[turbofan] Let ChangeFloat64ToTagged canonicalize to Smi if possible.

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 e8e21bf59cff433270321c3e01ee78f1d3afae0f..9fb0fc55bf953f0cd6aef3bb1139ee4671ce99b6 100644
--- a/src/compiler/simplified-operator.cc
+++ b/src/compiler/simplified-operator.cc
@@ -213,7 +213,8 @@ CheckFloat64HoleMode CheckFloat64HoleModeOf(const Operator* op) {
 }
 
 CheckForMinusZeroMode CheckMinusZeroModeOf(const Operator* op) {
-  DCHECK(op->opcode() == IrOpcode::kCheckedInt32Mul ||
+  DCHECK(op->opcode() == IrOpcode::kChangeFloat64ToTagged ||
+         op->opcode() == IrOpcode::kCheckedInt32Mul ||
          op->opcode() == IrOpcode::kCheckedFloat64ToInt32 ||
          op->opcode() == IrOpcode::kCheckedTaggedToInt32);
   return OpParameter<CheckForMinusZeroMode>(op);
@@ -488,7 +489,6 @@ UnicodeEncoding UnicodeEncodingOf(const Operator* op) {
   V(ChangeTaggedToUint32, Operator::kNoProperties, 1, 0)         \
   V(ChangeTaggedToFloat64, Operator::kNoProperties, 1, 0)        \
   V(ChangeTaggedToTaggedSigned, Operator::kNoProperties, 1, 0)   \
-  V(ChangeFloat64ToTagged, Operator::kNoProperties, 1, 0)        \
   V(ChangeFloat64ToTaggedPointer, Operator::kNoProperties, 1, 0) \
   V(ChangeInt31ToTaggedSigned, Operator::kNoProperties, 1, 0)    \
   V(ChangeInt32ToTagged, Operator::kNoProperties, 1, 0)          \
@@ -601,6 +601,19 @@ struct SimplifiedOperatorGlobalCache final {
   NewUnmappedArgumentsElementsOperator kNewUnmappedArgumentsElements;
 
   template <CheckForMinusZeroMode kMode>
+  struct ChangeFloat64ToTaggedOperator final
+      : public Operator1<CheckForMinusZeroMode> {
+    ChangeFloat64ToTaggedOperator()
+        : Operator1<CheckForMinusZeroMode>(
+              IrOpcode::kChangeFloat64ToTagged, Operator::kPure,
+              "ChangeFloat64ToTagged", 1, 0, 0, 1, 0, 0, kMode) {}
+  };
+  ChangeFloat64ToTaggedOperator<CheckForMinusZeroMode::kCheckForMinusZero>
+      kChangeFloat64ToTaggedCheckForMinusZeroOperator;
+  ChangeFloat64ToTaggedOperator<CheckForMinusZeroMode::kDontCheckForMinusZero>
+      kChangeFloat64ToTaggedDontCheckForMinusZeroOperator;
+
+  template <CheckForMinusZeroMode kMode>
   struct CheckedInt32MulOperator final
       : public Operator1<CheckForMinusZeroMode> {
     CheckedInt32MulOperator()
@@ -757,6 +770,18 @@ GET_FROM_CACHE(ArgumentsFrame)
 GET_FROM_CACHE(NewUnmappedArgumentsElements)
 #undef GET_FROM_CACHE
 
+const Operator* SimplifiedOperatorBuilder::ChangeFloat64ToTagged(
+    CheckForMinusZeroMode mode) {
+  switch (mode) {
+    case CheckForMinusZeroMode::kCheckForMinusZero:
+      return &cache_.kChangeFloat64ToTaggedCheckForMinusZeroOperator;
+    case CheckForMinusZeroMode::kDontCheckForMinusZero:
+      return &cache_.kChangeFloat64ToTaggedDontCheckForMinusZeroOperator;
+  }
+  UNREACHABLE();
+  return nullptr;
+}
+
 const Operator* SimplifiedOperatorBuilder::CheckedInt32Mul(
     CheckForMinusZeroMode mode) {
   switch (mode) {