On 08/21/2017 06:21 AM, H.J. Lu wrote:
When warn_if_not_aligned_p is true, a warning will be issued on function declaration later. There is no need to warn function alignment when warn_if_not_aligned_p is true.OK for trunk? H.J. -- * c-attribs.c (common_handle_aligned_attribute): Don't warn function alignment if warn_if_not_aligned_p is true. --- gcc/c-family/c-attribs.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/gcc/c-family/c-attribs.c b/gcc/c-family/c-attribs.c index 5f79468407f..78969532543 100644 --- a/gcc/c-family/c-attribs.c +++ b/gcc/c-family/c-attribs.c @@ -1754,9 +1754,12 @@ common_handle_aligned_attribute (tree *node, tree args, int flags, This formally comes from the c++11 specification but we are doing it for the GNU attribute syntax as well. */ *no_add_attrs = true; - else if (TREE_CODE (decl) == FUNCTION_DECL + else if (!warn_if_not_aligned_p + && TREE_CODE (decl) == FUNCTION_DECL && DECL_ALIGN (decl) > (1U << i) * BITS_PER_UNIT) { + /* Don't warn function alignment here if warn_if_not_aligned_p is + true. It will be warned later. */ if (DECL_USER_ALIGN (decl)) error ("alignment for %q+D was previously specified as %d " "and may not be decreased", decl,
Your comment refers to warning but the code here uses error(). That raises two questions for me: a) will the later diagnostic really be a warning or an error, and if a warning, under what option will it be issued? and b) why is an error appropriate here when a warning is appropriate elsewhere (most other attribute conflicts are at present diagnosed with -Wattributes). My main motivation for these questions is to understand the rationale for warning for vs rejecting conflicts so that a consistent general solution can be implemented for all attributes (i.e., along the lines of my patch here: https://gcc.gnu.org/ml/gcc-patches/2017-08/msg01457.html) Martin
