[gcc(refs/users/tnfchris/heads/gcc-14-early-break)] middle-end: Change loop analysis from looking at at number of BB to actual cfg

[gcc(refs/users/tnfchris/heads/gcc-14-early-break)] middle-end: Change loop analysis from looking at at number of BB to actual cfg

[Tamar Christina]

https://gcc.gnu.org/g:09acb16c3a7f2fc836f31d0c836128b785d6e939

commit 09acb16c3a7f2fc836f31d0c836128b785d6e939
Author: Tamar Christina <tamar.christina@arm.com>
Date:   Thu Nov 2 17:06:29 2023 +0000

    middle-end: Change loop analysis from looking at at number of BB to actual cfg
    
    Reviewed at https://reviewboard.gnu.aws.arm.com/r/17974/

Diff:
---
 gcc/tree-vect-loop-manip.cc |  2 --
 gcc/tree-vect-loop.cc       | 24 +++++++++++-------------
 2 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
index d00765c39bd..2c4566963ad 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -1886,12 +1886,10 @@ slpeel_can_duplicate_loop_p (const class loop *loop, const_edge exit_e,
   edge entry_e = loop_preheader_edge (loop);
   gcond *orig_cond = get_loop_exit_condition (exit_e);
   gimple_stmt_iterator loop_exit_gsi = gsi_last_bb (exit_e->src);
-  unsigned int num_bb = loop->inner? 5 : 2;
 
   /* All loops have an outer scope; the only case loop->outer is NULL is for
      the function itself.  */
   if (!loop_outer (loop)
-      || loop->num_nodes != num_bb
       || !empty_block_p (loop->latch)
       || !exit_e
       /* Verify that new loop exit condition can be trivially modified.  */
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index cd83cc0a67a..efea49a9237 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -1727,6 +1727,17 @@ vect_analyze_loop_form (class loop *loop, vect_loop_form_info *info)
 		       "using as main loop exit: %d -> %d [AUX: %p]\n",
 		       exit_e->src->index, exit_e->dest->index, exit_e->aux);
 
+  /* Check if we have any control flow that doesn't leave the loop.  */
+  class loop *v_loop = loop->inner ? loop->inner : loop;
+  basic_block *bbs= get_loop_body (v_loop);
+  for (unsigned i = 0; i < v_loop->num_nodes; i++)
+    if (EDGE_COUNT (bbs[i]->succs) != 1
+	&& (EDGE_COUNT (bbs[i]->succs) != 2
+	    || !loop_exits_from_bb_p (bbs[i]->loop_father, bbs[i])))
+      return opt_result::failure_at (vect_location,
+				     "not vectorized:"
+				     " unsupported control flow in loop.\n");
+
   /* Different restrictions apply when we are considering an inner-most loop,
      vs. an outer (nested) loop.
      (FORNOW. May want to relax some of these restrictions in the future).  */
@@ -1746,11 +1757,6 @@ vect_analyze_loop_form (class loop *loop, vect_loop_form_info *info)
                            |
                         (exit-bb)  */
 
-      if (loop->num_nodes != 2)
-	return opt_result::failure_at (vect_location,
-				       "not vectorized:"
-				       " control flow in loop.\n");
-
       if (empty_block_p (loop->header))
 	return opt_result::failure_at (vect_location,
 				       "not vectorized: empty loop.\n");
@@ -1782,11 +1788,6 @@ vect_analyze_loop_form (class loop *loop, vect_loop_form_info *info)
 				       "not vectorized:"
 				       " multiple nested loops.\n");
 
-      if (loop->num_nodes != 5)
-	return opt_result::failure_at (vect_location,
-				       "not vectorized:"
-				       " control flow in loop.\n");
-
       entryedge = loop_preheader_edge (innerloop);
       if (entryedge->src != loop->header
 	  || !single_exit (innerloop)
@@ -1823,9 +1824,6 @@ vect_analyze_loop_form (class loop *loop, vect_loop_form_info *info)
       info->inner_loop_cond = inner.conds[0];
     }
 
-  if (!single_exit (loop))
-    return opt_result::failure_at (vect_location,
-				   "not vectorized: multiple exits.\n");
   if (EDGE_COUNT (loop->header->preds) != 2)
     return opt_result::failure_at (vect_location,
 				   "not vectorized:"