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| author | Josef Zlomek <zlomek@matfyz.cz> | 2001-12-21 02:50:10 +0100 |
|---|---|---|
| committer | Richard Henderson <rth@gcc.gnu.org> | 2001-12-20 17:50:10 -0800 |
| commit | b09d108b488516d1fc8225ab460799d5e8c6dab9 (patch) | |
| tree | 32379513001dec81f4dca82b4d14e1161d02c07c | |
| parent | f350566bf47f2584ccb8a7671ad6ffd4aa82a6b5 (diff) | |
| download | gcc-b09d108b488516d1fc8225ab460799d5e8c6dab9.zip gcc-b09d108b488516d1fc8225ab460799d5e8c6dab9.tar.gz gcc-b09d108b488516d1fc8225ab460799d5e8c6dab9.tar.bz2 | |
cfgloop.c (flow_loops_find): Use the information of the depth first search order of the CFG correctly when...
* cfgloop.c (flow_loops_find): Use the information of the depth
first search order of the CFG correctly when finding natural loops.
From-SVN: r48227
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/cfgloop.c | 28 |
2 files changed, 19 insertions, 14 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 5caed01..0db4281 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2001-12-20 Josef Zlomek <zlomek@matfyz.cz> + + * cfgloop.c (flow_loops_find): Use the information of the depth + first search order of the CFG correctly when finding natural loops. + 2001-12-20 Richard Henderson <rth@redhat.com> * config/alpha/alpha.md (prologue_mcount): Update for explicit relocs. diff --git a/gcc/cfgloop.c b/gcc/cfgloop.c index cabd2f2..a94cbfe 100644 --- a/gcc/cfgloop.c +++ b/gcc/cfgloop.c @@ -737,26 +737,26 @@ flow_loops_find (loops, flags) /* Find and record information about all the natural loops in the CFG. */ num_loops = 0; - for (b = 0; b < n_basic_blocks; b++) + for (b = n_basic_blocks - 1; b >= 0; b--) { - basic_block header; + basic_block latch; /* Search the nodes of the CFG in reverse completion order so that we can find outer loops first. */ - header = BASIC_BLOCK (rc_order[b]); + latch = BASIC_BLOCK (rc_order[b]); - /* Look for all the possible latch blocks for this header. */ - for (e = header->pred; e; e = e->pred_next) + /* Look for all the possible headers for this latch block. */ + for (e = latch->succ; e; e = e->succ_next) { - basic_block latch = e->src; - - /* Look for back edges where a predecessor is dominated - by this block. A natural loop has a single entry - node (header) that dominates all the nodes in the - loop. It also has single back edge to the header - from a latch node. Note that multiple natural loops - may share the same header. */ - if (latch != ENTRY_BLOCK_PTR + basic_block header = e->dest; + + /* Look for forward edges where this block is dominated by + a successor of this block. A natural loop has a single + entry node (header) that dominates all the nodes in the + loop. It also has single back edge to the header from a + latch node. Note that multiple natural loops may share + the same header. */ + if (header != EXIT_BLOCK_PTR && TEST_BIT (dom[latch->index], header->index)) { struct loop *loop; |