diff --git a/src/libpmr/allocator.cpp b/src/libpmr/allocator.cpp
index 68eb9fc4..4f91848e 100644
--- a/src/libpmr/allocator.cpp
+++ b/src/libpmr/allocator.cpp
@@ -1,6 +1,7 @@
 
 #include <algorithm>  // std::swap
 
+#include "libimp/log.h"
 #include "libpmr/allocator.h"
 
 LIBPMR_NAMESPACE_BEG_
@@ -25,10 +26,20 @@ void allocator::swap(allocator &other) noexcept {
 }
 
 void *allocator::allocate(std::size_t s, std::size_t a) const {
+  LIBIMP_LOG_();
+  if ((a & (a - 1)) != 0) {
+    log.error("failed: allocate alignment is not a power of 2.");
+    return nullptr;
+  }
   return get_holder().alloc(s, a);
 }
 
 void allocator::deallocate(void *p, std::size_t s, std::size_t a) const {
+  LIBIMP_LOG_();
+  if ((a & (a - 1)) != 0) {
+    log.error("failed: allocate alignment is not a power of 2.");
+    return;
+  }
   get_holder().dealloc(p, s, a);
 }
 
diff --git a/src/libpmr/monotonic_buffer_resource.cpp b/src/libpmr/monotonic_buffer_resource.cpp
index 7f2efddc..f43d7237 100644
--- a/src/libpmr/monotonic_buffer_resource.cpp
+++ b/src/libpmr/monotonic_buffer_resource.cpp
@@ -92,10 +92,6 @@ void *monotonic_buffer_resource::allocate(std::size_t bytes, std::size_t alignme
     log.error("failed: allocate bytes = 0.");
     return nullptr;
   }
-  if ((alignment & (alignment - 1)) != 0) {
-    log.error("failed: allocate alignment is not a power of 2.");
-    return nullptr;
-  }
   void *p = head_;
   auto  s = static_cast<std::size_t>(tail_ - head_);
   if (std::align(alignment, bytes, p, s) == nullptr) {
diff --git a/test/pmr/test_pmr_memory_resource.cpp b/test/pmr/test_pmr_memory_resource.cpp
index f90e4d3b..b624135b 100644
--- a/test/pmr/test_pmr_memory_resource.cpp
+++ b/test/pmr/test_pmr_memory_resource.cpp
@@ -28,7 +28,7 @@ TEST(memory_resource, traits) {
   EXPECT_FALSE(pmr::has_allocate<void>::value);
   EXPECT_FALSE(pmr::has_allocate<int>::value);
   EXPECT_FALSE(pmr::has_allocate<std::vector<int>>::value);
-  EXPECT_TRUE (pmr::has_allocate<std::allocator<int>>::value);
+  EXPECT_FALSE(pmr::has_allocate<std::allocator<int>>::value);
 #if defined(LIBIMP_CPP_17) && defined(__cpp_lib_memory_resource)
   EXPECT_TRUE (pmr::has_allocate<std::pmr::memory_resource>::value);
   EXPECT_TRUE (pmr::has_allocate<std::pmr::polymorphic_allocator<int>>::value);
diff --git a/test/pmr/test_pmr_monotonic_buffer_resource.cpp b/test/pmr/test_pmr_monotonic_buffer_resource.cpp
index fc0bdd5c..a4fe77aa 100644
--- a/test/pmr/test_pmr_monotonic_buffer_resource.cpp
+++ b/test/pmr/test_pmr_monotonic_buffer_resource.cpp
@@ -102,13 +102,13 @@ TEST(monotonic_buffer_resource, release) {
     tmp.release();
     ASSERT_EQ(dummy.allocated, 0);
     ASSERT_NE(tmp.allocate(1024), nullptr);
-    ASSERT_GE(dummy.allocated, 1024);
-    ASSERT_LE(dummy.allocated, 1024 * 1.5);
+    ASSERT_GE(dummy.allocated, 1024u);
+    ASSERT_LE(dummy.allocated, 1024u * 1.5);
     tmp.release();
     ASSERT_EQ(dummy.allocated, 0);
     ASSERT_NE(tmp.allocate(1024), nullptr);
-    ASSERT_GE(dummy.allocated, 1024);
-    ASSERT_LE(dummy.allocated, 1024 * 1.5);
+    ASSERT_GE(dummy.allocated, 1024u);
+    ASSERT_LE(dummy.allocated, 1024u * 1.5);
   }
   ASSERT_EQ(dummy.allocated, 0);
   std::array<imp::byte, 4096> buffer;
@@ -119,7 +119,7 @@ TEST(monotonic_buffer_resource, release) {
     ASSERT_EQ(dummy.allocated, 0);
     p = tmp.allocate(10240);
     ASSERT_NE(p, buffer.data());
-    ASSERT_LE(dummy.allocated, 10240 + 1024);
+    ASSERT_LE(dummy.allocated, 10240u + 1024u);
     tmp.release();
     ASSERT_EQ(dummy.allocated, 0);
     p = tmp.allocate(1024);
@@ -127,7 +127,7 @@ TEST(monotonic_buffer_resource, release) {
     ASSERT_EQ(dummy.allocated, 0);
     p = tmp.allocate(10240);
     ASSERT_NE(p, buffer.data());
-    ASSERT_LE(dummy.allocated, 10240 + 1024);
+    ASSERT_LE(dummy.allocated, 10240u + 1024u);
   }
   ASSERT_EQ(dummy.allocated, 0);
 }