diff options
Diffstat (limited to 'gcc/tree-ssa-threadupdate.c')
| -rw-r--r-- | gcc/tree-ssa-threadupdate.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/gcc/tree-ssa-threadupdate.c b/gcc/tree-ssa-threadupdate.c index 610e80792d3..72fc5f897ad 100644 --- a/gcc/tree-ssa-threadupdate.c +++ b/gcc/tree-ssa-threadupdate.c @@ -254,6 +254,11 @@ struct ssa_local_info_t /* Blocks duplicated for the thread. */ bitmap duplicate_blocks; + + /* When we have multiple paths through a joiner which reach different + final destinations, then we may need to correct for potential + profile insanities. */ + bool need_profile_correction; }; /* Passes which use the jump threading code register jump threading @@ -827,7 +832,8 @@ compute_path_counts (struct redirection_data *rd, So ensure that this path's path_out_count is at least the difference between elast->count and nonpath_count. Otherwise the edge counts after threading will not be sane. */ - if (has_joiner && path_out_count < elast->count - nonpath_count) + if (local_info->need_profile_correction + && has_joiner && path_out_count < elast->count - nonpath_count) { path_out_count = elast->count - nonpath_count; /* But neither can we go above the minimum count along the path @@ -1496,6 +1502,7 @@ thread_block_1 (basic_block bb, bool noloop_only, bool joiners) ssa_local_info_t local_info; local_info.duplicate_blocks = BITMAP_ALLOC (NULL); + local_info.need_profile_correction = false; /* To avoid scanning a linear array for the element we need we instead use a hash table. For normal code there should be no noticeable @@ -1506,6 +1513,7 @@ thread_block_1 (basic_block bb, bool noloop_only, bool joiners) /* Record each unique threaded destination into a hash table for efficient lookups. */ + edge last = NULL; FOR_EACH_EDGE (e, ei, bb->preds) { if (e->aux == NULL) @@ -1559,6 +1567,17 @@ thread_block_1 (basic_block bb, bool noloop_only, bool joiners) /* Insert the outgoing edge into the hash table if it is not already in the hash table. */ lookup_redirection_data (e, INSERT); + + /* When we have thread paths through a common joiner with different + final destinations, then we may need corrections to deal with + profile insanities. See the big comment before compute_path_counts. */ + if ((*path)[1]->type == EDGE_COPY_SRC_JOINER_BLOCK) + { + if (!last) + last = e2; + else if (e2 != last) + local_info.need_profile_correction = true; + } } /* We do not update dominance info. */ |