[OpenMP] Strip NoInline from known OpenMP runtime functions

[jhuber6]

Summary

This patch strips the NoInline attribute from known OpenMP runtime functions.
This is done so that we can denote certain runtime functions as NoInline to
ensure their call sites are intact so they can be checked by OpenMPOpt. We
don't wan't this noinline attribute to remain for any functions after OpenMPOpt
has been run however.

[jdoerfert]

LG

llvm/lib/Transforms/IPO/OpenMPOpt.cpp

 
 #define OMP_RTL(_Enum, _Name, _IsVarArg, _ReturnType, ...)                     \
   {                                                                            \
     SmallVector<Type *, 8> ArgsTypes({__VA_ARGS__});                           \
     Function *F = M.getFunction(_Name);                                        \
     RTLFunctions.insert(F);                                                    \
     if (declMatchesRTFTypes(F, OMPBuilder._ReturnType, ArgsTypes)) {           \
       RuntimeFunctionIDMap[F] = _Enum;                                         \
+      F->removeFnAttr(Attribute::NoInline);                                    \
       auto &RFI = RFIs[_Enum];                                                 \
       RFI.Kind = _Enum;                                                        \
       RFI.Name = _Name;                                                        \
       RFI.IsVarArg = _IsVarArg;                                                \
       RFI.ReturnType = OMPBuilder._ReturnType;                                 \
       RFI.ArgumentTypes = std::move(ArgsTypes);                                \
       RFI.Declaration = F;                                                     \
       unsigned NumUses = collectUses(RFI);                                     \

llvm/test/Transforms/OpenMP/add_attributes.ll

 declare i8* @__kmpc_task_reduction_get_th_data(i32, i8*, i8*)
 
 declare i8* @__kmpc_task_reduction_init(i32, i32, i8*)
 
 declare i8* @__kmpc_task_reduction_modifier_init(i8*, i32, i32, i32, i8*)
 
 declare void @__kmpc_proxy_task_completed_ooo(i8*)
 
-; Function Attrs: noinline
+; Function Attrs: noinline cold
 declare void @__kmpc_barrier_simple_spmd(%struct.ident_t* nocapture nofree readonly, i32) #0
 
-attributes #0 = { noinline }
+attributes #0 = { noinline cold }
 
 ; CHECK: ; Function Attrs: nounwind
 ; CHECK-NEXT: declare dso_local void @omp_set_num_threads(i32)
 
 ; CHECK: ; Function Attrs: nounwind
 ; CHECK-NEXT: declare dso_local void @omp_set_dynamic(i32)
 
 ; CHECK: ; Function Attrs: nounwind

 ; CHECK-NEXT: declare i8* @__kmpc_task_reduction_init(i32, i32, i8*)
 
 ; CHECK: ; Function Attrs: nounwind
 ; CHECK-NEXT: declare i8* @__kmpc_task_reduction_modifier_init(i8*, i32, i32, i32, i8*)
 
 ; CHECK: ; Function Attrs: nounwind
 ; CHECK-NEXT: declare void @__kmpc_proxy_task_completed_ooo(i8*)
 
-; CHECK: ; Function Attrs: convergent noinline nounwind
+; CHECK: ; Function Attrs: cold convergent nounwind
 ; CHECK-NEXT: declare void @__kmpc_barrier_simple_spmd(%struct.ident_t* nocapture nofree readonly, i32)
 
 ; OPTIMISTIC: ; Function Attrs: inaccessiblememonly nofree nosync nounwind willreturn writeonly
 ; OPTIMISTIC-NEXT: declare dso_local void @omp_set_num_threads(i32)
 
 ; OPTIMISTIC: ; Function Attrs: inaccessiblememonly nofree nosync nounwind willreturn writeonly
 ; OPTIMISTIC-NEXT: declare dso_local void @omp_set_dynamic(i32)
 

 ; OPTIMISTIC-NEXT: declare noalias i8* @__kmpc_task_reduction_init(i32, i32, i8*)
 
 ; OPTIMISTIC: ; Function Attrs: nofree nosync nounwind willreturn
 ; OPTIMISTIC-NEXT: declare noalias i8* @__kmpc_task_reduction_modifier_init(i8*, i32, i32, i32, i8*)
 
 ; OPTIMISTIC: ; Function Attrs: nofree nosync nounwind willreturn
 ; OPTIMISTIC-NEXT: declare void @__kmpc_proxy_task_completed_ooo(i8*)
 
-; OPTIMISTIC: ; Function Attrs: convergent noinline nounwind 
+; OPTIMISTIC: ; Function Attrs: cold convergent nounwind 
 ; OPTIMISTIC-NEXT: declare void @__kmpc_barrier_simple_spmd(%struct.ident_t* nocapture nofree readonly, i32)
 
 !llvm.module.flags = !{!0}
 
 !0 = !{i32 7, !"openmp", i32 50}