[llvm-branch-commits] [OpenMP] Widen taskgraph graph_id to uintptr_t (PR #200403)

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<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-codegen

Author: Julian Brown (jtb20)

<details>
<summary>Changes</summary>

The 'graph_id' clause introduced in OpenMP 6.0 lets the user attach an
identifying value to a taskgraph instance, and a potentially-useful
idiom is to pass a pointer expression so that each instance can uniquely
depend on the pointed-to data.  The corresponding runtime entry point
__kmpc_taskgraph and the kmp_taskgraph_record_t::graph_id field were
declared as 32-bit types, which silently truncates such pointer values
on LP64 targets.

Widen the field and the runtime ABI to uintptr_t, lower 'graph_id'
to CGM.IntPtrTy in emitTaskgraphCall, and mark the OMPRTL
descriptor as SizeTy so the call is typed consistently on 32- and
64-bit hosts.  Refresh the auto-generated CHECK line in
taskgraph_codegen.cpp accordingly.

Assisted-By: Claude Opus 4.7


---
Full diff: https://github.com/llvm/llvm-project/pull/200403.diff


5 Files Affected:

- (modified) clang/lib/CodeGen/CGOpenMPRuntime.cpp (+2-2) 
- (modified) clang/test/OpenMP/taskgraph_codegen.cpp (+1-1) 
- (modified) llvm/include/llvm/Frontend/OpenMP/OMPKinds.def (+1-1) 
- (modified) openmp/runtime/src/kmp.h (+2-2) 
- (modified) openmp/runtime/src/kmp_tasking.cpp (+1-1) 


``````````diff
diff --git a/clang/lib/CodeGen/CGOpenMPRuntime.cpp b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
index e770241cf4cab..9f00545cd0839 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntime.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntime.cpp
@@ -2269,13 +2269,13 @@ void CGOpenMPRuntime::emitTaskgraphCall(CodeGenFunction &CGF,
     GraphReset = CGF.Builder.getInt32(0);
   }
 
-  llvm::Value *GraphId = CGF.Builder.getInt32(0);
+  llvm::Value *GraphId = llvm::ConstantInt::get(CGM.IntPtrTy, 0);
   const OMPGraphIdClause *GraphIdClause = D.getSingleClause<OMPGraphIdClause>();
   if (GraphIdClause) {
     const auto *E = GraphIdClause->getId();
     auto *GraphIdVal = CGF.EmitScalarExpr(E);
     GraphId =
-        CGF.Builder.CreateIntCast(GraphIdVal, CGM.Int32Ty, /*isSigned=*/false);
+        CGF.Builder.CreateIntCast(GraphIdVal, CGM.IntPtrTy, /*isSigned=*/false);
   }
 
   CodeGenFunction OutlinedCGF(CGM, /*suppressNewContext=*/true);
diff --git a/clang/test/OpenMP/taskgraph_codegen.cpp b/clang/test/OpenMP/taskgraph_codegen.cpp
index 3f661e6bfe3d5..e6e718c2cd6d5 100644
--- a/clang/test/OpenMP/taskgraph_codegen.cpp
+++ b/clang/test/OpenMP/taskgraph_codegen.cpp
@@ -22,7 +22,7 @@
 // CHECK-NEXT:    store ptr [[X]], ptr [[TMP1]], align 8
 // CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds nuw [[STRUCT_ANON]], ptr [[AGG_CAPTURED]], i32 0, i32 1
 // CHECK-NEXT:    store ptr [[Y]], ptr [[TMP2]], align 8
-// CHECK-NEXT:    call void @__kmpc_taskgraph(ptr @[[GLOB1]], i32 [[TMP0]], ptr @.omp.taskgraph.handle, i32 0, i32 0, i32 0, ptr @taskgraph.omp_outlined., ptr [[AGG_CAPTURED]])
