This patch fixes the PR23623 regression. In conjunction with part 2 of
the series, it also fixes the new volatile-bitfields-3.c test case.
As I noted in previous discussion, there might be a better place to
accomplish this effect, but hacking DECL_BIT_FIELD_REPRESENTATIVE can't
work because the volatile-ness may be coming from a qualifier on the
pointer or object from which the field is being extracted, rather than
from a volatile qualifier on the bit field decl. I think the choices
are to do it in get_bit_range (as in this patch), in the callers of
get_bit_range, or at the places where the bit range information is being
used.
-Sandra
2013-06-16 Sandra Loosemore <san...@codesourcery.com>
PR middle-end/23623
gcc/
* expr.c (get_bit_range): Handle flag_strict_volatile_bitfields.
Index: gcc/expr.c
===================================================================
--- gcc/expr.c (revision 199963)
+++ gcc/expr.c (working copy)
@@ -4508,6 +4508,16 @@ get_bit_range (unsigned HOST_WIDE_INT *b
gcc_assert (TREE_CODE (exp) == COMPONENT_REF);
+ /* If -fstrict-volatile-bitfields was given and this is a volatile
+ access, then we must ignore any DECL_BIT_FIELD_REPRESENTATIVE and
+ do the access in the mode of the field. */
+ if (TREE_THIS_VOLATILE (exp)
+ && flag_strict_volatile_bitfields > 0)
+ {
+ *bitstart = *bitend = 0;
+ return;
+ }
+
field = TREE_OPERAND (exp, 1);
repr = DECL_BIT_FIELD_REPRESENTATIVE (field);
/* If we do not have a DECL_BIT_FIELD_REPRESENTATIVE there is no
