[PATCH] D75350: [OpenMP] Allow const parameters in declare simd linear clause

[Graham Hunter via Phabricator via cfe-commits]

huntergr created this revision.
huntergr added reviewers: ABataev, kkwli0.
Herald added a subscriber: guansong.
Herald added a reviewer: jdoerfert.
Herald added a project: clang.

Section 2.19.3 (List Item Privatization) of the OpenMP 5.0 standard does not apply to declarative directives, only to constructs. As such it's legal for a const-qualified function parameter to be marked as linear in a declare simd directive. I have confirmed this with the language committee.

Suggestions on a better approach are welcome -- I tried using DSAStack, but it didn't have a valid current directive when the restriction was checked.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D75350

Files:
  clang/include/clang/Sema/Sema.h
  clang/lib/Sema/SemaOpenMP.cpp
  clang/test/OpenMP/declare_simd_codegen.cpp


Index: clang/test/OpenMP/declare_simd_codegen.cpp
===================================================================
--- clang/test/OpenMP/declare_simd_codegen.cpp
+++ clang/test/OpenMP/declare_simd_codegen.cpp
@@ -114,6 +114,9 @@
 #pragma omp declare simd notinbranch
 double foo(double x) { return 0; }
 
+#pragma omp declare simd notinbranch linear(i)
+double constlinear(const int i);
+
 // CHECK-DAG: define {{.+}}@_Z5add_1Pf(
 // CHECK-DAG: define {{.+}}@_Z1hIiEvPT_S1_S1_S1_(
 // CHECK-DAG: define {{.+}}@_Z1hIfEvPT_S1_S1_S1_(
Index: clang/lib/Sema/SemaOpenMP.cpp
===================================================================
--- clang/lib/Sema/SemaOpenMP.cpp
+++ clang/lib/Sema/SemaOpenMP.cpp
@@ -5269,7 +5269,8 @@
               E->containsUnexpandedParameterPack())
             continue;
           (void)CheckOpenMPLinearDecl(CanonPVD, E->getExprLoc(), LinKind,
-                                      PVD->getOriginalType());
+                                      PVD->getOriginalType(),
+                                      /*IsDeclareSimd=*/true);
           continue;
         }
       }
@@ -5289,7 +5290,7 @@
           E->isInstantiationDependent() || E->containsUnexpandedParameterPack())
         continue;
       (void)CheckOpenMPLinearDecl(/*D=*/nullptr, E->getExprLoc(), LinKind,
-                                  E->getType());
+                                  E->getType(), /*IsDeclareSimd=*/true);
       continue;
     }
     Diag(E->getExprLoc(), diag::err_omp_param_or_this_in_clause)
@@ -14548,7 +14549,7 @@
 
 bool Sema::CheckOpenMPLinearDecl(const ValueDecl *D, SourceLocation ELoc,
                                  OpenMPLinearClauseKind LinKind,
-                                 QualType Type) {
+                                 QualType Type, bool IsDeclareSimd) {
   const auto *VD = dyn_cast_or_null<VarDecl>(D);
   // A variable must not have an incomplete type or a reference type.
   if (RequireCompleteType(ELoc, Type, diag::err_omp_linear_incomplete_type))
@@ -14564,8 +14565,10 @@
   // OpenMP 5.0 [2.19.3, List Item Privatization, Restrictions]
   // A variable that is privatized must not have a const-qualified type
   // unless it is of class type with a mutable member. This restriction does
-  // not apply to the firstprivate clause.
-  if (rejectConstNotMutableType(*this, D, Type, OMPC_linear, ELoc))
+  // not apply to the firstprivate clause, nor to the linear clause on
+  // declarative directives (like declare simd).
+  if (!IsDeclareSimd &&
+      rejectConstNotMutableType(*this, D, Type, OMPC_linear, ELoc))
     return true;
 
   // A list item must be of integral or pointer type.
Index: clang/include/clang/Sema/Sema.h
===================================================================
--- clang/include/clang/Sema/Sema.h
+++ clang/include/clang/Sema/Sema.h
@@ -10173,7 +10173,8 @@
   /// Checks that the specified declaration matches requirements for the linear
   /// decls.
   bool CheckOpenMPLinearDecl(const ValueDecl *D, SourceLocation ELoc,
-                             OpenMPLinearClauseKind LinKind, QualType Type);
+                             OpenMPLinearClauseKind LinKind, QualType Type,
+                             bool IsDeclareSimd = false);
 
   /// Called on well-formed '\#pragma omp declare simd' after parsing of
   /// the associated method/function.


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