[llvm] [libsycl] USM Aligned allocation functions (PR #213468)

[via llvm-commits]

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@@ -33,18 +47,40 @@ void *malloc_device(std::size_t numBytes, const queue &syclQueue,
 
 // SYCL 2020 4.8.3.3. Host allocation functions.
 
-void *malloc_host(std::size_t numBytes, const context &syclContext,
-                  const property_list &propList) {
+static device getHostAllocDevice(const context &syclContext) {
   auto ContextDevices = syclContext.get_devices();
-  assert(!ContextDevices.empty() && "Context can't be created without device");
-  if (std::none_of(
-          ContextDevices.begin(), ContextDevices.end(),
-          [](device Dev) { return Dev.has(aspect::usm_host_allocations); }))
+
+  auto It = std::find_if(
+      ContextDevices.begin(), ContextDevices.end(),
+      [](const device &Dev) { return Dev.has(aspect::usm_host_allocations); });
+
+  if (It == ContextDevices.end()) {
     throw sycl::exception(
         sycl::errc::feature_not_supported,
-        "All devices of context do not support host USM allocations.");
-  return malloc(numBytes, ContextDevices[0], syclContext, usm::alloc::host,
-                propList);
+        "None of the context's devices support host USM allocations.");
+  }
+  return *It;
+}
+
+void *aligned_alloc_host(size_t alignment, size_t numBytes,
+                         const context &syclContext,
+                         const property_list &propList) {
+  auto device = getHostAllocDevice(syclContext);
+  return aligned_alloc(alignment, numBytes, device, syclContext,
+                       usm::alloc::host, propList);
+}
+
+void *aligned_alloc_host(size_t alignment, size_t numBytes,
+                         const queue &syclQueue,
+                         const property_list &propList) {
+  return aligned_alloc_host(alignment, numBytes, syclQueue.get_context(),
+                            propList);
+}
+
+void *malloc_host(std::size_t numBytes, const context &syclContext,
+                  const property_list &propList) {
+  return aligned_alloc_host(alignof(std::max_align_t), numBytes, syclContext,
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Robertkq wrote:

alignment guarantee from [sycl specs](https://registry.khronos.org/SYCL/specs/sycl-2020/html/sycl-2020.html#_usm_allocations). See row 1 of Table n. 70

https://github.com/llvm/llvm-project/pull/213468