[PATCH] D49596: [Support] Add a UniqueStringSaver: like StringSaver, but deduplicating.

[Haojian Wu via Phabricator via llvm-commits]

hokein added a comment.

Thanks!



================
Comment at: lib/Support/StringSaver.cpp:26
+  S = Strings.save(S);
+  if (!Unique.insert(S).second)
+    llvm_unreachable("Failed to insert into unique table - race?");
----------------
While we have nice assertion message here, but in return we pay an extra lookup cost. I think we should avoid it (this function is likely to be used in hot path).

Maybe just

```
auto It = Unique.insert(S);
if (It.second) {
  *It.first = Strings.save(V);
}
return *It.first.
```


Repository:
  rL LLVM

https://reviews.llvm.org/D49596