diff mbox series

tree-optimization/116573 - .SELECT_VL for SLP

Message ID 20240917092436.C52B6139CE@imap1.dmz-prg2.suse.org
State New
Headers show
Series tree-optimization/116573 - .SELECT_VL for SLP | expand

Commit Message

Richard Biener Sept. 17, 2024, 9:24 a.m. UTC 
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 mbox series

Patch

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,