diff options
Diffstat (limited to 'gcc/tree-vect-data-refs.c')
| -rw-r--r-- | gcc/tree-vect-data-refs.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c index e973b34..fbc35a3 100644 --- a/gcc/tree-vect-data-refs.c +++ b/gcc/tree-vect-data-refs.c @@ -403,6 +403,13 @@ vect_analyze_data_ref_dependence (struct data_dependence_relation *ddr, if (dump_enabled_p ()) dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, "dependence distance negative.\n"); + /* 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. */ + if (DR_IS_READ (drb) + && (STMT_VINFO_MIN_NEG_DIST (stmtinfo_b) == 0 + || STMT_VINFO_MIN_NEG_DIST (stmtinfo_b) > (unsigned)dist)) + STMT_VINFO_MIN_NEG_DIST (stmtinfo_b) = dist; continue; } |