[PATCH] Generic vector op costing adjustment

[PATCH] Generic vector op costing adjustment

[Richard Biener]

This is a small adjustment to the work done for PR108752 and
better reflects the cost of the generated sequence.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

	PR tree-optimization/108752
	* tree-vect-stmts.cc (vectorizable_operation): For bit
	operations with generic word_mode vectors do not cost
	an extra stmt.  For plus, minus and negate also cost the
	constant materialization.
---
 gcc/tree-vect-stmts.cc | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 0022b878767..127b987cd62 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -6466,8 +6466,8 @@ vectorizable_operation (vec_info *vinfo,
 	{
 	  /* The above vect_model_simple_cost call handles constants
 	     in the prologue and (mis-)costs one of the stmts as
-	     vector stmt.  See tree-vect-generic.cc:do_plus_minus/do_negate
-	     for the actual lowering that will be applied.  */
+	     vector stmt.  See below for the actual lowering that will
+	     be applied.  */
 	  unsigned n
 	    = slp_node ? SLP_TREE_NUMBER_OF_VEC_STMTS (slp_node) : ncopies;
 	  switch (code)
@@ -6481,9 +6481,20 @@ vectorizable_operation (vec_info *vinfo,
 	    case NEGATE_EXPR:
 	      n *= 4;
 	      break;
-	    default:;
+	    default:
+	      /* Bit operations do not have extra cost and are accounted
+		 as vector stmt by vect_model_simple_cost.  */
+	      n = 0;
+	      break;
+	    }
+	  if (n != 0)
+	    {
+	      /* We also need to materialize two large constants.  */
+	      record_stmt_cost (cost_vec, 2, scalar_stmt, stmt_info,
+				0, vect_prologue);
+	      record_stmt_cost (cost_vec, n, scalar_stmt, stmt_info,
+				0, vect_body);
 	    }
-	  record_stmt_cost (cost_vec, n, scalar_stmt, stmt_info, 0, vect_body);
 	}
       return true;
     }
-- 
2.35.3