[OPENMP 4.0] Initial support for 'omp declare reduction' construct.

Add parsing, sema analysis and serialization/deserialization for 'declare reduction' construct.
User-defined reductions are defined as

#pragma omp declare reduction( reduction-identifier : typename-list : combiner ) [initializer ( initializer-expr )]
These custom reductions may be used in 'reduction' clauses of OpenMP constructs. The combiner specifies how partial results can be combined into a single value. The
combiner can use the special variable identifiers omp_in and omp_out that are of the type of the variables being reduced with this reduction-identifier. Each of them will
denote one of the values to be combined before executing the combiner. It is assumed that the special omp_out identifier will refer to the storage that holds the resulting
combined value after executing the combiner.
As the initializer-expr value of a user-defined reduction is not known a priori the initializer-clause can be used to specify one. Then the contents of the initializer-clause
will be used as the initializer for private copies of reduction list items where the omp_priv identifier will refer to the storage to be initialized. The special identifier
omp_orig can also appear in the initializer-clause and it will refer to the storage of the original variable to be reduced.
Differential Revision: http://reviews.llvm.org/D11182

llvm-svn: 262582

1 files changed, 3 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index f7fe506f4ae..f20b4d06287 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -5640,7 +5640,7 @@ static bool isIncompleteDeclExternC(Sema &S, const T *D) {
 
 static bool shouldConsiderLinkage(const VarDecl *VD) {
   const DeclContext *DC = VD->getDeclContext()->getRedeclContext();
-  if (DC->isFunctionOrMethod())
+  if (DC->isFunctionOrMethod() || isa<OMPDeclareReductionDecl>(DC))
     return VD->hasExternalStorage();
   if (DC->isFileContext())
     return true;
@@ -5651,7 +5651,8 @@ static bool shouldConsiderLinkage(const VarDecl *VD) {
 
 static bool shouldConsiderLinkage(const FunctionDecl *FD) {
   const DeclContext *DC = FD->getDeclContext()->getRedeclContext();
-  if (DC->isFileContext() || DC->isFunctionOrMethod())
+  if (DC->isFileContext() || DC->isFunctionOrMethod() ||
+      isa<OMPDeclareReductionDecl>(DC))
     return true;
   if (DC->isRecord())
     return false;