[Bug c/67279] -fsanitize=undefined spurious error: initializer element is not constant

["manu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67279

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-08-19
                 CC|                            |manu at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #4 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
The reason for the error is that -fsanitize=undefined replaces 1<<31 with a
call to a sanitizer function __ubsan_handle_shift_out_of_bounds(), however,
this function call is not constant and it cannot be the initializer of a static
variable.

A possible solution could be to give a warning enabled by default (about 1 <<
31 being undefined) and to NOT sanitize expressions that are required to be
constants (since anyway the compiler will not accept them).

In any case, it makes sense that -fsanitize=undefined does not affect whether
the code is compiled or not.
>From gcc-bugs-return-495230-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Wed Aug 19 20:26:00 2015
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Subject: [Bug target/67281] HTM builtins aren't treated as compiler barriers on powerpc
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67281

Peter Bergner <bergner at gcc dot gnu.org> changed:

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--- Comment #5 from Peter Bergner <bergner at gcc dot gnu.org> ---
(In reply to Tulio Magno Quites Machado Filho from comment #4)
> I disagree with you.

I agree with Tulio.


> Here's an example:
> 
> long
> foo (long dest, long *src0, long src1, long tries)
> {
>   long i;
>   for (i = 0; i < tries; i++)
>     {
>       __builtin_tbegin (0);
>       dest = *src0 + src1;
>       if (dest == 13)
> 	__builtin_tabort(0);
>       __builtin_tend (0);
>     }
>   return dest;
> }

Even better is to change src1 to a pointer too and dereference that within the
transaction.  If *src0 and *src1 are two memory locations that should be
updated together and atomically, then allowing them to move past the tbegin.
could break that requirement.
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Subject: [Bug c++/66606] missing diagnostic on using function main
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idf606

Ville Voutilainen <ville.voutilainen at gmail dot com> changed:

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----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-08-19
                 CC|                            |ville.voutilainen at gmail dot com
     Ever confirmed|0                           |1