[C++ PATCH] Fix ICE with bitfields (PR c++/69164, take 2)

Jakub Jelinek jakub@redhat.com
Fri Jan 8 20:09:00 GMT 2016


On Fri, Jan 08, 2016 at 09:02:34AM -0500, Jason Merrill wrote:
> On 01/08/2016 07:58 AM, Jakub Jelinek wrote:
> >On Fri, Jan 08, 2016 at 01:46:47PM +0100, Bernd Schmidt wrote:
> >>On 01/07/2016 10:43 PM, Jakub Jelinek wrote:
> >>>
> >>>	PR c++/69164
> >>>	* class.c (layout_class_type): Also copy DEC_SIZE_UNIT, DECL_BIT_FIELD
> >>>	and DEC_BIT_FIELD_TYPE.
> >>
> >>Any reason this isn't using copy_node?
> >
> >No idea, perhaps that would be even better.  Jason?
> 
> I imagine that the code is trying to avoid copying lang-specific information
> to the artificial as-base type, but I don't see why copying that would be a
> problem.  Try copy_node and see if anything breaks?

This passed bootstrap/regtest on x86_64-linux and i686-linux, ok for trunk?

2016-01-08  Jakub Jelinek  <jakub@redhat.com>

	PR c++/69164
	* class.c (layout_class_type): Use copy_node to copy FIELD_DECLs.

	* g++.dg/opt/pr69164.C: New test.

--- gcc/cp/class.c.jj	2016-01-08 07:31:08.687172019 +0100
+++ gcc/cp/class.c	2016-01-08 15:16:49.946359971 +0100
@@ -6484,18 +6484,11 @@ layout_class_type (tree t, tree *virtual
       for (field = TYPE_FIELDS (t); field; field = DECL_CHAIN (field))
 	if (TREE_CODE (field) == FIELD_DECL)
 	  {
-	    *next_field = build_decl (input_location,
-				      FIELD_DECL,
-				      DECL_NAME (field),
-				      TREE_TYPE (field));
+	    *next_field = copy_node (field);
 	    DECL_CONTEXT (*next_field) = base_t;
-	    DECL_FIELD_OFFSET (*next_field) = DECL_FIELD_OFFSET (field);
-	    DECL_FIELD_BIT_OFFSET (*next_field)
-	      = DECL_FIELD_BIT_OFFSET (field);
-	    DECL_SIZE (*next_field) = DECL_SIZE (field);
-	    DECL_MODE (*next_field) = DECL_MODE (field);
 	    next_field = &DECL_CHAIN (*next_field);
 	  }
+      *next_field = NULL_TREE;
 
       /* Record the base version of the type.  */
       CLASSTYPE_AS_BASE (t) = base_t;
--- gcc/testsuite/g++.dg/opt/pr69164.C.jj	2016-01-08 15:14:43.769109468 +0100
+++ gcc/testsuite/g++.dg/opt/pr69164.C	2016-01-08 15:14:43.769109468 +0100
@@ -0,0 +1,30 @@
+// PR c++/69164
+// { dg-do compile { target c++11 } }
+// { dg-options "-O2" }
+
+struct A {
+  struct B {
+    B () {}
+    bool : 1;
+  };
+  B foo () { B r; return r; }
+};
+
+struct C {
+  struct D {
+    D (C *x) : d (x->c.foo ()) {}
+    A::B d;
+  };
+  A c;
+};
+
+struct F : C {
+  D f = this;
+  F (int, int) {}
+};
+
+void
+bar (int a, int b)
+{
+  F (b, a);
+}


	Jakub



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