[PATCH] D47344: LWG 2843 "Unclear behavior of std::pmr::memory_resource::do_allocate()"

[Eric Fiselier via Phabricator via cfe-commits]

EricWF requested changes to this revision.
EricWF added a comment.
This revision now requires changes to proceed.

Actually, I spotted a couple of issues. Requesting changes.



================
Comment at: src/experimental/memory_resource.cpp:29
+static bool is_aligned_to(void *ptr, size_t align)
+{
+    void *p2 = ptr;
----------------
Wait, can't this be written `reinterpret_cast<uintptr_t>(ptr) % align == 0`?


================
Comment at: src/experimental/memory_resource.cpp:48
+#ifdef _LIBCPP_HAS_NO_ALIGNED_ALLOCATION
+        if (__size != 0 && !is_aligned_to(result, __align)) {
+            _VSTD::__libcpp_deallocate(result, __align);
----------------
Also, I'm not sure about the `size != 0` check. The returned pointer may be non-null and incorrectly aligned.


Repository:
  rCXX libc++

https://reviews.llvm.org/D47344