = LCodeGen::scratch1();
 
     __ EmitFPUTruncate(kRoundToMinusInf,
                        result_reg,
                        double_input,
                        scratch1,
                        double_scratch0(),
                        except_flag,
                        kCheckForInexactConversion);
 
     // Deopt if the operation did not succeed (except_flag != 0).
-    DeoptimizeIf(ne, instr, except_flag, Operand(zero_reg));
+    DeoptimizeIf(ne, instr, "lost precision or NaN", except_flag,
+                 Operand(zero_reg));
 
     if (instr->hydrogen()->CheckFlag(HValue::kBailoutOnMinusZero)) {
       Label done;
       __ Branch(&done, ne, result_reg, Operand(zero_reg));
       __ Mfhc1(scratch1, double_input);
       __ And(scratch1, scratch1, Operand(HeapNumber::kSignMask));
-      DeoptimizeIf(ne, instr, scratch1, Operand(zero_reg));
+      DeoptimizeIf(ne, instr, "minus zero", scratch1, Operand(zero_reg));
       __ bind(&done);
     }
   }
   __ SmiTagCheckOverflow(result_reg, result_reg, scratch1);
-  DeoptimizeIf(lt, instr, scratch1, Operand(zero_reg));
+  DeoptimizeIf(lt, instr, "overflow", scratch1, Operand(zero_reg));
 }
 
 
 void LCodeGen::DoCheckSmi(LCheckSmi* instr) {
   LOperand* input = instr->value();
   __ SmiTst(ToRegister(input), at);
-  DeoptimizeIf(ne, instr, at, Operand(zero_reg));
+  DeoptimizeIf(ne, instr, "not a Smi", at, Operand(zero_reg));
 }
 
 
 void LCodeGen::DoCheckNonSmi(LCheckNonSmi* instr) {
   if (!instr->hydrogen()->value()->type().IsHeapObject()) {
     LOperand* input = instr->value();
     __ SmiTst(ToRegister(input), at);
-    DeoptimizeIf(eq, instr, at, Operand(zero_reg));
+    DeoptimizeIf(eq, instr, "Smi", at, Operand(zero_reg));
   }
 }
 
 
 void LCodeGen::DoCheckInstanceType(LCheckInstanceType* instr) {
   Register input = ToRegister(instr->value());
   Register scratch = scratch0();
 
   __ GetObjectType(input, scratch, scratch);
 
   if (instr->hydrogen()->is_interval_check()) {
     InstanceType first;
     InstanceType last;
     instr->hydrogen()->GetCheckInterval(&first, &last);
 
     // If there is only one type in the interval check for equality.
     if (first == last) {
-      DeoptimizeIf(ne, instr, scratch, Operand(first));
+      DeoptimizeIf(ne, instr, "wrong instance type", scratch, Operand(first));
     } else {
-      DeoptimizeIf(lo, instr, scratch, Operand(first));
+      DeoptimizeIf(lo, instr, "wrong instance type", scratch, Operand(first));
       // Omit check for the last type.
       if (last != LAST_TYPE) {
-        DeoptimizeIf(hi, instr, scratch, Operand(last));
+        DeoptimizeIf(hi, instr, "wrong instance type", scratch, Operand(last));
       }
     }
   } else {
     uint8_t mask;
     uint8_t tag;
     instr->hydrogen()->GetCheckMaskAndTag(&mask, &tag);
 
     if (base::bits::IsPowerOfTwo32(mask)) {
       DCHECK(tag == 0 || base::bits::IsPowerOfTwo32(tag));
       __ And(at, scratch, mask);
-      DeoptimizeIf(tag == 0 ? ne : eq, instr, at, Operand(zero_reg));
+      DeoptimizeIf(tag == 0 ? ne : eq, instr, "wrong instance type", at,
+                   Operand(zero_reg));
     } else {
       __ And(scratch, scratch, Operand(mask));
-      DeoptimizeIf(ne, instr, scratch, Operand(tag));
+      DeoptimizeIf(ne, instr, "wrong instance type", scratch, Operand(tag));
     }
   }
 }
 
