From 1b14c69decc3a092c22fb1f6b2f93cadbf50855e Mon Sep 17 00:00:00 2001
From: "Agarwal, Udit" <udit.agarwal@intel.com>
Date: Mon, 19 Feb 2024 22:26:41 -0800
Subject: [PATCH 1/4] Return nullptr when allocation size is zero

---
 sycl/include/sycl/usm/usm_allocator.hpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sycl/include/sycl/usm/usm_allocator.hpp b/sycl/include/sycl/usm/usm_allocator.hpp
index 6ae1da5a3e350..31d9c5ec9a955 100644
--- a/sycl/include/sycl/usm/usm_allocator.hpp
+++ b/sycl/include/sycl/usm/usm_allocator.hpp
@@ -71,6 +71,9 @@ class usm_allocator {
   T *allocate(size_t NumberOfElements, const detail::code_location CodeLoc =
                                            detail::code_location::current()) {
 
+    if (!NumberOfElements)
+      return nullptr;
+
     auto Result = reinterpret_cast<T *>(
         aligned_alloc(getAlignment(), NumberOfElements * sizeof(value_type),
                       MDevice, MContext, AllocKind, MPropList, CodeLoc));

From 454156be5eb82bf54fc80949bab10722aac02f8c Mon Sep 17 00:00:00 2001
From: "Agarwal, Udit" <udit.agarwal@intel.com>
Date: Tue, 20 Feb 2024 09:03:55 -0800
Subject: [PATCH 2/4] Added test case

---
 .../USM/usm_allocator_zero_allocation.cpp     | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 sycl/test-e2e/USM/usm_allocator_zero_allocation.cpp

diff --git a/sycl/test-e2e/USM/usm_allocator_zero_allocation.cpp b/sycl/test-e2e/USM/usm_allocator_zero_allocation.cpp
new file mode 100644
index 0000000000000..fa54f25ccd32b
--- /dev/null
+++ b/sycl/test-e2e/USM/usm_allocator_zero_allocation.cpp
@@ -0,0 +1,25 @@
+// RUN: %{build} -o %t.out
+// RUN: %{run} %t.out
+
+#include <sycl/sycl.hpp>
+
+using namespace sycl;
+#define ALLOC_SIZE 0
+
+int main() {
+  queue q;
+  auto dev = q.get_device();
+  auto ctxt = q.get_context();
+
+  if (dev.get_info<info::device::usm_host_allocations>()) {
+    sycl::usm_allocator<int, sycl::usm::alloc::host> ua{ctxt, dev};
+    int *p = ua.allocate(ALLOC_SIZE);
+
+    assert(!p && "usm_allocator should return a null pointer when allocation "
+                 "size is zero.");
+
+    ua.deallocate(p, ALLOC_SIZE);
+  }
+
+  return 0;
+}

From 2145b66d5fff13ac4218fde5afb146c22797144c Mon Sep 17 00:00:00 2001
From: "Agarwal, Udit" <udit.agarwal@intel.com>
Date: Tue, 20 Feb 2024 12:53:44 -0800
Subject: [PATCH 3/4] Fix test case

---
 .../USM/usm_allocator_zero_allocation.cpp     | 24 ++++++++++++-------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/sycl/test-e2e/USM/usm_allocator_zero_allocation.cpp b/sycl/test-e2e/USM/usm_allocator_zero_allocation.cpp
index fa54f25ccd32b..3cda72a03f064 100644
--- a/sycl/test-e2e/USM/usm_allocator_zero_allocation.cpp
+++ b/sycl/test-e2e/USM/usm_allocator_zero_allocation.cpp
@@ -4,21 +4,27 @@
 #include <sycl/sycl.hpp>
 
 using namespace sycl;
-#define ALLOC_SIZE 0
+
+template <usm::alloc alloc_kind> void test(queue &q) {
+  sycl::usm_allocator<int, alloc_kind> ua(q);
+  int *p = ua.allocate(0);
+
+  assert(!p && "Our implementation of usm_allocator is expected to return a "
+               "null pointer when allocation "
+               "size is zero.");
+
+  ua.deallocate(p, 0);
+}
 
 int main() {
   queue q;
   auto dev = q.get_device();
-  auto ctxt = q.get_context();
 
   if (dev.get_info<info::device::usm_host_allocations>()) {
-    sycl::usm_allocator<int, sycl::usm::alloc::host> ua{ctxt, dev};
-    int *p = ua.allocate(ALLOC_SIZE);
-
-    assert(!p && "usm_allocator should return a null pointer when allocation "
-                 "size is zero.");
-
-    ua.deallocate(p, ALLOC_SIZE);
+    test<usm::alloc::host>(q);
+  }
+  if (dev.get_info<info::device::usm_shared_allocations>()) {
+    test<usm::alloc::shared>(q);
   }
 
   return 0;

From 7f1e0d3c67cc74e9ce21c61a160c796facb2d831 Mon Sep 17 00:00:00 2001
From: "Agarwal, Udit" <udit.agarwal@intel.com>
Date: Tue, 20 Feb 2024 19:24:48 -0800
Subject: [PATCH 4/4] Address reviews

---
 sycl/test-e2e/USM/usm_allocator_zero_allocation.cpp | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/sycl/test-e2e/USM/usm_allocator_zero_allocation.cpp b/sycl/test-e2e/USM/usm_allocator_zero_allocation.cpp
index 3cda72a03f064..b8aace8933c28 100644
--- a/sycl/test-e2e/USM/usm_allocator_zero_allocation.cpp
+++ b/sycl/test-e2e/USM/usm_allocator_zero_allocation.cpp
@@ -10,8 +10,7 @@ template <usm::alloc alloc_kind> void test(queue &q) {
   int *p = ua.allocate(0);
 
   assert(!p && "Our implementation of usm_allocator is expected to return a "
-               "null pointer when allocation "
-               "size is zero.");
+               "null pointer when allocation size is zero.");
 
   ua.deallocate(p, 0);
 }
@@ -20,10 +19,10 @@ int main() {
   queue q;
   auto dev = q.get_device();
 
-  if (dev.get_info<info::device::usm_host_allocations>()) {
+  if (dev.has(aspect::usm_host_allocations)) {
     test<usm::alloc::host>(q);
   }
-  if (dev.get_info<info::device::usm_shared_allocations>()) {
+  if (dev.has(aspect::usm_shared_allocations)) {
     test<usm::alloc::shared>(q);
   }