c++: avoid ICE with __builtin_memset (PR90997).

warn_for_memset calls fold_for_warn, which calls fold_non_dependent_expr, so
also calling instantiate_non_dependent_expr here is undesirable.

	PR c++/90997
	* semantics.c (finish_call_expr): Don't call
	instantiate_non_dependent_expr before warn_for_memset.

gcc/cp/ChangeLog

+2020-01-26  Jason Merrill  <jason@redhat.com>
+
+	PR c++/90997
+	* semantics.c (finish_call_expr): Don't call
+	instantiate_non_dependent_expr before warn_for_memset.
+
 2020-01-25  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/93414 - poor diagnostic for dynamic_cast in constexpr context.

gcc/cp/semantics.c

@@ -2664,7 +2664,6 @@ finish_call_expr (tree fn, vec<tree, va_gc> **args, bool disallow_virtual,
 	      tree arg2 = (*orig_args)[2];
 	      int literal_mask = ((literal_integer_zerop (arg1) << 1)
 				  | (literal_integer_zerop (arg2) << 2));
-	      arg2 = instantiate_non_dependent_expr (arg2);
 	      warn_for_memset (input_location, arg0, arg2, literal_mask);
 	    }
 

gcc/testsuite/g++.dg/ext/builtin14.C

+// PR c++/90997
+
+template<class> void f ()
+{ __builtin_memset (0, 0, int(0.)); }