[Turbofan]: Eliminate the check for -0 if it's not possible/observable.

src/compiler/simplified-operator.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/compiler/simplified-operator.h"
 
 #include "src/base/lazy-instance.h"
 #include "src/compiler/opcodes.h"
 #include "src/compiler/operator.h"
 #include "src/types.h"
@@ skipping 183 matching lines @@
   }
   UNREACHABLE();
   return os;
 }
 
 CheckFloat64HoleMode CheckFloat64HoleModeOf(const Operator* op) {
   DCHECK_EQ(IrOpcode::kCheckFloat64Hole, op->opcode());
   return OpParameter<CheckFloat64HoleMode>(op);
 }
 
+CheckForMinusZeroMode CheckMinusZeroModeOf(const Operator* op) {
+  DCHECK_EQ(IrOpcode::kCheckedInt32Mul, op->opcode());
+  return OpParameter<CheckForMinusZeroMode>(op);
+}
+
+size_t hash_value(CheckForMinusZeroMode mode) {
+  return static_cast<size_t>(mode);
+}
+
+std::ostream& operator<<(std::ostream& os, CheckForMinusZeroMode mode) {
+  switch (mode) {
+    case CheckForMinusZeroMode::kCheckForMinusZero:
+      return os << "check-for-minus-zero";
+    case CheckForMinusZeroMode::kDontCheckForMinusZero:
+      return os << "dont-check-for-minus-zero";
+  }
+  UNREACHABLE();
+  return os;
+}
+
 size_t hash_value(CheckTaggedHoleMode mode) {
   return static_cast<size_t>(mode);
 }
 
 std::ostream& operator<<(std::ostream& os, CheckTaggedHoleMode mode) {
   switch (mode) {
     case CheckTaggedHoleMode::kConvertHoleToUndefined:
       return os << "convert-hole-to-undefined";
     case CheckTaggedHoleMode::kNeverReturnHole:
       return os << "never-return-hole";
@@ skipping 113 matching lines @@
   V(CheckIf, 1, 0)               \
   V(CheckNumber, 1, 1)           \
   V(CheckTaggedPointer, 1, 1)    \
   V(CheckTaggedSigned, 1, 1)     \
   V(CheckedInt32Add, 2, 1)       \
   V(CheckedInt32Sub, 2, 1)       \
   V(CheckedInt32Div, 2, 1)       \
   V(CheckedInt32Mod, 2, 1)       \
   V(CheckedUint32Div, 2, 1)      \
   V(CheckedUint32Mod, 2, 1)      \
-  V(CheckedInt32Mul, 2, 1)       \
   V(CheckedUint32ToInt32, 1, 1)  \
   V(CheckedFloat64ToInt32, 1, 1) \
   V(CheckedTaggedToInt32, 1, 1)  \
   V(CheckedTaggedToFloat64, 1, 1)
 
 struct SimplifiedOperatorGlobalCache final {
 #define PURE(Name, properties, input_count)                                \
   struct Name##Operator final : public Operator {                          \
     Name##Operator()                                                       \
         : Operator(IrOpcode::k##Name, Operator::kPure | properties, #Name, \
                    input_count, 0, 0, 1, 0, 0) {}                          \
   };                                                                       \
   Name##Operator k##Name;
   PURE_OP_LIST(PURE)
 #undef PURE
 
 #define CHECKED(Name, value_input_count, value_output_count)             \
   struct Name##Operator final : public Operator {                        \
     Name##Operator()                                                     \
         : Operator(IrOpcode::k##Name,                                    \
                    Operator::kFoldable | Operator::kNoThrow, #Name,      \
                    value_input_count, 1, 1, value_output_count, 1, 0) {} \
   };                                                                     \
   Name##Operator k##Name;
   CHECKED_OP_LIST(CHECKED)
 #undef CHECKED
 
+  template <CheckForMinusZeroMode kMode>
+  struct CheckedInt32MulOperator final
+      : public Operator1<CheckForMinusZeroMode> {
+    CheckedInt32MulOperator()
+        : Operator1<CheckForMinusZeroMode>(
+              IrOpcode::kCheckedInt32Mul,
+              Operator::kFoldable | Operator::kNoThrow, "CheckedInt32Mul", 2, 1,
+              1, 1, 1, 0, kMode) {}
+  };
+  CheckedInt32MulOperator<CheckForMinusZeroMode::kCheckForMinusZero>
+      kCheckedInt32MulCheckForMinusZeroOperator;
+  CheckedInt32MulOperator<CheckForMinusZeroMode::kDontCheckForMinusZero>
+      kCheckedInt32MulDontCheckForMinusZeroOperator;
+
   template <CheckFloat64HoleMode kMode>
   struct CheckFloat64HoleNaNOperator final
       : public Operator1<CheckFloat64HoleMode> {
     CheckFloat64HoleNaNOperator()
         : Operator1<CheckFloat64HoleMode>(
               IrOpcode::kCheckFloat64Hole,
               Operator::kFoldable | Operator::kNoThrow, "CheckFloat64Hole", 1,
               1, 1, 1, 1, 0, kMode) {}
   };
   CheckFloat64HoleNaNOperator<CheckFloat64HoleMode::kAllowReturnHole>
@@ skipping 59 matching lines @@
 #define GET_FROM_CACHE(Name, properties, input_count) \
   const Operator* SimplifiedOperatorBuilder::Name() { return &cache_.k##Name; }
 PURE_OP_LIST(GET_FROM_CACHE)
 #undef GET_FROM_CACHE
 
 #define GET_FROM_CACHE(Name, value_input_count, value_output_count) \
   const Operator* SimplifiedOperatorBuilder::Name() { return &cache_.k##Name; }
 CHECKED_OP_LIST(GET_FROM_CACHE)
 #undef GET_FROM_CACHE
 
+const Operator* SimplifiedOperatorBuilder::CheckedInt32Mul(
+    CheckForMinusZeroMode mode) {
+  switch (mode) {
+    case CheckForMinusZeroMode::kCheckForMinusZero:
+      return &cache_.kCheckedInt32MulCheckForMinusZeroOperator;
+    case CheckForMinusZeroMode::kDontCheckForMinusZero:
+      return &cache_.kCheckedInt32MulDontCheckForMinusZeroOperator;
+  }
+  UNREACHABLE();
+  return nullptr;
+}
+
 const Operator* SimplifiedOperatorBuilder::CheckFloat64Hole(
     CheckFloat64HoleMode mode) {
   switch (mode) {
     case CheckFloat64HoleMode::kAllowReturnHole:
       return &cache_.kCheckFloat64HoleAllowReturnHoleOperator;
     case CheckFloat64HoleMode::kNeverReturnHole:
       return &cache_.kCheckFloat64HoleNeverReturnHoleOperator;
   }
   UNREACHABLE();
   return nullptr;
@@ skipping 102 matching lines @@
                         Operator::kNoDeopt | Operator::kNoThrow | properties,  \
                         #Name, value_input_count, 1, control_input_count,      \
                         output_count, 1, 0, access);                           \
   }
 ACCESS_OP_LIST(ACCESS)
 #undef ACCESS
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8