Bug#608539: clang -ftrapv: UNREACHABLE on 64-bit off_t addition

[Jonathan Nieder]

Package: clang
Version: 2.7-3

$ cat csum-file.c
#define _FILE_OFFSET_BITS 64
#include <sys/types.h>

extern ssize_t xwrite(void);

void flush(off_t *total)
{
	*total += xwrite();
}
$ clang -c csum-file.c
$ clang -ftrapv -c csum-file.c
UNREACHABLE executed!
0  clang 0x08dc6ac8
Stack dump:
0.	Program arguments: /usr/bin/clang -cc1 -triple i386-pc-linux-gnu -S -disable-free -disable-llvm-verifier -main-file-name csum-file.c -mrelocation-model static -mdisable-fp-elim -mconstructor-aliases -target-cpu pentium4 -resource-dir /usr/lib/clang/1.1 -fmessage-length 0 -ftrapv -fgnu-runtime -fdiagnostics-show-option -o /tmp/cc-4ZBHFy.s -x c csum-file.c 
1.	<eof> parser at end of file
2.	Code generation
3.	Running pass 'X86 DAG->DAG Instruction Selection' on function '@flush'
clang: error: compiler command failed due to signal 6 (use -v to see invocation)

Ideas?