Bug#686231: dragonegg-4.6: internal compiler error: Segmentation fault with llvm-gcc

[Vincent Lefevre]

reassign 686231 cpp-4.6
found 686231 4.6.3-9
thanks

On 2012-08-30 13:08:28 +0200, Vincent Lefevre wrote:
> Package: dragonegg-4.6
> Version: 3.1-2
> Severity: important
> 
> I get the following ICE on the following program:
> 
> int f (unsigned int u)
> {
>   unsigned int c;
>   __asm__ ("bsr %1,%0" : "=r" (c) : "rm" (u));
>   return 0;
> }
> 
> $ llvm-gcc -c test.i
> *** WARNING *** there are active plugins, do not report this as a bug unless you can reproduce it without enabling any plugins.
> Event                            | Plugins
> PLUGIN_FINISH_UNIT               | dragonegg
> PLUGIN_FINISH                    | dragonegg
> PLUGIN_START_UNIT                | dragonegg
> PLUGIN_ALL_IPA_PASSES_END        | dragonegg
> test.i: In function ‘f’:
> test.i:4:3: internal compiler error: Segmentation fault
> [...]
> 
> This is due to the dragonegg plugin, because gcc-4.6 alone is fine
> on this example.

Downgrading llvm-gcc / dragonegg doesn't solve the problem, while
it was working in the past. But downgrading the packages of gcc-4.6
source from 4.6.3-9 to 4.6.3-8 solves the problem. As valgrind
output shows that the crash occurs in

  /usr/lib/gcc/x86_64-linux-gnu/4.6/cc1

I assume that the bug is in cpp-4.6.

-- 
Vincent Lefèvre <vincent at vinc17.net> - Web: <http://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)