diff options
Diffstat (limited to 'gcc/profile.c')
| -rw-r--r-- | gcc/profile.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/gcc/profile.c b/gcc/profile.c index 3f48be623d2..39d0493c6dd 100644 --- a/gcc/profile.c +++ b/gcc/profile.c @@ -557,12 +557,24 @@ compute_branch_probabilities (void) num_branches++; } } - /* Otherwise distribute the probabilities evenly so we get sane - sum. Use simple heuristics that if there are normal edges, + /* Otherwise try to preserve the existing REG_BR_PROB probabilities + tree based profile guessing put into code. */ + else if (profile_status == PROFILE_ABSENT + && !ir_type () + && bb->succ && bb->succ->succ_next + && (note = find_reg_note (BB_END (bb), REG_BR_PROB, 0))) + { + int prob = INTVAL (XEXP (note, 0)); + + BRANCH_EDGE (bb)->probability = prob; + FALLTHRU_EDGE (bb)->probability = REG_BR_PROB_BASE - prob; + } + /* As a last resolt, distribute the probabilities evenly. + Use simple heuristics that if there are normal edges, give all abnormals frequency of 0, otherwise distribute the frequency over abnormals (this is the case of noreturn calls). */ - else + else if (profile_status == PROFILE_ABSENT) { int total = 0; |