diff options
Diffstat (limited to 'gcc/predict.c')
| -rw-r--r-- | gcc/predict.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/gcc/predict.c b/gcc/predict.c index d9c7249..68b1113 100644 --- a/gcc/predict.c +++ b/gcc/predict.c @@ -4481,6 +4481,43 @@ force_edge_cold (edge e, bool impossible) } } +/* Change E's probability to NEW_E_PROB, redistributing the probabilities + of other outgoing edges proportionally. + + Note that this function does not change the profile counts of any + basic blocks. The caller must do that instead, using whatever + information it has about the region that needs updating. */ + +void +change_edge_frequency (edge e, profile_probability new_e_prob) +{ + profile_probability old_e_prob = e->probability; + profile_probability old_other_prob = old_e_prob.invert (); + profile_probability new_other_prob = new_e_prob.invert (); + + e->probability = new_e_prob; + profile_probability cumulative_prob = new_e_prob; + + unsigned int num_other = EDGE_COUNT (e->src->succs) - 1; + edge other_e; + edge_iterator ei; + FOR_EACH_EDGE (other_e, ei, e->src->succs) + if (other_e != e) + { + num_other -= 1; + if (num_other == 0) + /* Ensure that the probabilities add up to 1 without + rounding error. */ + other_e->probability = cumulative_prob.invert (); + else + { + other_e->probability /= old_other_prob; + other_e->probability *= new_other_prob; + cumulative_prob += other_e->probability; + } + } +} + #if CHECKING_P namespace selftest { |