 
 void LCodeGen::DoCheckValue(LCheckValue* instr) {
   Register reg = ToRegister(instr->value());
   Handle<HeapObject> object = instr->hydrogen()->object().handle();
   AllowDeferredHandleDereference smi_check;
   if (isolate()->heap()->InNewSpace(*object)) {
     Register reg = ToRegister(instr->value());
     Handle<Cell> cell = isolate()->factory()->NewCell(object);
     __ li(at, Operand(Handle<Object>(cell)));
     __ lw(at, FieldMemOperand(at, Cell::kValueOffset));
-    DeoptimizeIf(ne, instr, reg, Operand(at));
+    DeoptimizeIf(ne, instr, "value mismatch", reg, Operand(at));
   } else {
-    DeoptimizeIf(ne, instr, reg, Operand(object));
+    DeoptimizeIf(ne, instr, "value mismatch", reg, Operand(object));
   }
 }
 
 
 void LCodeGen::DoDeferredInstanceMigration(LCheckMaps* instr, Register object) {
   {
     PushSafepointRegistersScope scope(this);
     __ push(object);
     __ mov(cp, zero_reg);
     __ CallRuntimeSaveDoubles(Runtime::kTryMigrateInstance);
     RecordSafepointWithRegisters(
         instr->pointer_map(), 1, Safepoint::kNoLazyDeopt);
     __ StoreToSafepointRegisterSlot(v0, scratch0());
   }
   __ SmiTst(scratch0(), at);
-  DeoptimizeIf(eq, instr, at, Operand(zero_reg));
+  DeoptimizeIf(eq, instr, "instance migration failed", at, Operand(zero_reg));
 }
 
 
 void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
   class DeferredCheckMaps FINAL : public LDeferredCode {
    public:
     DeferredCheckMaps(LCodeGen* codegen, LCheckMaps* instr, Register object)
         : LDeferredCode(codegen), instr_(instr), object_(object) {
       SetExit(check_maps());
     }
@@ skipping 32 matching lines @@
   Label success;
   for (int i = 0; i < maps->size() - 1; i++) {
     Handle<Map> map = maps->at(i).handle();
     __ CompareMapAndBranch(map_reg, map, &success, eq, &success);
   }
   Handle<Map> map = maps->at(maps->size() - 1).handle();
   // Do the CompareMap() directly within the Branch() and DeoptimizeIf().
   if (instr->hydrogen()->HasMigrationTarget()) {
     __ Branch(deferred->entry(), ne, map_reg, Operand(map));
   } else {
-    DeoptimizeIf(ne, instr, map_reg, Operand(map));
+    DeoptimizeIf(ne, instr, "wrong map", map_reg, Operand(map));
   }
 
   __ bind(&success);
 }
 
 
 void LCodeGen::DoClampDToUint8(LClampDToUint8* instr) {
   DoubleRegister value_reg = ToDoubleRegister(instr->unclamped());
   Register result_reg = ToRegister(instr->result());
   DoubleRegister temp_reg = ToDoubleRegister(instr->temp());
@@ skipping 17 matching lines @@
 
   // Both smi and heap number cases are handled.
   __ UntagAndJumpIfSmi(scratch, input_reg, &is_smi);
 
   // Check for heap number
   __ lw(scratch, FieldMemOperand(input_reg, HeapObject::kMapOffset));
   __ Branch(&heap_number, eq, scratch, Operand(factory()->heap_number_map()));
 
   // Check for undefined. Undefined is converted to zero for clamping
   // conversions.
-  DeoptimizeIf(ne, instr, input_reg, Operand(factory()->undefined_value()));
+  DeoptimizeIf(ne, instr, "not a heap number/undefined", input_reg,
+               Operand(factory()->undefined_value()));
   __ mov(result_reg, zero_reg);
   __ jmp(&done);
 
   // Heap number
   __ bind(&heap_number);
   __ ldc1(double_scratch0(), FieldMemOperand(input_reg,
                                              HeapNumber::kValueOffset));
   __ ClampDoubleToUint8(result_reg, double_scratch0(), temp_reg);
   __ jmp(&done);
 
@@ skipping 402 matching lines @@
 void LCodeGen::DoDeoptimize(LDeoptimize* instr) {
   Deoptimizer::BailoutType type = instr->hydrogen()->type();
   // TODO(danno): Stubs expect all deopts to be lazy for historical reasons (the
   // needed return address), even though the implementation of LAZY and EAGER is
   // now identical. When LAZY is eventually completely folded into EAGER, remove
   // the special case below.
   if (info()->IsStub() && type == Deoptimizer::EAGER) {
     type = Deoptimizer::LAZY;
   }
 
