Steps to reproduce:

cat >> test.c <<EOF
__thread int foo;

void bar (void) {
  foo = 2;
}
EOF

hppa64-linux-gnu-gcc-4.3.1 -S test.c
test.c: In function 'bar':
test.c:5: error: unrecognizable insn:
(insn 6 5 7 3 test.c:4 (set (reg:DI 67)
        (unspec:SI [
                (const_int 0 [0x0])
            ] 3)) -1 (nil))
test.c:5: internal compiler error: in extract_insn, at recog.c:1990
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

Expected:
- Compiler correctly compiles the code.

Observed:
- ICE trying to compile code with __thread keyword.

hppa does have support for thread local storage, but it's never been tested on the 64-bit compiler.

I came across this error while trying to port glibc to hppa64-linux-gnu during a 64-bit userspace bring-up.