From e9f9692b8e2fc785122da79746837e7e42b39f7b Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Sat, 16 Jun 2007 00:33:01 +0700 Subject: [PATCH] extend.texi: Document behavior of __attribute__((aligned)) on typedefs. * doc/extend.texi: Document behavior of __attribute__((aligned)) on typedefs. From-SVN: r125747 --- gcc/ChangeLog | 5 +++++ gcc/doc/extend.texi | 7 +++++-- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index be3b820705c..72c8dbb3106 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2007-06-15 Matthew Wilcox + + * doc/extend.texi: Document behavior of __attribute__((aligned)) + on typedefs. + 2007-06-15 Mark Mitchell * rtlanal.c (note_stores): Improve documentation. diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index baeff309adf..c957757be10 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -3153,8 +3153,11 @@ copy operations more efficient, because the compiler can use whatever instructions copy the biggest chunks of memory when performing copies to or from the variables or fields that you have aligned this way. -The @code{aligned} attribute can only increase the alignment; but you -can decrease it by specifying @code{packed} as well. 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 will generate a warning. Note that the effectiveness of @code{aligned} attributes may be limited by inherent limitations in your linker. On many systems, the linker is