[LLVMdev] ARM regression between r223766 and r223925

[Renato Golin]

On 13 December 2014 at 09:49, İsmail Dönmez <ismail at donmez.ws> wrote:
> With trunk things got even worse while compiling a simple hello world cpp:
>
> 1.      /usr/lib/gcc/arm-linux-gnueabihf/4.9/../../../../include/c++/4.9/bits/basic_string.h:114:57:
> current parser token 'other'
> 2.      /usr/lib/gcc/arm-linux-gnueabihf/4.9/../../../../include/c++/4.9/bits/basic_string.h:45:1:
> parsing namespace 'std'
> 3.      /usr/lib/gcc/arm-linux-gnueabihf/4.9/../../../../include/c++/4.9/bits/basic_string.h:112:5:
> parsing struct/union/class body 'basic_string'
> clang-3.6: error: unable to execute command: Bus error
>
> and dmesg agrees:
>
> [   96.272849] Alignment trap: not handling instruction f4400add at [<b4072ffc>]
> [   96.280467] Unhandled fault: alignment exception (0x801) at 0x01d7a8cc
>
> Might this be due to the fact that I now compile with -mfpu=neon ?

Ismail,

I'm really sorry for not looking into this when I should, you're
absolutely correct. Here's the bug:

http://llvm.org/bugs/show_bug.cgi?id=22375

I'm self-hosting the release r223766 and found many Clang segfaults,
though not *that* one. I went back (3000 commits) and found that
spotting the *right* failure is near impossible... So, I'm wondering
how did you come up with that range? Did you succeed in self-hosting
223766 with NEON?

cheers,
--renato