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| author | Bin Cheng <bin.cheng@linux.alibaba.com> | 2019-03-26 11:12:37 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2019-03-26 11:12:37 +0000 |
| commit | f30d4934a90a6121674d882d391dc09d8fce190c (patch) | |
| tree | dceaf13c79931e68028dfe72926292485c514420 /gcc/tree-vect-data-refs.c | |
| parent | a235c72e64a2ec26d63d614e3d1ce12a7e061201 (diff) | |
| download | gcc-f30d4934a90a6121674d882d391dc09d8fce190c.zip gcc-f30d4934a90a6121674d882d391dc09d8fce190c.tar.gz gcc-f30d4934a90a6121674d882d391dc09d8fce190c.tar.bz2 | |
re PR tree-optimization/81740 (wrong code at -O3 in both 32-bit and 64-bit modes on x86_64-linux-gnu)
2019-03-26 Bin Cheng <bin.cheng@linux.alibaba.com>
PR tree-optimization/81740
* tree-vect-data-refs.c (vect_analyze_data_ref_dependence):
In case of outer loop vectorization, check for backward dependence
at the inner loop if outer loop dependence is reversed.
* gcc.dg/vect/pr81740-1.c: New testcase.
* gcc.dg/vect/pr81740-2.c: Likewise.
From-SVN: r269938
Diffstat (limited to 'gcc/tree-vect-data-refs.c')
| -rw-r--r-- | gcc/tree-vect-data-refs.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c index 7bbd47f..1380088 100644 --- a/gcc/tree-vect-data-refs.c +++ b/gcc/tree-vect-data-refs.c @@ -473,8 +473,22 @@ vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr, reversed (to make distance vector positive), and the actual distance is negative. */ if (dump_enabled_p ()) - dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, + dump_printf_loc (MSG_NOTE, vect_location, "dependence distance negative.\n"); + /* When doing outer loop vectorization, we need to check if there is + a backward dependence at the inner loop level if the dependence + at the outer loop is reversed. See PR81740. */ + if (nested_in_vect_loop_p (loop, stmtinfo_a) + || nested_in_vect_loop_p (loop, stmtinfo_b)) + { + unsigned inner_depth = index_in_loop_nest (loop->inner->num, + DDR_LOOP_NEST (ddr)); + if (dist_v[inner_depth] < 0) + return opt_result::failure_at (stmtinfo_a->stmt, + "not vectorized, dependence " + "between data-refs %T and %T\n", + DR_REF (dra), DR_REF (drb)); + } /* Record a negative dependence distance to later limit the amount of stmt copying / unrolling we can perform. Only need to handle read-after-write dependence. */ @@ -490,7 +504,7 @@ vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr, { /* The dependence distance requires reduction of the maximal vectorization factor. */ - *max_vf = abs (dist); + *max_vf = abs_dist; if (dump_enabled_p ()) dump_printf_loc (MSG_NOTE, vect_location, "adjusting maximal vectorization factor to %i\n", |