diff --git a/offload/DeviceRTL/include/DeviceTypes.h b/offload/DeviceRTL/include/DeviceTypes.hindex 2e5d92380f040..111143a5578f1 100644--- a/offload/DeviceRTL/include/DeviceTypes.h+++ b/offload/DeviceRTL/include/DeviceTypes.h@@ -136,6 +136,12 @@ struct omp_lock_t {   void *Lock; };+// see definition in openmp/runtime kmp.h+typedef enum omp_severity_t {+  severity_warning = 1,+  severity_fatal = 2+} omp_severity_t;+ using InterWarpCopyFnTy = void (*)(void *src, int32_t warp_num); using ShuffleReductFnTy = void (*)(void *rhsData, int16_t lane_id,                                    int16_t lane_offset, int16_t shortCircuit);diff --git a/offload/DeviceRTL/src/Parallelism.cpp b/offload/DeviceRTL/src/Parallelism.cppindex 08ce616aee1c4..78438a60454b8 100644--- a/offload/DeviceRTL/src/Parallelism.cpp+++ b/offload/DeviceRTL/src/Parallelism.cpp@@ -45,7 +45,24 @@ using namespace ompx;  namespace {-uint32_t determineNumberOfThreads(int32_t NumThreadsClause) {+void num_threads_strict_error(int32_t nt_strict, int32_t nt_severity,+                              const char *nt_message, int32_t requested,+                              int32_t actual) {+  if (nt_message)+    printf("%s\n", nt_message);+  else+    printf("The computed number of threads (%u) does not match the requested "+           "number of threads (%d). Consider that it might not be supported "+           "to select exactly %d threads on this target device.\n",+           actual, requested, requested);+  if (nt_severity == severity_fatal)+    __builtin_trap();+}++uint32_t determineNumberOfThreads(int32_t NumThreadsClause,+                                  int32_t nt_strict = false,+                                  int32_t nt_severity = severity_fatal,+                                  const char *nt_message = nullptr) {   uint32_t NThreadsICV =       NumThreadsClause != -1 ? NumThreadsClause : icv::NThreads;   uint32_t NumThreads = mapping::getMaxTeamThreads();@@ -55,13 +72,17 @@ uint32_t determineNumberOfThreads(int32_t NumThreadsClause) {    // SPMD mode allows any number of threads, for generic mode we round down to a   // multiple of WARPSIZE since it is legal to do so in OpenMP.-  if (mapping::isSPMDMode())-    return NumThreads;+  if (!mapping::isSPMDMode()) {+    if (NumThreads < mapping::getWarpSize())+      NumThreads = 1;+    else+      NumThreads = (NumThreads & ~((uint32_t)mapping::getWarpSize() - 1));+  }-  if (NumThreads < mapping::getWarpSize())-    NumThreads = 1;-  else-    NumThreads = (NumThreads & ~((uint32_t)mapping::getWarpSize() - 1));+  if (NumThreadsClause != -1 && nt_strict &&+      NumThreads != static_cast<uint32_t>(NumThreadsClause))+    num_threads_strict_error(nt_strict, nt_severity, nt_message,+                             NumThreadsClause, NumThreads);    return NumThreads; }@@ -82,12 +103,14 @@ uint32_t determineNumberOfThreads(int32_t NumThreadsClause) {  extern "C" {-[[clang::always_inline]] void __kmpc_parallel_spmd(IdentTy *ident,-                                                   int32_t num_threads,-                                                   void *fn, void **args,-                                                   const int64_t nargs) {+[[clang::always_inline]] void+__kmpc_parallel_spmd(IdentTy *ident, int32_t num_threads, void *fn, void **args,+                     const int64_t nargs, int32_t nt_strict = false,+                     int32_t nt_severity = severity_fatal,+                     const char *nt_message = nullptr) {   uint32_t TId = mapping::getThreadIdInBlock();-  uint32_t NumThreads = determineNumberOfThreads(num_threads);+  uint32_t NumThreads =+      determineNumberOfThreads(num_threads, nt_strict, nt_severity, nt_message);   uint32_t PTeamSize =       NumThreads == mapping::getMaxTeamThreads() ? 