PR69502 notes that the documentation of the align type attribute had
gotten out of sync with the corresponding variable attribute with
respect to whether decreasing the alignment of a type was permitted.
I've checked in this patch to replace the incorrect paragraph with a
copy of the correct one.
-Sandra
2018-11-11 Sandra Loosemore <san...@codesourcery.com>
PR c/69502
gcc/
* doc/extend.texi (Common Type Attributes): For the align type
attribute, copy language about decreasing alignment from the
corresponding variable attribute.
Index: gcc/doc/extend.texi
===================================================================
--- gcc/doc/extend.texi (revision 266023)
+++ gcc/doc/extend.texi (working copy)
@@ -7101,8 +7101,11 @@ up to a maximum of 8-byte alignment, the
in an @code{__attribute__} still only provides you with 8-byte
alignment. See your linker documentation for further information.
-The @code{aligned} attribute can only increase alignment. Alignment
-can be decreased by specifying the @code{packed} attribute. See below.
+When used on a struct, or struct member, the @code{aligned} attribute can
+only increase the alignment; in order to decrease it, the @code{packed}
+attribute must be specified as well. When used as part of a typedef, the
+@code{aligned} attribute can both increase and decrease alignment, and
+specifying the @code{packed} attribute generates a warning.
@cindex @code{warn_if_not_aligned} type attribute
@item warn_if_not_aligned (@var{alignment})
