[PATCH] D105647: [OPENMP]Do no privatize const firstprivates in target regions.

[Alexey Bataev via Phabricator via cfe-commits]

ABataev created this revision.
ABataev added reviewers: jdoerfert, jhuber6.
Herald added subscribers: guansong, yaxunl.
ABataev requested review of this revision.
Herald added a subscriber: sstefan1.
Herald added a project: clang.

No need to emit private copyfor firstprivate constants in target
regions, we can use the original copy instead.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D105647

Files:
  clang/lib/CodeGen/CGStmtOpenMP.cpp
  clang/test/OpenMP/nvptx_target_firstprivate_codegen.cpp
  clang/test/OpenMP/target_firstprivate_codegen.cpp


Index: clang/test/OpenMP/target_firstprivate_codegen.cpp
===================================================================
--- clang/test/OpenMP/target_firstprivate_codegen.cpp
+++ clang/test/OpenMP/target_firstprivate_codegen.cpp
@@ -366,7 +366,7 @@
 
   // TCHECK:  define weak void @__omp_offloading_{{.+}}(double* [[PTR_IN:%.+]], [[TTII]]* nonnull align {{[0-9]+}} dereferenceable({{[0-9]+}}) [[E:%.+]])
   // TCHECK:  [[PTR_ADDR:%.+]] = alloca double*,
-  // TCHECK: alloca [[TTII]],
+  // TCHECK-NOT: alloca [[TTII]],
   // TCHECK-NOT: alloca double*,
   // TCHECK:  store double* [[PTR_IN]], double** [[PTR_ADDR]],
   // TCHECK-NOT: store double* %
Index: clang/test/OpenMP/nvptx_target_firstprivate_codegen.cpp
===================================================================
--- clang/test/OpenMP/nvptx_target_firstprivate_codegen.cpp
+++ clang/test/OpenMP/nvptx_target_firstprivate_codegen.cpp
@@ -35,7 +35,7 @@
 
   // TCHECK:  define {{.*}}void @__omp_offloading_{{.+}}([10 x float] addrspace(1)* noalias [[B_IN:%.+]], i{{[0-9]+}} [[A_IN:%.+]], [[TTII]]* noalias [[E_IN:%.+]])
   // TCHECK:  [[A_ADDR:%.+]] = alloca i{{[0-9]+}},
-  // TCHECK: alloca [[TTII]],
+  // TCHECK-NOT: alloca [[TTII]],
   // TCHECK: alloca i{{[0-9]+}},
   // TCHECK:  store i{{[0-9]+}} [[A_IN]], i{{[0-9]+}}* [[A_ADDR]],
   // TCHECK:  ret void
Index: clang/lib/CodeGen/CGStmtOpenMP.cpp
===================================================================
--- clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -786,6 +786,9 @@
                                                 OMPPrivateScope &PrivateScope) {
   if (!HaveInsertPoint())
     return false;
+  bool DeviceConstTarget =
+      getLangOpts().OpenMPIsDevice &&
+      isOpenMPTargetExecutionDirective(D.getDirectiveKind());
   bool FirstprivateIsLastprivate = false;
   llvm::DenseMap<const VarDecl *, OpenMPLastprivateModifier> Lastprivates;
   for (const auto *C : D.getClausesOfKind<OMPLastprivateClause>()) {
@@ -818,6 +821,16 @@
         ++InitsRef;
         continue;
       }
+      // Do not emit copy for firstprivate constant variables in target regions,
+      // captured by reference.
+      if (DeviceConstTarget && OrigVD->getType().isConstant(getContext()) &&
+          FD && FD->getType()->isReferenceType() &&
+          (!VD || !VD->hasAttr<OMPAllocateDeclAttr>())) {
+        EmittedAsFirstprivate.insert(OrigVD->getCanonicalDecl());
+        ++IRef;
+        ++InitsRef;
+        continue;
+      }
       FirstprivateIsLastprivate =
           FirstprivateIsLastprivate || ThisFirstprivateIsLastprivate;
       if (EmittedAsFirstprivate.insert(OrigVD->getCanonicalDecl()).second) {


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