Speed up `raw_hash_map::[]` with ABSL hardening enabled by unchecking dereference of iterator returned by `try_emplace`.

PiperOrigin-RevId: 597920257
Change-Id: I1b2e8f10a2f1efa763a6f0760294beafdb6fd9c0

1 files changed, 7 insertions, 1 deletions

diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h
index b6dc7548..3518bc34 100644
--- a/absl/container/internal/raw_hash_set.h
+++ b/absl/container/internal/raw_hash_set.h
@@ -1943,7 +1943,7 @@ class raw_hash_set {
     // PRECONDITION: not an end() iterator.
     reference operator*() const {
       AssertIsFull(ctrl_, generation(), generation_ptr(), "operator*()");
-      return PolicyTraits::element(slot_);
+      return unchecked_deref();
     }
 
     // PRECONDITION: not an end() iterator.
@@ -2023,6 +2023,10 @@ class raw_hash_set {
     // Should be used when the lifetimes of the iterators are well-enough
     // understood to prove that they cannot be invalid.
     bool unchecked_equals(const iterator& b) { return ctrl_ == b.control(); }
+
+    // Dereferences the iterator without ABSL Hardening iterator invalidation
+    // checks.
+    reference unchecked_deref() const { return PolicyTraits::element(slot_); }
   };
 
   class const_iterator {
@@ -3159,6 +3163,8 @@ class raw_hash_set {
     return {control() + i, slot_array() + i, common().generation_ptr()};
   }
 
+  reference unchecked_deref(iterator it) { return it.unchecked_deref(); }
+
  private:
   friend struct RawHashSetTestOnlyAccess;