[llvm] [OpenMP][Offload] Restore __kmpc_* function signatures (PR #156104)

[Robert Imschweiler via llvm-commits]

https://github.com/ro-i created https://github.com/llvm/llvm-project/pull/156104

Avoid altering existing function signatures of the kmpc interface to fix regressions in the runtime.

>From 65710a0ad7003c87b8d90840d0005b80a481a249 Mon Sep 17 00:00:00 2001
From: Robert Imschweiler <robert.imschweiler at amd.com>
Date: Fri, 29 Aug 2025 15:49:18 -0500
Subject: [PATCH] [OpenMP][Offload] Restore __kmpc_* function signatures

Avoid altering existing function signatures of the kmpc interface to fix
regressions in the runtime.
---
 offload/DeviceRTL/src/Parallelism.cpp | 47 ++++++++++++++++++++-------
 1 file changed, 36 insertions(+), 11 deletions(-)

diff --git a/offload/DeviceRTL/src/Parallelism.cpp b/offload/DeviceRTL/src/Parallelism.cpp
index aa5e74029ec3e..0ea2f89337fee 100644
--- a/offload/DeviceRTL/src/Parallelism.cpp
+++ b/offload/DeviceRTL/src/Parallelism.cpp
@@ -103,11 +103,10 @@ 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, int32_t nt_strict = false,
-                     int32_t nt_severity = severity_fatal,
-                     const char *nt_message = nullptr) {
+[[clang::always_inline]] void __kmpc_parallel_spmd_impl(
+    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, nt_strict, nt_severity, nt_message);
@@ -163,7 +162,22 @@ __kmpc_parallel_spmd(IdentTy *ident, int32_t num_threads, void *fn, void **args,
   return;
 }
 
-[[clang::always_inline]] void __kmpc_parallel_51(
+[[clang::always_inline]] void __kmpc_parallel_spmd(IdentTy *ident,
+                                                   int32_t num_threads,
+                                                   void *fn, void **args,
+                                                   const int64_t nargs) {
+  return __kmpc_parallel_spmd_impl(ident, num_threads, fn, args, nargs);
+}
+
+[[clang::always_inline]] void __kmpc_parallel_spmd_60(
+    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) {
+  return __kmpc_parallel_spmd_impl(ident, num_threads, fn, args, nargs,
+                                   nt_strict, nt_severity, nt_message);
+}
+
+[[clang::always_inline]] void __kmpc_parallel_impl(
     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,
@@ -198,8 +212,11 @@ __kmpc_parallel_spmd(IdentTy *ident, int32_t num_threads, void *fn, void **args,
     // 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, nt_strict,
-                         nt_severity, nt_message);
+    if (nt_strict)
+      __kmpc_parallel_spmd(ident, num_threads, fn, args, nargs);
+    else
+      __kmpc_parallel_spmd_60(ident, num_threads, fn, args, nargs, nt_strict,
+                              nt_severity, nt_message);
 
     return;
   }
@@ -308,14 +325,22 @@ __kmpc_parallel_spmd(IdentTy *ident, int32_t num_threads, void *fn, void **args,
     __kmpc_end_sharing_variables();
 }
 
+[[clang::always_inline]] void
+__kmpc_parallel_51(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) {
+  return __kmpc_parallel_impl(ident, id, if_expr, num_threads, proc_bind, fn,
+                              wrapper_fn, args, nargs);
+}
+
 [[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);
+  return __kmpc_parallel_impl(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) {