[turbofan] Let ChangeFloat64ToTagged canonicalize to Smi if possible.

src/compiler/effect-control-linearizer.cc

Index: src/compiler/effect-control-linearizer.cc
diff --git a/src/compiler/effect-control-linearizer.cc b/src/compiler/effect-control-linearizer.cc
index 245dbd07c7c03ff9a219ee3d8b725d902f713162..0e48932c8dd2157538a1691ed55f259b039731a8 100644
--- a/src/compiler/effect-control-linearizer.cc
+++ b/src/compiler/effect-control-linearizer.cc
@@ -829,8 +829,62 @@ bool EffectControlLinearizer::TryWireInStateEffect(Node* node,
 #define __ gasm()->
 
 Node* EffectControlLinearizer::LowerChangeFloat64ToTagged(Node* node) {
+  CheckForMinusZeroMode mode = CheckMinusZeroModeOf(node->op());
   Node* value = node->InputAt(0);
-  return AllocateHeapNumberWithValue(value);
+
+  auto done = __ MakeLabel<2>(MachineRepresentation::kTagged);
+  auto if_heapnumber =
+      __ MakeLabelFor(GraphAssemblerLabelType::kNonDeferred,
+                      1 + (mode == CheckForMinusZeroMode::kCheckForMinusZero) +
+                          !machine()->Is64());
+  auto if_int32 = __ MakeLabel<1>();
+
+  Node* value32 = __ RoundFloat64ToInt32(value);
+  __ GotoIf(__ Float64Equal(value, __ ChangeInt32ToFloat64(value32)),
+            &if_int32);
+  __ Goto(&if_heapnumber);
+
+  __ Bind(&if_int32);
+  {
+    if (mode == CheckForMinusZeroMode::kCheckForMinusZero) {
+      Node* zero = __ Int32Constant(0);
+      auto if_zero = __ MakeDeferredLabel<1>();
+      auto if_smi = __ MakeLabel<2>();
+
+      __ GotoIf(__ Word32Equal(value32, zero), &if_zero);
+      __ Goto(&if_smi);
+
+      __ Bind(&if_zero);
+      {
+        // In case of 0, we need to check the high bits for the IEEE -0 pattern.
+        __ GotoIf(__ Int32LessThan(__ Float64ExtractHighWord32(value), zero),
+                  &if_heapnumber);
+        __ Goto(&if_smi);
+      }
+
+      __ Bind(&if_smi);
+    }
+
+    if (machine()->Is64()) {
+      Node* value_smi = ChangeInt32ToSmi(value32);
+      __ Goto(&done, value_smi);
+    } else {
+      Node* add = __ Int32AddWithOverflow(value32, value32);
+      Node* ovf = __ Projection(1, add);
+      __ GotoIf(ovf, &if_heapnumber);
+      Node* value_smi = __ Projection(0, add);
+      __ Goto(&done, value_smi);
+    }
+  }
+
+  __ Bind(&if_heapnumber);
+  {
+    Node* value_number = AllocateHeapNumberWithValue(value);
+    __ Goto(&done, value_number);
+  }
+
+  __ Bind(&done);
+  return done.PhiAt(0);
 }
 
 Node* EffectControlLinearizer::LowerChangeFloat64ToTaggedPointer(Node* node) {