segfault with bitfields in structs

[Michael Walle <michael@walle.cc>]

>Submitter-Id:	net
>Originator:	Michael Walle
>Organization:	
>Confidential:	no
>Synopsis:	segfault with bitfields in structs
>Severity:	serious
>Priority:	medium
>Category:	c
>Class:		ice-on-legal-code
>Release:	gcc (Debian 4.3.2-1.1) 4.3.2
>Environment:
System: Linux thanatos 2.6.26-2-686-bigmem #1 SMP Thu Mar 26 02:03:34 UTC 2009 
i686 GNU/Linux
>Description:
	Compiling the following (nonsense but valid) code triggers an internal
	compiler error.
>How-To-Repeat:
	Compile the following:
	
	-- snip --
	struct s {
	    unsigned int a : 4;
	    unsigned int b : 28;
	};
	
	void f()
	{
	    char c;
	    struct s s;
	    s.a = (c >> 4) & ~(1<<4);
	}
	-- snip --

	$ gcc -Wall -c bug.c 
	gcc: Internal error: Segmentation fault (program cc1)
	Please submit a full bug report.
	See <file:///usr/share/doc/gcc-4.3/README.Bugs> for instructions.
>Fix:
	not known