Do not remove HAdd with zero if the other operand is a double.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 6da6774aa8e87302bdd2a03a9f4f31f88d8216e7..206ab7e2accf5e496b6cd814eb1071c511cb21e7 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -1255,8 +1255,15 @@ static bool IsIdentityOperation(HValue* arg1, HValue* arg2, int32_t identity) {
 
 
 HValue* HAdd::Canonicalize() {
-  if (IsIdentityOperation(left(), right(), 0)) return left();
-  if (IsIdentityOperation(right(), left(), 0)) return right();
+  // Adding 0 is an identity operation except in case of -0: -0 + 0 = +0
+  if (IsIdentityOperation(left(), right(), 0) &&
+      !left()->representation().IsDouble()) {  // Left could be -0.
+    return left();
+  }
+  if (IsIdentityOperation(right(), left(), 0) &&
+      !left()->representation().IsDouble()) {  // Right could be -0.
+    return right();
+  }
   return this;
 }