diff options
| author | daney <daney@138bc75d-0d04-0410-961f-82ee72b054a4> | 2009-07-25 20:25:18 +0000 |
|---|---|---|
| committer | daney <daney@138bc75d-0d04-0410-961f-82ee72b054a4> | 2009-07-25 20:25:18 +0000 |
| commit | c4d13c5c0535f2eba2ab5b5dee94666ff6dc7e60 (patch) | |
| tree | 697b3a3928c509ec1d15830956e5fd590de886f9 /gcc/cfgcleanup.c | |
| parent | 616b875f3e877e13c8ed17204b2c208bd6769e31 (diff) | |
2009-07-25 David Daney <ddaney@caviumnetworks.com>
PR rtl-optimization/40445
* emit-rtl.c (next_nonnote_insn_bb): New function.
* rtl.h (next_nonnote_insn_bb): Declare new function.
* cfgcleanup.c (try_optimize_cfg): Don't remove an empty block
with no successors that is the successor of the ENTRY_BLOCK.
Continue from the top after removing an empty fallthrough block.
* cfgrtl.c (get_last_bb_insn): Call next_nonnote_insn_bb instead
of next_nonnote_insn.
2009-07-25 David Daney <ddaney@caviumnetworks.com>
PR rtl-optimization/40445
* g++.dg/other/builtin-unreachable-1.C: New testcase.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@150090 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/cfgcleanup.c')
| -rw-r--r-- | gcc/cfgcleanup.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c index 01ddf999ed3..c631907799e 100644 --- a/gcc/cfgcleanup.c +++ b/gcc/cfgcleanup.c @@ -1846,10 +1846,16 @@ try_optimize_cfg (int mode) /* Delete trivially dead basic blocks. This is either blocks with no predecessors, or empty blocks with no - successors. Empty blocks may result from expanding + successors. However if the empty block with no + successors is the successor of the ENTRY_BLOCK, it is + kept. This ensures that the ENTRY_BLOCK will have a + successor which is a precondition for many RTL + passes. Empty blocks may result from expanding __builtin_unreachable (). */ if (EDGE_COUNT (b->preds) == 0 - || (EDGE_COUNT (b->succs) == 0 && BB_HEAD (b) == BB_END (b))) + || (EDGE_COUNT (b->succs) == 0 + && BB_HEAD (b) == BB_END (b) + && single_succ_edge (ENTRY_BLOCK_PTR)->dest != b)) { c = b->prev_bb; if (dump_file) @@ -1921,6 +1927,7 @@ try_optimize_cfg (int mode) delete_basic_block (b); changed = true; b = c; + continue; } if (single_succ_p (b) |