re PR c++/27292 (ICE on casts on bitfields)

	PR c++/27292
	* typeck.c (decay_conversion): Don't adjust bitfield types.
	(perform_integral_promotions): Treat bitfield enums as enums, not
	as short integer types.
	* tree.c (rvalue): Convert bitfields to their correct types.
	PR c++/27292
	* g++.dg/conversion/bitfield1.C: New test.
	* g++.dg/conversion/bitfield2.C: Likewise.
	* g++.dg/conversion/bitfield3.C: Likewise.

From-SVN: r113240

7 files changed, 67 insertions, 7 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index fe48ced..494bdef 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,11 @@
+2006-04-24  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/27292
+	* typeck.c (decay_conversion): Don't adjust bitfield types.
+	(perform_integral_promotions): Treat bitfield enums as enums, not
+	as short integer types.
+	* tree.c (rvalue): Convert bitfields to their correct types.
+
 2006-04-24  Volker Reichelt  <reichelt@igpm.rwth-aachen.de>
 
 	PR c++/19963
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index d58b5b3..a956205 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -371,7 +371,9 @@ rvalue (tree expr)
   tree type;
   if (real_lvalue_p (expr))
     {
-      type = TREE_TYPE (expr);
+      type = is_bitfield_expr_with_lowered_type (expr);
+      if (!type)
+	type = TREE_TYPE (expr);
       /* [basic.lval]
 	 
          Non-class rvalues always have cv-unqualified types.  */
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 7fc6cab..394a4ec 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -1435,7 +1435,6 @@ tree
 decay_conversion (tree exp)
 {
   tree type;
-  tree bitfield_type;
   enum tree_code code;
 
   type = TREE_TYPE (exp);
@@ -1448,10 +1447,6 @@ decay_conversion (tree exp)
       return error_mark_node;
     }
 
-  bitfield_type = is_bitfield_expr_with_lowered_type (exp);
-  if (bitfield_type) 
-    exp = build_nop (bitfield_type, exp);
-
   exp = decl_constant_value (exp);
 
   /* build_c_cast puts on a NOP_EXPR to make the result not an lvalue.
@@ -1533,7 +1528,13 @@ perform_integral_promotions (tree expr)
   tree type;
   tree promoted_type;
 
-  type = TREE_TYPE (expr);
+  /* [conv.prom]
+
+     If the bitfield has an enumerated type, it is treated as any
+     other value of that type for promotion purposes.  */
+  type = is_bitfield_expr_with_lowered_type (expr);
+  if (!type || TREE_CODE (type) != ENUMERAL_TYPE)
+    type = TREE_TYPE (expr);
   gcc_assert (INTEGRAL_OR_ENUMERATION_TYPE_P (type));
   promoted_type = type_promotes_to (type);
   if (type != promoted_type)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e6096c1..abad315 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2006-04-24  Mark Mitchell  <mark@codesourcery.com>
+
+	PR c++/27292
+	* g++.dg/conversion/bitfield1.C: New test.
+	* g++.dg/conversion/bitfield2.C: Likewise.
+	* g++.dg/conversion/bitfield3.C: Likewise.
+
 2006-04-24  Andrew Pinski  <pinskia@gcc.gnu.org>
 	Richard Guenther  <rguenther@suse.de>
 
diff --git a/gcc/testsuite/g++.dg/conversion/bitfield1.C b/gcc/testsuite/g++.dg/conversion/bitfield1.C
new file mode 100644
index 0000000..a660e79
--- /dev/null
+++ b/gcc/testsuite/g++.dg/conversion/bitfield1.C
@@ -0,0 +1,17 @@
+// { dg-do run }
+// { dg-options "-w" }
+
+enum E { a, b = 1LL << 48 };
+ 
+struct S {
+  E e : 3;
+};
+
+S s;
+
+int main () {
+  if (sizeof (E) != sizeof (long long))
+    return 1;
+  if (sizeof (s.e + 3) != sizeof (long long))
+    return 2;
+}
diff --git a/gcc/testsuite/g++.dg/conversion/bitfield2.C b/gcc/testsuite/g++.dg/conversion/bitfield2.C
new file mode 100644
index 0000000..aa60d35
--- /dev/null
+++ b/gcc/testsuite/g++.dg/conversion/bitfield2.C
@@ -0,0 +1,11 @@
+// PR c++/27292
+
+struct A
+{
+  int i : 8;
+};
+
+bool foo(A a)
+{
+  return int(a.i);
+}
diff --git a/gcc/testsuite/g++.dg/conversion/bitfield3.C b/gcc/testsuite/g++.dg/conversion/bitfield3.C
new file mode 100644
index 0000000..a897bf59
--- /dev/null
+++ b/gcc/testsuite/g++.dg/conversion/bitfield3.C
@@ -0,0 +1,14 @@
+// PR c++/16376
+// { dg-do run }
+
+int main(void){
+  struct bits {
+    unsigned int ui3 : 3;
+  } bits;
+  int i = -1;   /* is a very large positive number as unsigned */
+
+  bits.ui3 = 1u;
+  if( bits.ui3 < i )
+    return 1;
+  return 0;
+}