tree-optimization/103102 - fix error in vectorizer refactoring

This fixes an oversight that caused vectorized epilogues to have
versioning for niters applied.

2021-11-08  Richard Biener  <rguenther@suse.de>

	* tree-vectorizer.h (vect_create_loop_vinfo): Add main_loop_info
	parameter.
	* tree-vect-loop.c (vect_create_loop_vinfo): Likewise.  Set
	LOOP_VINFO_ORIG_LOOP_INFO and conditionalize set of
	LOOP_VINFO_NITERS_ASSUMPTIONS.
	(vect_analyze_loop_1): Adjust.
	(vect_analyze_loop): Move loop constraint setting and
	SCEV/niter reset here from vect_create_loop_vinfo to perform
	it only once.
	(vect_analyze_loop_form): Move dumping of symbolic niters
	here from vect_create_loop_vinfo.

diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index b56b7a4a38640e477e13c8a1a80d5b3318f7da3a..ede9aff0522c17bc71f971f6d8bd4aaab2983685 100644 (file)
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -1464,6 +1464,18 @@ vect_analyze_loop_form (class loop *loop, vect_loop_form_info *info)
       (info->loop_cond,
        "not vectorized: number of iterations = 0.\n");
 
+  if (!(tree_fits_shwi_p (info->number_of_iterations)
+       && tree_to_shwi (info->number_of_iterations) > 0))
+    {
+      if (dump_enabled_p ())
+       {
+         dump_printf_loc (MSG_NOTE, vect_location,
+                          "Symbolic number of iterations is ");
+         dump_generic_expr (MSG_NOTE, TDF_DETAILS, info->number_of_iterations);
+         dump_printf (MSG_NOTE, "\n");
+       }
+    }
+
   return opt_result::success ();
 }
 
@@ -1472,36 +1484,17 @@ vect_analyze_loop_form (class loop *loop, vect_loop_form_info *info)
 
 loop_vec_info
 vect_create_loop_vinfo (class loop *loop, vec_info_shared *shared,
-                       const vect_loop_form_info *info)
+                       const vect_loop_form_info *info,
+                       loop_vec_info main_loop_info)
 {
   loop_vec_info loop_vinfo = new _loop_vec_info (loop, shared);
   LOOP_VINFO_NITERSM1 (loop_vinfo) = info->number_of_iterationsm1;
   LOOP_VINFO_NITERS (loop_vinfo) = info->number_of_iterations;
   LOOP_VINFO_NITERS_UNCHANGED (loop_vinfo) = info->number_of_iterations;
-  if (!integer_onep (info->assumptions))
-    {
-      /* We consider to vectorize this loop by versioning it under
-        some assumptions.  In order to do this, we need to clear
-        existing information computed by scev and niter analyzer.  */
-      scev_reset_htab ();
-      free_numbers_of_iterations_estimates (loop);
-      /* Also set flag for this loop so that following scev and niter
-        analysis are done under the assumptions.  */
-      loop_constraint_set (loop, LOOP_C_FINITE);
-      /* Also record the assumptions for versioning.  */
-      LOOP_VINFO_NITERS_ASSUMPTIONS (loop_vinfo) = info->assumptions;
-    }
-
-  if (!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo))
-    {
-      if (dump_enabled_p ())
-        {
-          dump_printf_loc (MSG_NOTE, vect_location,
-                          "Symbolic number of iterations is ");
-         dump_generic_expr (MSG_NOTE, TDF_DETAILS, info->number_of_iterations);
-          dump_printf (MSG_NOTE, "\n");
-        }
-    }
+  LOOP_VINFO_ORIG_LOOP_INFO (loop_vinfo) = main_loop_info;
+  /* Also record the assumptions for versioning.  */
+  if (!integer_onep (info->assumptions) && !main_loop_info)
+    LOOP_VINFO_NITERS_ASSUMPTIONS (loop_vinfo) = info->assumptions;
 
   stmt_vec_info loop_cond_info = loop_vinfo->lookup_stmt (info->loop_cond);
   STMT_VINFO_TYPE (loop_cond_info) = loop_exit_ctrl_vec_info_type;
@@ -2903,9 +2896,7 @@ vect_analyze_loop_1 (class loop *loop, vec_info_shared *shared,
                     bool &fatal)
 {
   loop_vec_info loop_vinfo
-    = vect_create_loop_vinfo (loop, shared, loop_form_info);
-  if (main_loop_vinfo)
-    LOOP_VINFO_ORIG_LOOP_INFO (loop_vinfo) = main_loop_vinfo;
+    = vect_create_loop_vinfo (loop, shared, loop_form_info, main_loop_vinfo);
 
   machine_mode vector_mode = vector_modes[mode_i];
   loop_vinfo->vector_mode = vector_mode;
@@ -2997,6 +2988,17 @@ vect_analyze_loop (class loop *loop, vec_info_shared *shared)
                         "bad loop form.\n");
       return opt_loop_vec_info::propagate_failure (res);
     }
+  if (!integer_onep (loop_form_info.assumptions))
+    {
+      /* We consider to vectorize this loop by versioning it under
+        some assumptions.  In order to do this, we need to clear
+        existing information computed by scev and niter analyzer.  */
+      scev_reset_htab ();
+      free_numbers_of_iterations_estimates (loop);
+      /* Also set flag for this loop so that following scev and niter
+        analysis are done under the assumptions.  */
+      loop_constraint_set (loop, LOOP_C_FINITE);
+    }
 
   auto_vector_modes vector_modes;
   /* Autodetect first vector size we try.  */

diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index 7d3d3935c957fba972b13c428a446ff49b1508fa..b552e9dccce5bce6a3bbcf5d531e7ccefa719b9a 100644 (file)
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -2160,7 +2160,8 @@ struct vect_loop_form_info
 };
 extern opt_result vect_analyze_loop_form (class loop *, vect_loop_form_info *);
 extern loop_vec_info vect_create_loop_vinfo (class loop *, vec_info_shared *,
-                                            const vect_loop_form_info *);
+                                            const vect_loop_form_info *,
+                                            loop_vec_info = nullptr);
 extern bool vectorizable_live_operation (vec_info *,
                                         stmt_vec_info, gimple_stmt_iterator *,
                                         slp_tree, slp_instance, int,