Created attachm=
ent 105451 [details]
full backtrace from piglit crash

(In reply to comment #4)
> All the crashes are in the same place, right?
>=20
> Can you run it under gdb and print out n2 and the contents of
> g->nodes[n].adjacency_list (it's an array with g->nodes[n].adjac=
ency_count
> elements) after the segfault? How about the former before the ra_simpl=
ify()
> call in the ra_allocate() call that's segfaulting? (If you don't know =
how to
> do this, see
> http://stackoverflow.com/questions/2956889/how-to-set-a-cou=
nter-for-a-gdb-
> breakpoint)
>=20
> I'm guessing that it's segfaulting because n2 is some bogus value. n2 =
comes
> from the adjacency_list, which is something generated before the alloc=
ator
> actually runs by code I didn't touch and then never modified afterward=
, and
> the code that's segfaulting wasn't modified by the commit in question,=
 so
> the two most likely options I see are that either this is exposing a b=
ug
> somewhere else (like in r300g) or the new ra_simplify() is somehow
> corrupting the adjacency_list. I don't know how r300g sets up the regi=
ster
> conflicts and register classes, though, so I can't guess why it works =
fine
> on i965 but fails for r300g.

OK, so not sure if I know what I'm doing but selecting one random crashing
piglit test

/bin/shader_runner tests/shaders/glsl-fs-loop-continue.shader_test -auto

Program received signal SIGSEGV, Segmentation fault.
0xb76391a9 in ra_select (g=3D0x80c2058) at
../../src/mesa/program/register_allocate.c:525
525            BITSET_TEST(g->regs->regs[r].conflicts, g->nodes[n2=
].reg)) {

print n2
$2 =3D 0

print n
$7 =3D 1

print g->nodes[n].adjacency_count
$1 =3D 3

print g->nodes[n].adjacency_list
$3 =3D (unsigned int *) 0x80c1b58

print g->nodes[n].adjacency_list[0]
$4 =3D 1

print g->nodes[n].adjacency_list[1]
$5 =3D 0

print g->nodes[n].adjacency_list[2]
$6 =3D 2

full backtrace attached.