re PR c++/27505 (ICE in const folding with bitfields)

	PR c++/27505
	* call.c (convert_like_real): Convert bitfields to their declared
	types when forming an rvalue.
	* tree.c (convert_bitfield_to_declared_type): New function.
	(rvalue): Use it.
	* cp-tree.h (convert_bitfield_to_declare_type): Declare it.
	PR c++/27505
	* g++.dg/expr/bitfield1.C: New test.

From-SVN: r113803

6 files changed, 46 insertions, 5 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 0d62953..3bdf214 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,12 @@
+2006-05-15  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/27505
+	* call.c (convert_like_real): Convert bitfields to their declared
+	types when forming an rvalue.
+	* tree.c (convert_bitfield_to_declared_type): New function.
+	(rvalue): Use it.
+	* cp-tree.h (convert_bitfield_to_declare_type): Declare it.
+
 2006-05-15  Volker Reichelt  <reichelt@igpm.rwth-aachen.de>
 
 	PR c++/27582
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 6743f92..a7cb22a 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -4328,6 +4328,7 @@ convert_like_real (conversion *convs, tree expr, tree fn, int argnum,
   switch (convs->kind)
     {
     case ck_rvalue:
+      expr = convert_bitfield_to_declared_type (expr);
       if (! IS_AGGR_TYPE (totype))
 	return expr;
       /* Else fall through.  */
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 2e5739a..8e56a9f 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -4335,6 +4335,7 @@ extern tree cp_add_pending_fn_decls		(void*,tree);
 extern int cp_auto_var_in_fn_p			(tree,tree);
 extern tree fold_if_not_in_template		(tree);
 extern tree rvalue                              (tree);
+extern tree convert_bitfield_to_declared_type   (tree);
    
 /* in typeck.c */
 extern int string_conv_p			(tree, tree, int);
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 60ba13f..bc8e737 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -362,22 +362,35 @@ get_target_expr (tree init)
   return build_target_expr_with_type (init, TREE_TYPE (init));
 }
 
+/* If EXPR is a bitfield reference, convert it to the declared type of
+   the bitfield, and return the resulting expression.  Otherwise,
+   return EXPR itself.  */
+
+tree
+convert_bitfield_to_declared_type (tree expr)
+{
+  tree bitfield_type;
+
+  bitfield_type = is_bitfield_expr_with_lowered_type (expr);
+  if (bitfield_type)
+    expr = cp_convert (TYPE_MAIN_VARIANT (bitfield_type), expr);
+  return expr;
+}
+
 /* EXPR is being used in an rvalue context.  Return a version of EXPR
    that is marked as an rvalue.  */
 
 tree
 rvalue (tree expr)
 {
-  tree type;
+  expr = convert_bitfield_to_declared_type (expr);
   if (real_lvalue_p (expr))
     {
-      type = is_bitfield_expr_with_lowered_type (expr);
-      if (type)
-	return cp_convert (TYPE_MAIN_VARIANT (type), expr);
-      type = TREE_TYPE (expr);
+      tree type;
       /* [basic.lval]
 	 
          Non-class rvalues always have cv-unqualified types.  */
+      type = TREE_TYPE (expr);
       if (!CLASS_TYPE_P (type))
 	type = TYPE_MAIN_VARIANT (type);
       expr = build1 (NON_LVALUE_EXPR, type, expr);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 771256a..529a209 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2006-05-15  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/27505
+	* g++.dg/expr/bitfield1.C: New test.
+
 2006-05-15  Richard Guenther  <rguenther@suse.de>
 
 	PR tree-optimization/27603
diff --git a/gcc/testsuite/g++.dg/expr/bitfield1.C b/gcc/testsuite/g++.dg/expr/bitfield1.C
new file mode 100644
index 0000000..f3d4741
--- /dev/null
+++ b/gcc/testsuite/g++.dg/expr/bitfield1.C
@@ -0,0 +1,12 @@
+// PR c++/27505
+
+struct s {
+  bool field:8;
+};
+
+void
+foo (struct s *p)
+{
+  if (!p->field)
+    ;
+}