[intrinsics] Kill the %_IsMinusZero intrinsic.

src/crankshaft/hydrogen-instructions.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/crankshaft/hydrogen-instructions.h"
 
 #include "src/base/bits.h"
 #include "src/base/safe_math.h"
 #include "src/crankshaft/hydrogen-infer-representation.h"
 #include "src/double.h"
@@ skipping 765 matching lines @@
     case HValue::kBlockEntry:
     case HValue::kBoundsCheckBaseIndexInformation:
     case HValue::kCallFunction:
     case HValue::kCallNewArray:
     case HValue::kCallStub:
     case HValue::kCapturedObject:
     case HValue::kClassOfTestAndBranch:
     case HValue::kCompareGeneric:
     case HValue::kCompareHoleAndBranch:
     case HValue::kCompareMap:
-    case HValue::kCompareMinusZeroAndBranch:
     case HValue::kCompareNumericAndBranch:
     case HValue::kCompareObjectEqAndBranch:
     case HValue::kConstant:
     case HValue::kConstructDouble:
     case HValue::kContext:
     case HValue::kDebugBreak:
     case HValue::kDeclareGlobals:
     case HValue::kDoubleBits:
     case HValue::kDummyUse:
     case HValue::kEnterInlined:
@@ skipping 2522 matching lines @@
               token() == Token::LTE ||
               token() == Token::GTE)
         ? FirstSuccessor() : SecondSuccessor();
     return true;
   }
   *block = NULL;
   return false;
 }
 
 
-bool HCompareMinusZeroAndBranch::KnownSuccessorBlock(HBasicBlock** block) {
-  if (FLAG_fold_constants && value()->IsConstant()) {
-    HConstant* constant = HConstant::cast(value());
-    if (constant->HasDoubleValue()) {
-      *block = IsMinusZero(constant->DoubleValue())
-          ? FirstSuccessor() : SecondSuccessor();
-      return true;
-    }
-  }
-  if (value()->representation().IsSmiOrInteger32()) {
-    // A Smi or Integer32 cannot contain minus zero.
-    *block = SecondSuccessor();
-    return true;
-  }
-  *block = NULL;
-  return false;
-}
-
-
-void HCompareMinusZeroAndBranch::InferRepresentation(
-    HInferRepresentationPhase* h_infer) {
-  ChangeRepresentation(value()->representation());
-}
-
-
 std::ostream& HGoto::PrintDataTo(std::ostream& os) const {  // NOLINT
   return os << *SuccessorAt(0);
 }
 
 
 void HCompareNumericAndBranch::InferRepresentation(
     HInferRepresentationPhase* h_infer) {
   Representation left_rep = left()->representation();
   Representation right_rep = right()->representation();
   Representation observed_left = observed_input_representation(0);
@@ skipping 1328 matching lines @@
     case HObjectAccess::kExternalMemory:
       os << "[external-memory]";
       break;
   }
 
   return os << "@" << access.offset();
 }
 
 }  // namespace internal
 }  // namespace v8