1 files changed, 31 insertions, 4 deletions
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index c60a17abc6f..168bf6f451d 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -240,15 +240,42 @@ static void instantiateOMPDeclareSimdDeclAttr(
     Sema &S, const MultiLevelTemplateArgumentList &TemplateArgs,
     const OMPDeclareSimdDeclAttr &Attr, Decl *New) {
   ExprResult Simdlen;
-  if (auto *E = Attr.getSimdlen()) {
+  if (auto *E = Attr.getSimdlen())
     Simdlen = S.SubstExpr(E, TemplateArgs);
-    if (Simdlen.isInvalid())
-      return;
+  // Allow 'this' in clauses with varlists.
+  if (auto *FTD = dyn_cast<FunctionTemplateDecl>(New))
+    New = FTD->getTemplatedDecl();
+  auto *FD = cast<FunctionDecl>(New);
+  auto *ThisContext = dyn_cast_or_null<CXXRecordDecl>(FD->getDeclContext());
+  SmallVector<Expr *, 4> Uniforms;
+
+  auto &&Subst = [&](Expr *E) -> ExprResult {
+    if (auto *DRE = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
+      if (auto *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl())) {
+        Sema::ContextRAII SavedContext(S, FD);
+        LocalInstantiationScope Local(S);
+        if (FD->getNumParams() > PVD->getFunctionScopeIndex())
+          Local.InstantiatedLocal(
+              PVD, FD->getParamDecl(PVD->getFunctionScopeIndex()));
+        return S.SubstExpr(E, TemplateArgs);
+      }
+    Sema::CXXThisScopeRAII ThisScope(S, ThisContext, /*TypeQuals=*/0,
+                                     FD->isCXXInstanceMember());
+    return S.SubstExpr(E, TemplateArgs);
+  };
+
+  if (Attr.uniforms_size() > 0) {
+    for(auto *E : Attr.uniforms()) {
+      ExprResult Inst = Subst(E);
+      if (Inst.isInvalid())
+        continue;
+      Uniforms.push_back(Inst.get());
+    }
   }
 
   (void)S.ActOnOpenMPDeclareSimdDirective(S.ConvertDeclToDeclGroup(New),
                                           Attr.getBranchState(), Simdlen.get(),
-                                          Attr.getRange());
+                                          Uniforms, Attr.getRange());
 }
 
 void Sema::InstantiateAttrs(const MultiLevelTemplateArgumentList &TemplateArgs,