[gcc r15-1461] vect: Add a function to check lane-reducing stmt

[Feng Xue]

https://gcc.gnu.org/g:70466e6f9d9fb87f78ffe2e397ca876b380cb493

commit r15-1461-g70466e6f9d9fb87f78ffe2e397ca876b380cb493
Author: Feng Xue <fxue@os.amperecomputing.com>
Date:   Sat Jun 15 23:17:10 2024 +0800

    vect: Add a function to check lane-reducing stmt
    
    Add a utility function to check if a statement is lane-reducing operation,
    which could simplify some existing code.
    
    2024-06-16 Feng Xue <fxue@os.amperecomputing.com>
    
    gcc/
            * tree-vectorizer.h (lane_reducing_stmt_p): New function.
            * tree-vect-slp.cc (vect_analyze_slp): Use new function
            lane_reducing_stmt_p to check statement.

Diff:
---
 gcc/tree-vect-slp.cc  |  4 +---
 gcc/tree-vectorizer.h | 12 ++++++++++++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 7d18b5bfee5d..a5665946a4eb 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -3919,7 +3919,6 @@ vect_analyze_slp (vec_info *vinfo, unsigned max_tree_size)
 	  scalar_stmts.create (loop_vinfo->reductions.length ());
 	  for (auto next_info : loop_vinfo->reductions)
 	    {
-	      gassign *g;
 	      next_info = vect_stmt_to_vectorize (next_info);
 	      if ((STMT_VINFO_RELEVANT_P (next_info)
 		   || STMT_VINFO_LIVE_P (next_info))
@@ -3931,8 +3930,7 @@ vect_analyze_slp (vec_info *vinfo, unsigned max_tree_size)
 		{
 		  /* Do not discover SLP reductions combining lane-reducing
 		     ops, that will fail later.  */
-		  if (!(g = dyn_cast <gassign *> (STMT_VINFO_STMT (next_info)))
-		      || !lane_reducing_op_p (gimple_assign_rhs_code (g)))
+		  if (!lane_reducing_stmt_p (STMT_VINFO_STMT (next_info)))
 		    scalar_stmts.quick_push (next_info);
 		  else
 		    {
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index 6bb0f5c3a56f..60224f4e2847 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -2169,12 +2169,24 @@ vect_apply_runtime_profitability_check_p (loop_vec_info loop_vinfo)
 	  && th >= vect_vf_for_cost (loop_vinfo));
 }
 
+/* Return true if CODE is a lane-reducing opcode.  */
+
 inline bool
 lane_reducing_op_p (code_helper code)
 {
   return code == DOT_PROD_EXPR || code == WIDEN_SUM_EXPR || code == SAD_EXPR;
 }
 
+/* Return true if STMT is a lane-reducing statement.  */
+
+inline bool
+lane_reducing_stmt_p (gimple *stmt)
+{
+  if (auto *assign = dyn_cast <gassign *> (stmt))
+    return lane_reducing_op_p (gimple_assign_rhs_code (assign));
+  return false;
+}
+
 /* Source location + hotness information. */
 extern dump_user_location_t vect_location;