re PR c++/11962 (ICE in type_dependent_expression on omitted second operand to…

re PR c++/11962 (ICE in type_dependent_expression on omitted second operand to ?: in template argument expression)

	PR c++/11962
	* typeck.c (build_x_conditional_expr): Handle missing middle
	operands in templates.
	* mangle.c (write_expression): Issue errors about attempts to
	mangle a non-existant middle operator to the ?: operator.

	PR c++/11962
	* g++.dg/template/cond2.C: New test.

From-SVN: r72785

gcc/cp/ChangeLog

+2003-10-21  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/11962
+	* typeck.c (build_x_conditional_expr): Handle missing middle
+	operands in templates.
+	* mangle.c (write_expression): Issue errors about attempts to
+	mangle a non-existant middle operator to the ?: operator.
+
 2003-10-21  Robert Bowdidge   <bowdidge@apple.com>
 	* decl.c (cp_finish_decl): Remove clause intended for asm directives 
           in struct or class fields: this code is never executed.

gcc/cp/mangle.c

@@ -2041,7 +2041,21 @@ write_expression (tree expr)
 
 	default:
 	  for (i = 0; i < TREE_CODE_LENGTH (code); ++i)
-	    write_expression (TREE_OPERAND (expr, i));
+	    {
+	      tree operand = TREE_OPERAND (expr, i);
+	      /* As a GNU expression, the middle operand of a
+		 conditional may be omitted.  Since expression
+		 manglings are supposed to represent the input token
+		 stream, there's no good way to mangle such an
+		 expression without extending the C++ ABI.  */
+	      if (code == COND_EXPR && i == 1 && !operand)
+		{
+		  error ("omitted middle operand to `?:' operand "
+			 "cannot be mangled");
+		  continue;
+		}
+	      write_expression (operand);
+	    }
 	}
     }
 }

gcc/cp/typeck.c

@@ -4284,11 +4284,13 @@ build_x_conditional_expr (tree ifexp, tree op1, tree op2)
 	 IFEXP is type-dependent, even though the eventual type of the
 	 expression doesn't dependent on IFEXP.  */
       if (type_dependent_expression_p (ifexp)
-	  || type_dependent_expression_p (op1)
+	  /* As a GNU extension, the middle operand may be omitted.  */
+	  || (op1 && type_dependent_expression_p (op1))
 	  || type_dependent_expression_p (op2))
 	return build_min_nt (COND_EXPR, ifexp, op1, op2);
       ifexp = build_non_dependent_expr (ifexp);
-      op1 = build_non_dependent_expr (op1);
+      if (op1)
+	op1 = build_non_dependent_expr (op1);
       op2 = build_non_dependent_expr (op2);
     }
 

gcc/testsuite/ChangeLog

+2003-10-21  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/11962
+	* g++.dg/template/cond2.C: New test.
+
 2003-10-20  Joseph S. Myers  <jsm@polyomino.org.uk>
 
 	* gcc.dg/builtins-28.c: New test.

gcc/testsuite/g++.dg/template/cond2.C

+// PR c++/11962
+// { dg-options "" }
+
+template<int X> class c;
+
+template<int X, int Y> int test(c<X ? : Y>&);
+
+void test(c<2>*c2) {
+	test<0, 2>(*c2); // { dg-error "omitted" }
+}