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

src/compiler/simplified-operator.cc

Index: src/compiler/simplified-operator.cc
diff --git a/src/compiler/simplified-operator.cc b/src/compiler/simplified-operator.cc
index 258f4c324bed440619d14ffbea9e2cf0ce07d4e4..ac5134d7588598968f22ecba895013456bb3c092 100644
--- a/src/compiler/simplified-operator.cc
+++ b/src/compiler/simplified-operator.cc
@@ -201,6 +201,26 @@ CheckFloat64HoleMode CheckFloat64HoleModeOf(const Operator* op) {
   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);
 }
@@ -334,7 +354,6 @@ CompareOperationHints::Hint CompareOperationHintOf(const Operator* op) {
   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)  \
@@ -362,6 +381,20 @@ struct SimplifiedOperatorGlobalCache final {
   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> {
@@ -441,6 +474,18 @@ PURE_OP_LIST(GET_FROM_CACHE)
 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) {