The following restores the use of .SELECT_VL for testcases where it
is safe to use even when using SLP. I've for now restricted it
to single-lane SLP plus optimistically allow store-lane nodes
and assume single-lane roots are not widened but at most to
load-lane who should be fine.
Bootstrap and regtest running on x86_64-unknwon-linux-gnu.
PR tree-optimization/116573
* tree-vect-loop.cc (vect_analyze_loop_2): Allow .SELECV_VL
for SLP but disable it when there's multi-lane instances.
---
gcc/tree-vect-loop.cc | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 62c7f90779f..199d79029e4 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -3078,10 +3078,23 @@ start_over:
if (direct_internal_fn_supported_p (IFN_SELECT_VL, iv_type,
OPTIMIZE_FOR_SPEED)
&& LOOP_VINFO_LENS (loop_vinfo).length () == 1
- && LOOP_VINFO_LENS (loop_vinfo)[0].factor == 1 && !slp
+ && LOOP_VINFO_LENS (loop_vinfo)[0].factor == 1
&& (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
|| !LOOP_VINFO_VECT_FACTOR (loop_vinfo).is_constant ()))
LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo) = true;
+
+ /* If any of the SLP instances cover more than a single lane
+ we cannot use .SELECT_VL at the moment, even if the number
+ of lanes is uniform throughout the SLP graph. */
+ if (LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo))
+ for (slp_instance inst : LOOP_VINFO_SLP_INSTANCES (loop_vinfo))
+ if (SLP_TREE_LANES (SLP_INSTANCE_TREE (inst)) != 1
+ && !(SLP_INSTANCE_KIND (inst) == slp_inst_kind_store
+ && SLP_INSTANCE_TREE (inst)->ldst_lanes))
+ {
+ LOOP_VINFO_USING_SELECT_VL_P (loop_vinfo) = false;
+ break;
+ }
}
/* Decide whether this loop_vinfo should use partial vectors or peeling,
--
2.43.0
