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| author | Richard Sandiford <richard.sandiford@arm.com> | 2015-11-07 09:56:04 +0000 |
|---|---|---|
| committer | Richard Sandiford <rsandifo@gcc.gnu.org> | 2015-11-07 09:56:04 +0000 |
| commit | f127ea514dbd61dde99f6d86c05d753748b9f93e (patch) | |
| tree | e6991c90c6ee33ae4de032d5acba2f29c1da2872 /gcc/tree-call-cdce.c | |
| parent | 88419b5295091e664e993fc6d981b3fb149a3e7b (diff) | |
| download | gcc-f127ea514dbd61dde99f6d86c05d753748b9f93e.zip gcc-f127ea514dbd61dde99f6d86c05d753748b9f93e.tar.gz gcc-f127ea514dbd61dde99f6d86c05d753748b9f93e.tar.bz2 | |
Try to update dominance info in tree-call-cdce.c
The pass would free the dominance info after making a change, but it
should be pretty easy to keep the information up-to-date when the call
has no EH edges.
Tested on x86_64-linux-gnu, arm-linux-gnueabi and aarch64-linux-gnu.
gcc/
* tree-call-cdce.c (shrink_wrap_one_built_in_call): Try to update
the dominance info; free it if we can't.
(pass_call_cdce::execute): Don't free the dominance info here.
From-SVN: r229916
Diffstat (limited to 'gcc/tree-call-cdce.c')
| -rw-r--r-- | gcc/tree-call-cdce.c | 37 |
1 files changed, 36 insertions, 1 deletions
diff --git a/gcc/tree-call-cdce.c b/gcc/tree-call-cdce.c index ffc1c4e..a5f38ce 100644 --- a/gcc/tree-call-cdce.c +++ b/gcc/tree-call-cdce.c @@ -731,6 +731,32 @@ shrink_wrap_one_built_in_call (gcall *bi_call) if (nconds == 0) return false; + /* The cfg we want to create looks like this: + + [guard n-1] <- guard_bb (old block) + | \ + | [guard n-2] } + | / \ } + | / ... } new blocks + | / [guard 0] } + | / / | } + [ call ] | <- bi_call_bb } + | \ | + | \ | + | [ join ] <- join_tgt_bb (old iff call must end bb) + | + possible EH edges (only if [join] is old) + + When [join] is new, the immediate dominators for these blocks are: + + 1. [guard n-1]: unchanged + 2. [call]: [guard n-1] + 3. [guard m]: [guard m+1] for 0 <= m <= n-2 + 4. [join]: [guard n-1] + + We punt for the more complex case case of [join] being old and + simply free the dominance info. We also punt on postdominators, + which aren't expected to be available at this point anyway. */ bi_call_bb = gimple_bb (bi_call); /* Now find the join target bb -- split bi_call_bb if needed. */ @@ -741,6 +767,7 @@ shrink_wrap_one_built_in_call (gcall *bi_call) join_tgt_in_edge_from_call = find_fallthru_edge (bi_call_bb->succs); if (join_tgt_in_edge_from_call == NULL) return false; + free_dominance_info (CDI_DOMINATORS); } else join_tgt_in_edge_from_call = split_block (bi_call_bb, bi_call); @@ -820,6 +847,15 @@ shrink_wrap_one_built_in_call (gcall *bi_call) guard_bb_in_edge->count = guard_bb->count - bi_call_in_edge->count; } + if (dom_info_available_p (CDI_DOMINATORS)) + { + /* The split_blocks leave [guard 0] as the immediate dominator + of [call] and [call] as the immediate dominator of [join]. + Fix them up. */ + set_immediate_dominator (CDI_DOMINATORS, bi_call_bb, guard_bb); + set_immediate_dominator (CDI_DOMINATORS, join_tgt_bb, guard_bb); + } + if (dump_file && (dump_flags & TDF_DETAILS)) { location_t loc; @@ -927,7 +963,6 @@ pass_call_cdce::execute (function *fun) if (something_changed) { - free_dominance_info (CDI_DOMINATORS); free_dominance_info (CDI_POST_DOMINATORS); /* As we introduced new control-flow we need to insert PHI-nodes for the call-clobbers of the remaining call. */ |