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| author | Bin Cheng <bin.cheng@arm.com> | 2017-10-18 15:56:15 +0000 |
|---|---|---|
| committer | Bin Cheng <amker@gcc.gnu.org> | 2017-10-18 15:56:15 +0000 |
| commit | 85aa9ed64bf871b2e620211609855804e1775864 (patch) | |
| tree | 64a5269b9e0cf50625e2eb19ec76c7064588216e /gcc/tree-loop-distribution.c | |
| parent | e33507e33c20c23d4b72687ce5129dcc4c75f0be (diff) | |
| download | gcc-85aa9ed64bf871b2e620211609855804e1775864.zip gcc-85aa9ed64bf871b2e620211609855804e1775864.tar.gz gcc-85aa9ed64bf871b2e620211609855804e1775864.tar.bz2 | |
re PR tree-optimization/82574 (wrong code at -O3 on x86_64-linux-gnu)
PR tree-optimization/82574
* tree-loop-distribution.c (find_single_drs): New parameter. Check
that data reference must be executed exactly once per iteration
against the outermost loop in nest.
(classify_partition): Update call to above function.
gcc/testsuite
* gcc.dg/tree-ssa/pr82574.c: New test.
From-SVN: r253857
Diffstat (limited to 'gcc/tree-loop-distribution.c')
| -rw-r--r-- | gcc/tree-loop-distribution.c | 26 |
1 files changed, 15 insertions, 11 deletions
diff --git a/gcc/tree-loop-distribution.c b/gcc/tree-loop-distribution.c index 5e835be..6abb7e4 100644 --- a/gcc/tree-loop-distribution.c +++ b/gcc/tree-loop-distribution.c @@ -1283,12 +1283,12 @@ build_rdg_partition_for_vertex (struct graph *rdg, int v) return partition; } -/* Given PARTITION of RDG, record single load/store data references for - builtin partition in SRC_DR/DST_DR, return false if there is no such +/* Given PARTITION of LOOP and RDG, record single load/store data references + for builtin partition in SRC_DR/DST_DR, return false if there is no such data references. */ static bool -find_single_drs (struct graph *rdg, partition *partition, +find_single_drs (struct loop *loop, struct graph *rdg, partition *partition, data_reference_p *dst_dr, data_reference_p *src_dr) { unsigned i; @@ -1344,10 +1344,12 @@ find_single_drs (struct graph *rdg, partition *partition, && DECL_BIT_FIELD (TREE_OPERAND (DR_REF (single_st), 1))) return false; - /* Data reference must be executed exactly once per iteration. */ + /* Data reference must be executed exactly once per iteration of each + loop in the loop nest. We only need to check dominance information + against the outermost one in a perfect loop nest because a bb can't + dominate outermost loop's latch without dominating inner loop's. */ basic_block bb_st = gimple_bb (DR_STMT (single_st)); - struct loop *inner = bb_st->loop_father; - if (!dominated_by_p (CDI_DOMINATORS, inner->latch, bb_st)) + if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb_st)) return false; if (single_ld) @@ -1365,14 +1367,16 @@ find_single_drs (struct graph *rdg, partition *partition, /* Load and store must be in the same loop nest. */ basic_block bb_ld = gimple_bb (DR_STMT (single_ld)); - if (inner != bb_ld->loop_father) + if (bb_st->loop_father != bb_ld->loop_father) return false; - /* Data reference must be executed exactly once per iteration. */ - if (!dominated_by_p (CDI_DOMINATORS, inner->latch, bb_ld)) + /* Data reference must be executed exactly once per iteration. + Same as single_st, we only need to check against the outermost + loop. */ + if (!dominated_by_p (CDI_DOMINATORS, loop->latch, bb_ld)) return false; - edge e = single_exit (inner); + edge e = single_exit (bb_st->loop_father); bool dom_ld = dominated_by_p (CDI_DOMINATORS, e->src, bb_ld); bool dom_st = dominated_by_p (CDI_DOMINATORS, e->src, bb_st); if (dom_ld != dom_st) @@ -1611,7 +1615,7 @@ classify_partition (loop_p loop, struct graph *rdg, partition *partition, return; /* Find single load/store data references for builtin partition. */ - if (!find_single_drs (rdg, partition, &single_st, &single_ld)) + if (!find_single_drs (loop, rdg, partition, &single_st, &single_ld)) return; /* Classify the builtin kind. */ |