-  DeoptimizeIf(al, instr, type, zero_reg, Operand(zero_reg),
-               instr->hydrogen()->reason());
+  DeoptimizeIf(al, instr, type, instr->hydrogen()->reason(), zero_reg,
+               Operand(zero_reg));
 }
 
 
 void LCodeGen::DoDummy(LDummy* instr) {
   // Nothing to see here, move on!
 }
 
 
 void LCodeGen::DoDummyUse(LDummyUse* instr) {
   // Nothing to see here, move on!
@@ skipping 70 matching lines @@
   RegisterEnvironmentForDeoptimization(environment, Safepoint::kNoLazyDeopt);
 
   GenerateOsrPrologue();
 }
 
 
 void LCodeGen::DoForInPrepareMap(LForInPrepareMap* instr) {
   Register result = ToRegister(instr->result());
   Register object = ToRegister(instr->object());
   __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
-  DeoptimizeIf(eq, instr, object, Operand(at));
+  DeoptimizeIf(eq, instr, "undefined", object, Operand(at));
 
   Register null_value = t1;
   __ LoadRoot(null_value, Heap::kNullValueRootIndex);
-  DeoptimizeIf(eq, instr, object, Operand(null_value));
+  DeoptimizeIf(eq, instr, "null", object, Operand(null_value));
 
   __ And(at, object, kSmiTagMask);
-  DeoptimizeIf(eq, instr, at, Operand(zero_reg));
+  DeoptimizeIf(eq, instr, "Smi", at, Operand(zero_reg));
 
   STATIC_ASSERT(FIRST_JS_PROXY_TYPE == FIRST_SPEC_OBJECT_TYPE);
   __ GetObjectType(object, a1, a1);
-  DeoptimizeIf(le, instr, a1, Operand(LAST_JS_PROXY_TYPE));
+  DeoptimizeIf(le, instr, "not a JavaScript object", a1,
+               Operand(LAST_JS_PROXY_TYPE));
 
   Label use_cache, call_runtime;
   DCHECK(object.is(a0));
   __ CheckEnumCache(null_value, &call_runtime);
 
   __ lw(result, FieldMemOperand(object, HeapObject::kMapOffset));
   __ Branch(&use_cache);
 
   // Get the set of properties to enumerate.
   __ bind(&call_runtime);
   __ push(object);
   CallRuntime(Runtime::kGetPropertyNamesFast, 1, instr);
 
   __ lw(a1, FieldMemOperand(v0, HeapObject::kMapOffset));
   DCHECK(result.is(v0));
   __ LoadRoot(at, Heap::kMetaMapRootIndex);
-  DeoptimizeIf(ne, instr, a1, Operand(at));
+  DeoptimizeIf(ne, instr, "wrong map", a1, Operand(at));
   __ bind(&use_cache);
 }
 
 
 void LCodeGen::DoForInCacheArray(LForInCacheArray* instr) {
   Register map = ToRegister(instr->map());
   Register result = ToRegister(instr->result());
   Label load_cache, done;
   __ EnumLength(result, map);
   __ Branch(&load_cache, ne, result, Operand(Smi::FromInt(0)));
   __ li(result, Operand(isolate()->factory()->empty_fixed_array()));
   __ jmp(&done);
 
   __ bind(&load_cache);
   __ LoadInstanceDescriptors(map, result);
   __ lw(result,
         FieldMemOperand(result, DescriptorArray::kEnumCacheOffset));
   __ lw(result,
         FieldMemOperand(result, FixedArray::SizeFor(instr->idx())));
-  DeoptimizeIf(eq, instr, result, Operand(zero_reg));
+  DeoptimizeIf(eq, instr, "no cache", result, Operand(zero_reg));
 
   __ bind(&done);
 }
 
 
 void LCodeGen::DoCheckMapValue(LCheckMapValue* instr) {
   Register object = ToRegister(instr->value());
   Register map = ToRegister(instr->map());
   __ lw(scratch0(), FieldMemOperand(object, HeapObject::kMapOffset));
-  DeoptimizeIf(ne, instr, map, Operand(scratch0()));
+  DeoptimizeIf(ne, instr, "wrong map", map, Operand(scratch0()));
 }
 
 
 void LCodeGen::DoDeferredLoadMutableDouble(LLoadFieldByIndex* instr,
                                            Register result,
                                            Register object,
                                            Register index) {
   PushSafepointRegistersScope scope(this);
   __ Push(object, index);
   __ mov(cp, zero_reg);
@@ skipping 75 matching lines @@
   __ li(at, scope_info);
   __ Push(at, ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal