[OPENMP5.0]Add basic support for declare variant directive.

Added basic support for declare variant directive and its match clause
with user context selector.

llvm-svn: 371892
diff --git a/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp b/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
index 09042b9..c6c595d 100644
--- a/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
+++ b/clang/lib/CodeGen/CGOpenMPRuntimeNVPTX.cpp
@@ -795,6 +795,7 @@
     case OMPD_teams_distribute_parallel_for_simd:
     case OMPD_target_update:
     case OMPD_declare_simd:
+    case OMPD_declare_variant:
     case OMPD_declare_target:
     case OMPD_end_declare_target:
     case OMPD_declare_reduction:
@@ -865,6 +866,7 @@
   case OMPD_teams_distribute_parallel_for_simd:
   case OMPD_target_update:
   case OMPD_declare_simd:
+  case OMPD_declare_variant:
   case OMPD_declare_target:
   case OMPD_end_declare_target:
   case OMPD_declare_reduction:
@@ -1028,6 +1030,7 @@
     case OMPD_teams_distribute_parallel_for_simd:
     case OMPD_target_update:
     case OMPD_declare_simd:
+    case OMPD_declare_variant:
     case OMPD_declare_target:
     case OMPD_end_declare_target:
     case OMPD_declare_reduction:
@@ -1104,6 +1107,7 @@
   case OMPD_teams_distribute_parallel_for_simd:
   case OMPD_target_update:
   case OMPD_declare_simd:
+  case OMPD_declare_variant:
   case OMPD_declare_target:
   case OMPD_end_declare_target:
   case OMPD_declare_reduction: