| Message ID | cc2fc413-52e8-bce7-40ae-cff7214c7269@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | avoid alignment error for attribute warn_if_not_aligned | expand |
On Tue, Dec 12, 2017 at 1:57 AM, Martin Sebor <msebor@gmail.com> wrote: > My enhancement to improve the detection of attribute collisions > introduced a regression of sorts in the g++.dg/pr53037-4.C test > on ia64. > > https://gcc.gnu.org/ml/gcc-testresults/2017-12/msg00672.html > > The regression hasn't been noticed anywhere else only because > all the other targets apparently have no low limit on function > alignment, whereas ia64 has a limit of 32. As a result of > the limit the i64 compiler would issue not one but two errors > for a function declaration with attribute warn_if_not_aligned > that specifies a value less than 32: > one for the attribute itself (because it's not allowed on > functions), > and another for the lower value. > > The attached patch fixes this by issuing the error only for > attribute aligned with a lower requirement but not attribute > warn_if_not_aligned. > > I tried to come up with a test for this that would fail on > other targets besides ia64 (those with no low bound on > function alignment) but couldn't find a way to do it. If > someone knows of a way I'd be glad to add a better test > than pr53037-4.C. Ok. Richard. > Martin
gcc/c-family/ChangeLog: * c-attribs.c (common_handle_aligned_attribute): Avoid issuing an error for attribute warn_if_not_aligned. diff --git a/gcc/c-family/c-attribs.c b/gcc/c-family/c-attribs.c index 186df05..74c971d 100644 --- a/gcc/c-family/c-attribs.c +++ b/gcc/c-family/c-attribs.c @@ -1886,14 +1886,17 @@ common_handle_aligned_attribute (tree *node, tree name, tree args, int flags, curalign /= BITS_PER_UNIT; bitalign /= BITS_PER_UNIT; + bool diagd = true; if (DECL_USER_ALIGN (decl) || DECL_USER_ALIGN (last_decl)) - warning (OPT_Wattributes, - "ignoring attribute %<%E (%u)%> because it conflicts with " - "attribute %<%E (%u)%>", name, bitalign, name, curalign); - else + diagd = warning (OPT_Wattributes, + "ignoring attribute %<%E (%u)%> because it conflicts " + "with attribute %<%E (%u)%>", + name, bitalign, name, curalign); + else if (!warn_if_not_aligned_p) + /* Do not error out for attribute warn_if_not_aligned. */ error ("alignment for %q+D must be at least %d", decl, curalign); - if (note) + if (diagd && note) inform (DECL_SOURCE_LOCATION (last_decl), "previous declaration here"); *no_add_attrs = true;