Revert "Properly convert all declaration non-type template arguments when"

This reverts commit 11d10527852b4d3ed738aa90d8bec0f398160593.

This change is problematic with function pointer template parameters. For
example, building libcxxabi with futexes (-D_LIBCXXABI_USE_FUTEX) produces this
diagnostic:

    In file included from .../llvm-project/libcxxabi/src/cxa_guard.cpp:15:
    .../llvm-project/libcxxabi/src/cxa_guard_impl.h:416:54: error: address of function 'PlatformThreadID' will always evaluate to 'true' [-Werror,-Wpointer-bool-conversion]
        has_thread_id_support(this->thread_id_address && GetThreadIDArg),
                                                      ~~ ^~~~~~~~~~~~~~
    .../llvm-project/libcxxabi/src/cxa_guard.cpp:38:26: note: in instantiation of member function '__cxxabiv1::(anonymous namespace)::InitByteFutex<&__cxxabiv1::(anonymous namespace)::PlatformFutexWait, &__cxxabiv1::(anonymous namespace)::PlatformFutexWake, &__cxxabiv1::(anonymous namespace)::PlatformThreadID>::InitByteFutex' requested here
      SelectedImplementation imp(raw_guard_object);
                             ^
    .../llvm-project/libcxxabi/src/cxa_guard_impl.h:416:54: note: prefix with the address-of operator to silence this warning
        has_thread_id_support(this->thread_id_address && GetThreadIDArg),
                                                         ^
                                                         &
    1 error generated.

The diagnostic is incorrect: adding the address-of operator also fails ("cannot
take the address of an rvalue of type 'uint32_t (*)()' (aka 'unsigned int
(*)()')").

2 files changed, 4 insertions, 35 deletions

diff --git a/clang/test/SemaCXX/exceptions-seh.cpp b/clang/test/SemaCXX/exceptions-seh.cpp
index 02bb786160d..1d8cc4917e9 100644
--- a/clang/test/SemaCXX/exceptions-seh.cpp
+++ b/clang/test/SemaCXX/exceptions-seh.cpp
@@ -39,13 +39,14 @@ void instantiate_bad_scope_tmpl() {
 }
 
 #if __cplusplus < 201103L
+// FIXME: Diagnose this case. For now we produce undef in codegen.
 template <typename T, T FN()>
 T func_template() {
-  return FN(); // expected-error 2{{builtin functions must be directly called}}
+  return FN();
 }
 void inject_builtins() {
-  func_template<void *, __exception_info>(); // expected-note {{instantiation of}}
-  func_template<unsigned long, __exception_code>(); // expected-note {{instantiation of}}
+  func_template<void *, __exception_info>();
+  func_template<unsigned long, __exception_code>();
 }
 #endif
 
diff --git a/clang/test/SemaTemplate/temp_arg_nontype_cxx1z.cpp b/clang/test/SemaTemplate/temp_arg_nontype_cxx1z.cpp
index 7232598215a..7a58dd5dcae 100644
--- a/clang/test/SemaTemplate/temp_arg_nontype_cxx1z.cpp
+++ b/clang/test/SemaTemplate/temp_arg_nontype_cxx1z.cpp
@@ -394,21 +394,6 @@ namespace PR42362 {
   Z<f, f, f>::Q q;
 }
 
-namespace QualConv {
-  int *X;
-  template<const int *const *P> void f() {
-    using T = decltype(P);
-    using T = const int* const*;
-  }
-  template void f<&X>();
-
-  template<const int *const &R> void g() {
-    using T = decltype(R);
-    using T = const int *const &;
-  }
-  template void g<(const int *const&)X>();
-}
-
 namespace FunctionConversion {
   struct a { void c(char *) noexcept; };
   template<void (a::*f)(char*)> void g() {
@@ -416,21 +401,4 @@ namespace FunctionConversion {
     using T = void (a::*)(char*); // (not 'noexcept')
   }
   template void g<&a::c>();
-
-  void c() noexcept;
-  template<void (*p)()> void h() {
-    using T = decltype(p);
-    using T = void (*)(); // (not 'noexcept')
-  }
-  template void h<&c>();
-}
-
-namespace VoidPtr {
-  // Note, this is an extension in C++17 but valid in C++20.
-  template<void *P> void f() {
-    using T = decltype(P);
-    using T = void*;
-  }
-  int n;
-  template void f<(void*)&n>();
 }