+// CHECK-NEXT:    call void @__kmpc_taskgraph(ptr @[[GLOB1]], i32 [[TMP0]], ptr @.omp.taskgraph.handle, i64 0, i32 0, i32 0, ptr @taskgraph.omp_outlined., ptr [[AGG_CAPTURED]])
 // CHECK-NEXT:    ret i32 0
 //
 int main() {
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMPKinds.def b/llvm/include/llvm/Frontend/OpenMP/OMPKinds.def
index 49aeecd426a32..fc24280eaa077 100644
--- a/llvm/include/llvm/Frontend/OpenMP/OMPKinds.def
+++ b/llvm/include/llvm/Frontend/OpenMP/OMPKinds.def
@@ -357,7 +357,7 @@ __OMP_RTL(__kmpc_omp_task, false, Int32, IdentPtr, Int32,
           /* kmp_task_t */ VoidPtr)
 __OMP_RTL(__kmpc_end_taskgroup, false, Void, IdentPtr, Int32)
 __OMP_RTL(__kmpc_taskgroup, false, Void, IdentPtr, Int32)
-__OMP_RTL(__kmpc_taskgraph, false, Void, IdentPtr, Int32, VoidPtrPtr, Int32,
+__OMP_RTL(__kmpc_taskgraph, false, Void, IdentPtr, Int32, VoidPtrPtr, SizeTy,
           Int32, Int32, VoidPtr, VoidPtr)
 __OMP_RTL(__kmpc_taskgraph_task, false, Int32, IdentPtr, Int32, VoidPtr, Int32,
           SizeTy, VoidPtr, SizeTy, Int32, VoidPtr)
diff --git a/openmp/runtime/src/kmp.h b/openmp/runtime/src/kmp.h
index 55267161d4b8a..d660c4e191d13 100644
--- a/openmp/runtime/src/kmp.h
+++ b/openmp/runtime/src/kmp.h
@@ -2760,7 +2760,7 @@ typedef struct kmp_taskgraph_region {
 typedef struct kmp_taskgraph_record {
   std::atomic<kmp_taskgraph_status_t> status = KMP_TDG_NONE;
   kmp_int32 gtid = 0;
-  kmp_int32 graph_id = 0;
+  uintptr_t graph_id = 0;
   // A lock that protects the record_map and num_tasks fields from being
   // modified by multiple threads.
   // For now, we also use this whilst the taskgraph is being replayed.
@@ -4502,7 +4502,7 @@ KMP_EXPORT void __kmpc_init_nest_lock_with_hint(ident_t *loc, kmp_int32 gtid,
 #if OMP_TASKGRAPH_EXPERIMENTAL
 KMP_EXPORT void __kmpc_taskgraph(ident_t *loc_ref, kmp_int32 gtid,
                                  std::atomic<void *> *tdg_handle,
-                                 kmp_uint32 graph_id, kmp_int32 graph_reset,
+                                 uintptr_t graph_id, kmp_int32 graph_reset,
                                  kmp_int32 nogroup, void (*entry)(void *),
                                  void *args);
 KMP_EXPORT kmp_uint32 __kmpc_taskgraph_task(
diff --git a/openmp/runtime/src/kmp_tasking.cpp b/openmp/runtime/src/kmp_tasking.cpp
index a6ed83fc4748e..2f73a75f11e7c 100644
--- a/openmp/runtime/src/kmp_tasking.cpp
+++ b/openmp/runtime/src/kmp_tasking.cpp
@@ -5906,7 +5906,7 @@ __kmp_expire_taskgraph_records(kmp_int32 gtid,
 // entry:       Pointer to the entry function
 // args:        Pointer to the function arguments
 void __kmpc_taskgraph(ident_t *loc_ref, kmp_int32 gtid,
-                      std::atomic<void *> *tdg_handle, kmp_uint32 graph_id,
+                      std::atomic<void *> *tdg_handle, uintptr_t graph_id,
                       kmp_int32 graph_reset, kmp_int32 nogroup,
                       void (*entry)(void *), void *args) {
   kmp_taskgraph_header_t *header =

``````````

</details>


https://github.com/llvm/llvm-project/pull/200403