[clang][OpenMP] Fix unused var warning

This was added by 453e02ca0903c9f65529d21c513925ab0fdea1e1.Use
isa instead since we don't use the result.

Fixes:
<..>SemaOpenMP.cpp:23149:13: warning: unused variable ‘TargetVarDecl’ [-Wunused-variable]
23149 |   if (auto *TargetVarDecl = dyn_cast_or_null<VarDecl>(TargetDecl))
      |             ^~~~~~~~~~~~~

Which came up when building with GCC 9.

diff --git a/clang/lib/Sema/SemaOpenMP.cpp b/clang/lib/Sema/SemaOpenMP.cpp
index 0b6f5be..e22425b 100644 (file)
--- a/clang/lib/Sema/SemaOpenMP.cpp
+++ b/clang/lib/Sema/SemaOpenMP.cpp
@@ -23146,7 +23146,7 @@ public:
 /// variables with static storage duration in declare target directive.
 void Sema::ActOnOpenMPDeclareTargetInitializer(Decl *TargetDecl) {
   GlobalDeclRefChecker Checker;
-  if (auto *TargetVarDecl = dyn_cast_or_null<VarDecl>(TargetDecl))
+  if (isa<VarDecl>(TargetDecl))
     Checker.declareTargetInitializer(TargetDecl);
 }