* pt.c (convert_nontype_argument): Issue an error when presented

	with an integer (real) constant that cannot be simplified to an
	INT_CST (REAL_CST).


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@20550 138bc75d-0d04-0410-961f-82ee72b054a4

3 files changed, 31 insertions, 2 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 284c9c082c5..5af8932281e 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 1998-06-17  Mark Mitchell  <mark@markmitchell.com>
 
+	* pt.c (convert_nontype_argument): Issue an error when presented
+	with an integer (real) constant that cannot be simplified to an
+	INT_CST (REAL_CST).
+
 	* cp-tree.h (c_get_alias_set): Remove declaration added in
 	1998-06-13 change that should never have been checked in.
 
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 9fe7fdd6ccb..3b883b8c06b 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -2056,6 +2056,7 @@ convert_nontype_argument (type, expr)
     {
       if (! TREE_CONSTANT (expr))
 	{
+	non_constant:
 	  cp_error ("non-constant `%E' cannot be used as template argument",
 		    expr);
 	  return NULL_TREE;
@@ -2128,15 +2129,28 @@ convert_nontype_argument (type, expr)
       
       /* It's safe to call digest_init in this case; we know we're
 	 just converting one integral constant expression to another.  */
-      return digest_init (type, expr, (tree*) 0);
+      expr = digest_init (type, expr, (tree*) 0);
 
+      if (TREE_CODE (expr) != INTEGER_CST)
+	/* Curiously, some TREE_CONSTNAT integral expressions do not
+	   simplify to integer constants.  For example, `3 % 0',
+	   remains a TRUNC_MOD_EXPR.  */
+	goto non_constant;
+      
+      return expr;
+	
     case REAL_TYPE:
     case COMPLEX_TYPE:
       /* These are g++ extensions.  */
       if (TREE_CODE (expr_type) != TREE_CODE (type))
 	return error_mark_node;
 
-      return digest_init (type, expr, (tree*) 0);
+      expr = digest_init (type, expr, (tree*) 0);
+      
+      if (TREE_CODE (expr) != REAL_CST)
+	goto non_constant;
+
+      return expr;
 
     case POINTER_TYPE:
       {
diff --git a/gcc/testsuite/g++.old-deja/g++.pt/crash10.C b/gcc/testsuite/g++.old-deja/g++.pt/crash10.C
new file mode 100644
index 00000000000..974cafc8731
--- /dev/null
+++ b/gcc/testsuite/g++.old-deja/g++.pt/crash10.C
@@ -0,0 +1,11 @@
+// Build don't link:
+
+template<int M, int N>
+class GCD {
+public:
+  enum { val = (N == 0) ? M : GCD<N, M % N>::val }; 
+};
+
+main() {
+  GCD< 1, 0 >::val; // ERROR - division
+}