re PR c++/85112 (ICE with invalid constexpr)

2018-04-16  Paolo Carlini  <paolo.carlini@oracle.com>
	    Jason Merrill  <jason@redhat.com>

	PR c++/85112
	* convert.c (convert_to_integer_1): Use direct recursion for
	enumeral types and types with a precision less than the number
	of bits in their mode.

/testsuite
2018-04-16  Paolo Carlini  <paolo.carlini@oracle.com>
	    Jason Merrill  <jason@redhat.com>

	PR c++/85112
	* g++.dg/cpp0x/pr85112.C: New.

Co-Authored-By: Jason Merrill <jason@redhat.com>

From-SVN: r259397

gcc/ChangeLog

+2018-04-16  Paolo Carlini  <paolo.carlini@oracle.com>
+	    Jason Merrill  <jason@redhat.com>
+
+	PR c++/85112
+	* convert.c (convert_to_integer_1): Use direct recursion for
+	enumeral types and types with a precision less than the number
+	of bits in their mode.
+
 2018-04-16  Julia Koval  <julia.koval@intel.com>
 
 	PR target/84413

gcc/convert.c

@@ -741,8 +741,10 @@ convert_to_integer_1 (tree type, tree expr, bool dofold)
       else if (TREE_CODE (type) == ENUMERAL_TYPE
 	       || maybe_ne (outprec, GET_MODE_PRECISION (TYPE_MODE (type))))
 	{
-	  expr = convert (lang_hooks.types.type_for_mode
-			  (TYPE_MODE (type), TYPE_UNSIGNED (type)), expr);
+	  expr
+	    = convert_to_integer_1 (lang_hooks.types.type_for_mode
+				    (TYPE_MODE (type), TYPE_UNSIGNED (type)),
+				    expr, dofold);
 	  return maybe_fold_build1_loc (dofold, loc, NOP_EXPR, type, expr);
 	}
 

gcc/testsuite/ChangeLog

+2018-04-16  Paolo Carlini  <paolo.carlini@oracle.com>
+	    Jason Merrill  <jason@redhat.com>
+
+	PR c++/85112
+	* g++.dg/cpp0x/pr85112.C: New.
+
 2018-04-15  Bill Schmidt  <wschmidt@linux.ibm.com>
 
 	PR testsuite/85326

gcc/testsuite/g++.dg/cpp0x/pr85112.C

+// PR c++/85112
+// { dg-do compile { target c++11 } }
+
+struct A
+{
+  int m;
+  int n : 4;
+};
+
+int i;  // { dg-message "not const" }
+
+void foo()
+{
+  constexpr int j = i;  // { dg-error "not usable" }
+  A a;
+  a.n = j;
+}