https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63432
H.J. Lu <hjl.tools at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2014-10-03
Ever confirmed|0 |1
--- Comment #8 from H.J. Lu <hjl.tools at gmail dot com> ---
Bug is in
static void
recompute_probabilities (basic_block bb)
{
edge esucc;
edge_iterator ei;
FOR_EACH_EDGE (esucc, ei, bb->succs)
{
if (bb->count)
esucc->probability = GCOV_COMPUTE_SCALE (esucc->count,
bb->count);
if (esucc->probability > REG_BR_PROB_BASE)
{
We got
(gdb) whatis esucc->probability
type = int
(gdb) p esucc->count
$7 = 2822215
(gdb) p bb->count
$8 = 1
(gdb) p esucc->probability
$9 = -1842621072
(gdb)
When count is set from frequency scaled up by REG_BR_PROB_BASE,
probability may overflow.
