diff options
Diffstat (limited to 'gcc/tree-vect-loop.c')
| -rw-r--r-- | gcc/tree-vect-loop.c | 38 |
1 files changed, 36 insertions, 2 deletions
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c index 0470445..9cca9b7 100644 --- a/gcc/tree-vect-loop.c +++ b/gcc/tree-vect-loop.c @@ -6620,6 +6620,39 @@ vect_loop_kill_debug_uses (struct loop *loop, gimple *stmt) } } +/* Given loop represented by LOOP_VINFO, return true if computation of + LOOP_VINFO_NITERS (= LOOP_VINFO_NITERSM1 + 1) doesn't overflow, false + otherwise. */ + +static bool +loop_niters_no_overflow (loop_vec_info loop_vinfo) +{ + /* Constant case. */ + if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)) + { + tree cst_niters = LOOP_VINFO_NITERS (loop_vinfo); + tree cst_nitersm1 = LOOP_VINFO_NITERSM1 (loop_vinfo); + + gcc_assert (TREE_CODE (cst_niters) == INTEGER_CST); + gcc_assert (TREE_CODE (cst_nitersm1) == INTEGER_CST); + if (wi::to_widest (cst_nitersm1) < wi::to_widest (cst_niters)) + return true; + } + + widest_int max; + struct loop *loop = LOOP_VINFO_LOOP (loop_vinfo); + /* Check the upper bound of loop niters. */ + if (get_max_loop_iterations (loop, &max)) + { + tree type = TREE_TYPE (LOOP_VINFO_NITERS (loop_vinfo)); + signop sgn = TYPE_SIGN (type); + widest_int type_max = widest_int::from (wi::max_value (type), sgn); + if (max < type_max) + return true; + } + return false; +} + /* Function vect_transform_loop. The analysis phase has determined that the loop is vectorizable. @@ -6707,8 +6740,9 @@ vect_transform_loop (loop_vec_info loop_vinfo) tree niters = vect_build_loop_niters (loop_vinfo); LOOP_VINFO_NITERS_UNCHANGED (loop_vinfo) = niters; tree nitersm1 = unshare_expr (LOOP_VINFO_NITERSM1 (loop_vinfo)); + bool niters_no_overflow = loop_niters_no_overflow (loop_vinfo); vect_do_peeling (loop_vinfo, niters, nitersm1, &niters_vector, th, - check_profitability, false); + check_profitability, niters_no_overflow); if (niters_vector == NULL_TREE) { if (LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)) @@ -6717,7 +6751,7 @@ vect_transform_loop (loop_vec_info loop_vinfo) LOOP_VINFO_INT_NITERS (loop_vinfo) / vf); else vect_gen_vector_loop_niters (loop_vinfo, niters, &niters_vector, - false); + niters_no_overflow); } /* 1) Make sure the loop header has exactly two entries |