===================================================================
@@ -21424,14 +21424,15 @@ output_cbranch (rtx op, const char *labe
/* PROB is the difference from 50%. */
int prob = XINT (note, 0) - REG_BR_PROB_BASE / 2;
- /* Only hint for highly probable/improbable branches on newer
- cpus as static prediction overrides processor dynamic
- prediction. For older cpus we may as well always hint, but
+ /* Only hint for highly probable/improbable branches on newer cpus when
+ we have real profile data, as static prediction overrides processor
+ dynamic prediction. For older cpus we may as well always hint, but
assume not taken for branches that are very close to 50% as a
mispredicted taken branch is more expensive than a
mispredicted not-taken branch. */
if (rs6000_always_hint
|| (abs (prob) > REG_BR_PROB_BASE / 100 * 48
+ && (profile_status_for_fn (cfun) != PROFILE_GUESSED)
&& br_prob_note_reliable_p (note)))
{
if (abs (prob) > REG_BR_PROB_BASE / 20