0 : NumThreads;   // Avoid the race between the read of the `icv::Level` above and the write@@ -140,10 +163,11 @@ extern "C" {   return; }-[[clang::always_inline]] void-__kmpc_parallel_51(IdentTy *ident, int32_t, int32_t if_expr,-                   int32_t num_threads, int proc_bind, void *fn,-                   void *wrapper_fn, void **args, int64_t nargs) {+[[clang::always_inline]] void __kmpc_parallel_51(+    IdentTy *ident, int32_t, int32_t if_expr, int32_t num_threads,+    int proc_bind, void *fn, void *wrapper_fn, void **args, int64_t nargs,+    int32_t nt_strict = false, int32_t nt_severity = severity_fatal,+    const char *nt_message = nullptr) {   uint32_t TId = mapping::getThreadIdInBlock();    // Assert the parallelism level is zero if disabled by the user.@@ -156,6 +180,12 @@ __kmpc_parallel_51(IdentTy *ident, int32_t, int32_t if_expr,   // 3) nested parallel regions   if (OMP_UNLIKELY(!if_expr || state::HasThreadState ||                    (config::mayUseNestedParallelism() && icv::Level))) {+    // OpenMP 6.0 12.1.2 requires the num_threads 'strict' modifier to also have+    // effect when parallel execution is disabled by a corresponding if clause+    // attached to the parallel directive.+    if (nt_strict && num_threads > 1)+      num_threads_strict_error(nt_strict, nt_severity, nt_message, num_threads,+                               1);     state::DateEnvironmentRAII DERAII(ident);     ++icv::Level;     invokeMicrotask(TId, 0, fn, args, nargs);@@ -169,12 +199,14 @@ __kmpc_parallel_51(IdentTy *ident, int32_t, int32_t if_expr,     // This was moved to its own routine so it could be called directly     // in certain situations to avoid resource consumption of unused     // logic in parallel_51.-    __kmpc_parallel_spmd(ident, num_threads, fn, args, nargs);+    __kmpc_parallel_spmd(ident, num_threads, fn, args, nargs, nt_strict,+                         nt_severity, nt_message);      return;   }-  uint32_t NumThreads = determineNumberOfThreads(num_threads);+  uint32_t NumThreads =+      determineNumberOfThreads(num_threads, nt_strict, nt_severity, nt_message);   uint32_t MaxTeamThreads = mapping::getMaxTeamThreads();   uint32_t PTeamSize = NumThreads == MaxTeamThreads ? 0 : NumThreads;@@ -277,6 +309,16 @@ __kmpc_parallel_51(IdentTy *ident, int32_t, int32_t if_expr,     __kmpc_end_sharing_variables(); }+[[clang::always_inline]] void __kmpc_parallel_60(+    IdentTy *ident, int32_t id, int32_t if_expr, int32_t num_threads,+    int proc_bind, void *fn, void *wrapper_fn, void **args, int64_t nargs,+    int32_t nt_strict = false, int32_t nt_severity = severity_fatal,+    const char *nt_message = nullptr) {+  return __kmpc_parallel_51(ident, id, if_expr, num_threads, proc_bind, fn,+                            wrapper_fn, args, nargs, nt_strict, nt_severity,+                            nt_message);+}+ [[clang::noinline]] bool __kmpc_kernel_parallel(ParallelRegionFnTy *WorkFn) {   // Work function and arguments for L1 parallel region.   *WorkFn = state::ParallelRegionFn;diff --git a/openmp/runtime/src/kmp.h b/openmp/runtime/src/kmp.hindex a2cacc8792b15..983e1c34f76b8 100644--- a/openmp/runtime/src/kmp.h+++ b/openmp/runtime/src/kmp.h@@ -4666,6 +4666,7 @@ static inline int __kmp_adjust_gtid_for_hidden_helpers(int gtid) { }  // Support for error directive+// See definition in offload/DeviceRTL DeviceTypes.h typedef enum kmp_severity_t {   severity_warning = 1,   severity_fatal = 2