diff options
author | Jan Hubicka <jh@suse.cz> | 2012-02-10 12:21:16 +0000 |
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committer | Jan Hubicka <jh@suse.cz> | 2012-02-10 12:21:16 +0000 |
commit | b1974ad8cd4105734ec0e3b5567a09f7dbb8e798 (patch) | |
tree | 5b6fdd5a22647ed052e64b528c984e777237ece1 /gcc/predict.c | |
parent | 2dfe2df5d281c3c69b8006709266c773f875196d (diff) |
PR middle-end/48600
* predict.c (predict_paths_for_bb): Prevent looping.
(predict_paths_leading_to_edge, predict_paths_leading_to): Update.
* g++.dg/torture/pr48600.C: New testcase.
git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@184089 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/predict.c')
-rw-r--r-- | gcc/predict.c | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/gcc/predict.c b/gcc/predict.c index 92365317905..67131c9e759 100644 --- a/gcc/predict.c +++ b/gcc/predict.c @@ -1827,7 +1827,8 @@ tree_estimate_probability_driver (void) static void predict_paths_for_bb (basic_block cur, basic_block bb, enum br_predictor pred, - enum prediction taken) + enum prediction taken, + bitmap visited) { edge e; edge_iterator ei; @@ -1848,7 +1849,7 @@ predict_paths_for_bb (basic_block cur, basic_block bb, continue; gcc_assert (bb == cur || dominated_by_p (CDI_POST_DOMINATORS, cur, bb)); - /* See if there is how many edge from e->src that is not abnormal + /* See if there is an edge from e->src that is not abnormal and does not lead to BB. */ FOR_EACH_EDGE (e2, ei2, e->src->succs) if (e2 != e @@ -1861,16 +1862,20 @@ predict_paths_for_bb (basic_block cur, basic_block bb, /* If there is non-abnormal path leaving e->src, predict edge using predictor. Otherwise we need to look for paths - leading to e->src. */ + leading to e->src. + + The second may lead to infinite loop in the case we are predicitng + regions that are only reachable by abnormal edges. We simply + prevent visiting given BB twice. */ if (found) predict_edge_def (e, pred, taken); - else - predict_paths_for_bb (e->src, e->src, pred, taken); + else if (!bitmap_set_bit (visited, e->src->index)) + predict_paths_for_bb (e->src, e->src, pred, taken, visited); } for (son = first_dom_son (CDI_POST_DOMINATORS, cur); son; son = next_dom_son (CDI_POST_DOMINATORS, son)) - predict_paths_for_bb (son, bb, pred, taken); + predict_paths_for_bb (son, bb, pred, taken, visited); } /* Sets branch probabilities according to PREDiction and @@ -1880,7 +1885,9 @@ static void predict_paths_leading_to (basic_block bb, enum br_predictor pred, enum prediction taken) { - predict_paths_for_bb (bb, bb, pred, taken); + bitmap visited = BITMAP_ALLOC (NULL); + predict_paths_for_bb (bb, bb, pred, taken, visited); + BITMAP_FREE (visited); } /* Like predict_paths_leading_to but take edge instead of basic block. */ @@ -1903,7 +1910,11 @@ predict_paths_leading_to_edge (edge e, enum br_predictor pred, break; } if (!has_nonloop_edge) - predict_paths_for_bb (bb, bb, pred, taken); + { + bitmap visited = BITMAP_ALLOC (NULL); + predict_paths_for_bb (bb, bb, pred, taken, visited); + BITMAP_FREE (visited); + } else predict_edge_def (e, pred, taken); } |