2004-07-08 Joseph S. Myers <jsm@polyomino.org.uk>

            Neil Booth  <neil@daikokuya.co.uk>

	PR c/2511
	PR c/3325
	* c-decl.c (finish_struct): Ensure bit-fields are given the
	correct type.
	* c-common.c (c_common_signed_or_unsigned_type): For C, require
	the precision to match as well as the mode.
	* expr.c (reduce_to_bit_field_precision): New function.
	(expand_expr_real_1): Reduce expressions of bit-field type to
	proper precision.
	* langhooks.h (reduce_bit_field_operations): New hook.
	* langhooks-def.h (LANG_HOOKS_REDUCE_BIT_FIELD_OPERATIONS):
	Define.
	* c-lang.c, objc/objc-lang.c
	(LANG_HOOKS_REDUCE_BIT_FIELD_OPERATIONS): Define.
	* objc/objc-act.c (check_ivars): Convert types to bit-field types
	before checking.
	* tree.c (build_nonstandard_integer_type): New function.
	* tree.h (build_nonstandard_integer_type): New prototype.
	* tree-ssa.c (tree_ssa_useless_type_conversion_1): Don't treat
	conversions between integer and boolean types as useless.

testsuite:
	* gcc.c-torture/execute/bitfld-1.x: Remove.
	* gcc.c-torture/execute/bitfld-3.c: New test.
	* gcc.dg/bitfld-2.c: Remove XFAILs.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@84279 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 28 insertions, 17 deletions

diff --git a/gcc/c-common.c b/gcc/c-common.c
index 9a8039b9431..ebb5e65e404 100644
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -1636,40 +1636,51 @@ c_common_signed_or_unsigned_type (int unsignedp, tree type)
       || TYPE_UNSIGNED (type) == unsignedp)
     return type;
 
-  /* Must check the mode of the types, not the precision.  Enumeral types
-     in C++ have precision set to match their range, but may use a wider
-     mode to match an ABI.  If we change modes, we may wind up with bad
-     conversions.  */
-
-  if (TYPE_MODE (type) == TYPE_MODE (signed_char_type_node))
+  /* For ENUMERAL_TYPEs in C++, must check the mode of the types, not
+     the precision; they have precision set to match their range, but
+     may use a wider mode to match an ABI.  If we change modes, we may
+     wind up with bad conversions.  For INTEGER_TYPEs in C, must check
+     the precision as well, so as to yield correct results for
+     bit-field types.  C++ does not have these separate bit-field
+     types, and producing a signed or unsigned variant of an
+     ENUMERAL_TYPE may cause other problems as well.  */
+
+#define TYPE_OK(node)							    \
+  (TYPE_MODE (type) == TYPE_MODE (node)					    \
+   && (c_dialect_cxx () || TYPE_PRECISION (type) == TYPE_PRECISION (node)))
+  if (TYPE_OK (signed_char_type_node))
     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
-  if (TYPE_MODE (type) == TYPE_MODE (integer_type_node))
+  if (TYPE_OK (integer_type_node))
     return unsignedp ? unsigned_type_node : integer_type_node;
-  if (TYPE_MODE (type) == TYPE_MODE (short_integer_type_node))
+  if (TYPE_OK (short_integer_type_node))
     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
-  if (TYPE_MODE (type) == TYPE_MODE (long_integer_type_node))
+  if (TYPE_OK (long_integer_type_node))
     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
-  if (TYPE_MODE (type) == TYPE_MODE (long_long_integer_type_node))
+  if (TYPE_OK (long_long_integer_type_node))
     return (unsignedp ? long_long_unsigned_type_node
 	    : long_long_integer_type_node);
-  if (TYPE_MODE (type) == TYPE_MODE (widest_integer_literal_type_node))
+  if (TYPE_OK (widest_integer_literal_type_node))
     return (unsignedp ? widest_unsigned_literal_type_node
 	    : widest_integer_literal_type_node);
 
 #if HOST_BITS_PER_WIDE_INT >= 64
-  if (TYPE_MODE (type) == TYPE_MODE (intTI_type_node))
+  if (TYPE_OK (intTI_type_node))
     return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
 #endif
-  if (TYPE_MODE (type) == TYPE_MODE (intDI_type_node))
+  if (TYPE_OK (intDI_type_node))
     return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
-  if (TYPE_MODE (type) == TYPE_MODE (intSI_type_node))
+  if (TYPE_OK (intSI_type_node))
     return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
-  if (TYPE_MODE (type) == TYPE_MODE (intHI_type_node))
+  if (TYPE_OK (intHI_type_node))
     return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
-  if (TYPE_MODE (type) == TYPE_MODE (intQI_type_node))
+  if (TYPE_OK (intQI_type_node))
     return unsignedp ? unsigned_intQI_type_node : intQI_type_node;
+#undef TYPE_OK
 
-  return type;
+  if (c_dialect_cxx ())
+    return type;
+  else
+    return build_nonstandard_integer_type (TYPE_PRECISION (type), unsignedp);
 }
 
 /* The C version of the register_builtin_type langhook.  */