  We propose a novel notion of pointer race for concurrent programs
manipulating a shared heap. A pointer race is an access to a memory address
which was freed, and it is out of the accessor's control whether or not the
cell has been re-allocated. We establish two results. (1) Under the assumption
of pointer race freedom, it is sound to verify a program running under explicit
memory management as if it was running with garbage collection. (2) Even the
requirement of pointer race freedom itself can be verified under the
garbage-collected semantics. We then prove analogues of the theorems for a
stronger notion of pointer race needed to cope with performance-critical code
purposely using racy comparisons and even racy dereferences of pointers. As a
practical contribution, we apply our results to optimize a thread-modular
analysis under explicit memory management. Our experiments confirm a speed-up
of up to two orders of magnitude.
