[CUDA][HIP] Fix init var diag in temmplate (#69081)

Currently clang diagnoses the following code:
(https://godbolt.org/z/s8zK3E5P5) but nvcc
does not.

`
struct A {
   constexpr A(){}
};

struct  B {
  A a;
  int b;
};

template<typename T>
__global__ void kernel( )
{
   __shared__ B x;
}
`

Clang generates an implicit trivial ctor for struct B, which should be
allowed for initializing a shared variable.

However, the body of the ctor is defined only if the template kernel is
instantiated. Clang checks the initialization of variable in
non-instantiated templates, where it cannot find the body of the ctor,
therefore diagnoses it.

This patch skips the check for non-instantiated templates.

1 files changed, 7 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaCUDA.cpp b/clang/lib/Sema/SemaCUDA.cpp
index 7c4083e..d993499 100644
--- a/clang/lib/Sema/SemaCUDA.cpp
+++ b/clang/lib/Sema/SemaCUDA.cpp
@@ -632,6 +632,13 @@ bool HasAllowedCUDADeviceStaticInitializer(Sema &S, VarDecl *VD,
 } // namespace
 
 void Sema::checkAllowedCUDAInitializer(VarDecl *VD) {
+  // Return early if VD is inside a non-instantiated template function since
+  // the implicit constructor is not defined yet.
+  if (const FunctionDecl *FD =
+          dyn_cast_or_null<FunctionDecl>(VD->getDeclContext()))
+    if (FD->isDependentContext())
+      return;
+
   // Do not check dependent variables since the ctor/dtor/initializer are not
   // determined. Do it after instantiation.
   if (VD->isInvalidDecl() || !VD->hasInit() || !VD->hasGlobalStorage() ||