On Thu, Mar 03, 2016 at 03:15:41PM +0100, Marek Polacek wrote:
> This is ICE on invalid Cilk+ code. cilk_spawn expects a function call, so
> e.g.
> _Cilk_spawn (void) is invalid. The function call after the cilk_spawn keyword
> is parsed using recursive call in c_parser_postfix_expression (case
> RID_CILK_SPAWN). Now, c_parser_postfix_expression sees '(' followed by a
> typename, so it thinks we're inside a compound literal, which means it expects
> '{', but that isn't there, so we crash on the assert in c_parser_braced_init:
> gcc_assert (c_parser_next_token_is (parser, CPP_OPEN_BRACE));
> But as the comment in c_parser_postfix_expression says, the code for parsing
> a compound literal here is likely dead. I made an experiment and added
> gcc_unreachable () in that block, ran regtest, and there were no failures.
> Thus it should be safe to just remove the code, which also fixes this ICE;
> with
> the patch we just give a proper error and don't crash anymore.
>
> Bootstrapped/regtested on x86_64-linux, ok for trunk? I'm actually slightly
> nervous about the change, so maybe better table until gcc7?
This reminds me of PR67495. Perhaps the answer here is also during the
_Cilk* stuff parsing don't call c_parser_postfix_expression, but call
c_parser_cast_expression instead and then verify what it got?
> 2016-03-03 Marek Polacek <pola...@redhat.com>
>
> PR c/69798
> * c-parser.c (c_parser_postfix_expression): Remove code dealing with
> compound literals.
>
> * gcc.dg/cilk-plus/pr69798-1.c: New test.
> * gcc.dg/cilk-plus/pr69798-2.c: New test.
Jakub
