Re: [PATCH] proposed fix for bug # 61144

[Jeff Law <law@redhat.com>]

On 05/21/14 21:59, Rich Felker wrote:
> On Wed, May 21, 2014 at 11:17:53AM +0200, Richard Biener wrote:
>> On Wed, May 21, 2014 at 3:59 AM, Rich Felker <dalias@libc.org> wrote:
>>> Bug # 61144 is a regression in 4.9.0 that breaks building of musl libc
>>> due to aggressive and semantically-incorrect constant folding of weak
>>> aliases. The attached patch seems to fix the issue. A weak alias
>>> should never be a candidate for constant folding because it may always
>>> be replaced by a strong definition from another translation unit.
>>>
>>> For details see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61144
>>>
>>> I do not have a copyright assignment on file but this patch should be
>>> sufficiently trivial not to require it.
>>
>> Please add a testcase.  Also I wonder why it isn't better to generalize
>
> How should a testcase be done? On the PR there's a testcase that shows
> the problem in the generated code, but no automated check for it.
> Testing this is actually a bit of a pain unless you're allowed to run
> the generated program.
You can run the test program.  Have it exit (0) on success, abort () on 
failure if at all possible.  Then drop the test source file into 
gcc/testsuite/gcc.c-torture/execute/pr61144.c

At least that's the easiest way when you don't need to pass special 
arguments, restrict it to certain targets, etc.

Jeff