https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108623
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|other |middle-end
Target| |powerpc*
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
There are 15 spare bits at the end of the bits, a better solution is to
re-order things so precision remains aligned to 16 bits, for example by moving
the
6 bits adjacent to it to the "spare" and extending precision to a full 16 bits.
Like with the following which aligns all >1 bit fields to at least 8 bits
diff --git a/gcc/tree-core.h b/gcc/tree-core.h
index acd8deea34e..e5513208511 100644
--- a/gcc/tree-core.h
+++ b/gcc/tree-core.h
@@ -1686,18 +1686,8 @@ struct GTY(()) tree_type_common {
tree attributes;
unsigned int uid;
- unsigned int precision : 10;
- unsigned no_force_blk_flag : 1;
- unsigned needs_constructing_flag : 1;
- unsigned transparent_aggr_flag : 1;
- unsigned restrict_flag : 1;
- unsigned contains_placeholder_bits : 2;
-
+ unsigned int precision : 16;
ENUM_BITFIELD(machine_mode) mode : 8;
-
- /* TYPE_STRING_FLAG for INTEGER_TYPE and ARRAY_TYPE.
- TYPE_CXX_ODR_P for RECORD_TYPE and UNION_TYPE. */
- unsigned string_flag : 1;
unsigned lang_flag_0 : 1;
unsigned lang_flag_1 : 1;
unsigned lang_flag_2 : 1;
@@ -1713,12 +1703,22 @@ struct GTY(()) tree_type_common {
so we need to store the value 32 (not 31, as we need the zero
as well), hence six bits. */
unsigned align : 6;
+ /* TYPE_STRING_FLAG for INTEGER_TYPE and ARRAY_TYPE.
+ TYPE_CXX_ODR_P for RECORD_TYPE and UNION_TYPE. */
+ unsigned string_flag : 1;
+ unsigned no_force_blk_flag : 1;
+
unsigned warn_if_not_align : 6;
+ unsigned needs_constructing_flag : 1;
+ unsigned transparent_aggr_flag : 1;
+
+ unsigned contains_placeholder_bits : 2;
+ unsigned restrict_flag : 1;
unsigned typeless_storage : 1;
unsigned empty_flag : 1;
unsigned indivisible_p : 1;
unsigned no_named_args_stdarg_p : 1;
- unsigned spare : 15;
+ unsigned spare : 9;
alias_set_type alias_set;
tree pointer_to;
