[gcc r12-8133] Revert "tree-optimization/104912 - ensure cost model is checked first"

[gcc r12-8133] Revert "tree-optimization/104912 - ensure cost model is checked first"

[Richard Biener]

https://gcc.gnu.org/g:6e609e0010c76d708097cbcf1c67fded6010a0e0

commit r12-8133-g6e609e0010c76d708097cbcf1c67fded6010a0e0
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Apr 13 09:54:58 2022 +0200

    Revert "tree-optimization/104912 - ensure cost model is checked first"
    
    This reverts commit ac8340ee4d1e65f3fd41c547b16895875f4aefa7.

Diff:
---
 gcc/tree-vect-loop-manip.cc | 60 +++------------------------------------------
 1 file changed, 3 insertions(+), 57 deletions(-)

diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
index e4381eb7079..63fb6f669a0 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -3445,34 +3445,13 @@ vect_loop_versioning (loop_vec_info loop_vinfo,
 	cond_expr = expr;
     }
 
-  tree cost_name = NULL_TREE;
-  profile_probability prob2 = profile_probability::uninitialized ();
-  if (cond_expr
-      && !integer_truep (cond_expr)
-      && (version_niter
-	  || version_align
-	  || version_alias
-	  || version_simd_if_cond))
-    {
-      cost_name = cond_expr = force_gimple_operand_1 (unshare_expr (cond_expr),
-						      &cond_expr_stmt_list,
-						      is_gimple_val, NULL_TREE);
-      /* Split prob () into two so that the overall probability of passing
-	 both the cost-model and versioning checks is the orig prob.  */
-      prob2 = prob.split (prob);
-    }
-
   if (version_niter)
     vect_create_cond_for_niters_checks (loop_vinfo, &cond_expr);
 
   if (cond_expr)
-    {
-      gimple_seq tem = NULL;
-      cond_expr = force_gimple_operand_1 (unshare_expr (cond_expr),
-					  &tem,
-					  is_gimple_condexpr, NULL_TREE);
-      gimple_seq_add_seq (&cond_expr_stmt_list, tem);
-    }
+    cond_expr = force_gimple_operand_1 (unshare_expr (cond_expr),
+					&cond_expr_stmt_list,
+					is_gimple_condexpr, NULL_TREE);
 
   if (version_align)
     vect_create_cond_for_align_checks (loop_vinfo, &cond_expr,
@@ -3676,39 +3655,6 @@ vect_loop_versioning (loop_vec_info loop_vinfo,
       update_ssa (TODO_update_ssa);
     }
 
-  /* Split the cost model check off to a separate BB.  Costing assumes
-     this is the only thing we perform when we enter the scalar loop
-     from a failed cost decision.  */
-  if (cost_name && TREE_CODE (cost_name) == SSA_NAME)
-    {
-      gimple *def = SSA_NAME_DEF_STMT (cost_name);
-      /* All uses of the cost check are 'true' after the check we
-	 are going to insert.  */
-      replace_uses_by (cost_name, boolean_true_node);
-      /* And we're going to build the new single use of it.  */
-      gcond *cond = gimple_build_cond (NE_EXPR, cost_name, boolean_false_node,
-				       NULL_TREE, NULL_TREE);
-      edge e = split_block (gimple_bb (def), def);
-      gimple_stmt_iterator gsi = gsi_for_stmt (def);
-      gsi_insert_after (&gsi, cond, GSI_NEW_STMT);
-      edge true_e, false_e;
-      extract_true_false_edges_from_block (e->dest, &true_e, &false_e);
-      e->flags &= ~EDGE_FALLTHRU;
-      e->flags |= EDGE_TRUE_VALUE;
-      edge e2 = make_edge (e->src, false_e->dest, EDGE_FALSE_VALUE);
-      e->probability = prob2;
-      e2->probability = prob2.invert ();
-      set_immediate_dominator (CDI_DOMINATORS, false_e->dest, e->src);
-      auto_vec<basic_block, 3> adj;
-      for (basic_block son = first_dom_son (CDI_DOMINATORS, e->dest);
-	   son;
-	   son = next_dom_son (CDI_DOMINATORS, son))
-	if (EDGE_COUNT (son->preds) > 1)
-	  adj.safe_push (son);
-      for (auto son : adj)
-	set_immediate_dominator (CDI_DOMINATORS, son, e->src);
-    }
-
   if (version_niter)
     {
       /* The versioned loop could be infinite, we need to clear existing