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authorAndre Vieira <andre.simoesdiasvieira@arm.com>2021-06-03 13:55:24 +0100
committerAndre Vieira <andre.simoesdiasvieira@arm.com>2021-06-03 13:55:24 +0100
commit7ed1cd9665d8ca0fa07b2483e604c25e704584af (patch)
tree55c9ffd6adcd0b3464eeef16875b0e535b86bd08 /gcc/tree-vect-loop.c
parentf4242710c7966a965bbd14cd50ecdba28fd5717e (diff)
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vect: Use main loop's thresholds and VF to narrow upper_bound of epilogue
This patch uses the knowledge of the conditions to enter an epilogue loop to help come up with a potentially more restricive upper bound. gcc/ChangeLog: * tree-vect-loop.c (vect_transform_loop): Use main loop's various' thresholds to narrow the upper bound on epilogue iterations. gcc/testsuite/ChangeLog: * gcc.target/aarch64/sve/part_vect_single_iter_epilog.c: New test.
Diffstat (limited to 'gcc/tree-vect-loop.c')
-rw-r--r--gcc/tree-vect-loop.c31
1 files changed, 25 insertions, 6 deletions
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index ff7673d..ba36348 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -9740,12 +9740,31 @@ vect_transform_loop (loop_vec_info loop_vinfo, gimple *loop_vectorized_call)
/* In these calculations the "- 1" converts loop iteration counts
back to latch counts. */
if (loop->any_upper_bound)
- loop->nb_iterations_upper_bound
- = (final_iter_may_be_partial
- ? wi::udiv_ceil (loop->nb_iterations_upper_bound + bias_for_lowest,
- lowest_vf) - 1
- : wi::udiv_floor (loop->nb_iterations_upper_bound + bias_for_lowest,
- lowest_vf) - 1);
+ {
+ loop_vec_info main_vinfo = LOOP_VINFO_ORIG_LOOP_INFO (loop_vinfo);
+ loop->nb_iterations_upper_bound
+ = (final_iter_may_be_partial
+ ? wi::udiv_ceil (loop->nb_iterations_upper_bound + bias_for_lowest,
+ lowest_vf) - 1
+ : wi::udiv_floor (loop->nb_iterations_upper_bound + bias_for_lowest,
+ lowest_vf) - 1);
+ if (main_vinfo)
+ {
+ unsigned int bound;
+ poly_uint64 main_iters
+ = upper_bound (LOOP_VINFO_VECT_FACTOR (main_vinfo),
+ LOOP_VINFO_COST_MODEL_THRESHOLD (main_vinfo));
+ main_iters
+ = upper_bound (main_iters,
+ LOOP_VINFO_VERSIONING_THRESHOLD (main_vinfo));
+ if (can_div_away_from_zero_p (main_iters,
+ LOOP_VINFO_VECT_FACTOR (loop_vinfo),
+ &bound))
+ loop->nb_iterations_upper_bound
+ = wi::umin ((widest_int) (bound - 1),
+ loop->nb_iterations_upper_bound);
+ }
+ }
if (loop->any_likely_upper_bound)
loop->nb_iterations_likely_upper_bound
= (final_iter_may_be_partial