PR tree-optimization/30858

        * tree-vectorizer.c (vect_is_simple_reduction): Check that the stmts
        in the reduction cycle have a single use in the loop.
        * tree-vectorizer.h (relevant): Add documentation.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@122220 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 44 insertions, 8 deletions

diff --git a/gcc/tree-vectorizer.c b/gcc/tree-vectorizer.c
index fab57234ed9..2a53b9c9fa3 100644
--- a/gcc/tree-vectorizer.c
+++ b/gcc/tree-vectorizer.c
@@ -1935,14 +1935,35 @@ vect_is_simple_reduction (struct loop *loop, tree phi)
   int op_type;
   tree operation, op1, op2;
   tree type;
+  int nloop_uses;
+  tree name;
+  imm_use_iterator imm_iter;
+  use_operand_p use_p;
 
-  if (TREE_CODE (loop_arg) != SSA_NAME)
+  name = PHI_RESULT (phi);
+  nloop_uses = 0;
+  FOR_EACH_IMM_USE_FAST (use_p, imm_iter, name)
     {
-      if (vect_print_dump_info (REPORT_DETAILS))
+      tree use_stmt = USE_STMT (use_p);
+      if (flow_bb_inside_loop_p (loop, bb_for_stmt (use_stmt))
+	  && vinfo_for_stmt (use_stmt)
+	  && !is_pattern_stmt_p (vinfo_for_stmt (use_stmt)))
+        nloop_uses++;
+      if (nloop_uses > 1)
         {
-          fprintf (vect_dump, "reduction: not ssa_name: ");
-          print_generic_expr (vect_dump, loop_arg, TDF_SLIM);
+          if (vect_print_dump_info (REPORT_DETAILS))
+            fprintf (vect_dump, "reduction used in loop.");
+          return NULL_TREE;
         }
+    }
+
+  if (TREE_CODE (loop_arg) != SSA_NAME)
+    {
+      if (vect_print_dump_info (REPORT_DETAILS))
+	{
+	  fprintf (vect_dump, "reduction: not ssa_name: ");
+	  print_generic_expr (vect_dump, loop_arg, TDF_SLIM);
+	}
       return NULL_TREE;
     }
 
@@ -1950,19 +1971,34 @@ vect_is_simple_reduction (struct loop *loop, tree phi)
   if (!def_stmt)
     {
       if (vect_print_dump_info (REPORT_DETAILS))
-        fprintf (vect_dump, "reduction: no def_stmt.");
+	fprintf (vect_dump, "reduction: no def_stmt.");
       return NULL_TREE;
     }
 
   if (TREE_CODE (def_stmt) != GIMPLE_MODIFY_STMT)
     {
       if (vect_print_dump_info (REPORT_DETAILS))
-        {
-          print_generic_expr (vect_dump, def_stmt, TDF_SLIM);
-        }
+        print_generic_expr (vect_dump, def_stmt, TDF_SLIM);
       return NULL_TREE;
     }
 
+  name = GIMPLE_STMT_OPERAND (def_stmt, 0);
+  nloop_uses = 0;
+  FOR_EACH_IMM_USE_FAST (use_p, imm_iter, name)
+    {
+      tree use_stmt = USE_STMT (use_p);
+      if (flow_bb_inside_loop_p (loop, bb_for_stmt (use_stmt))
+	  && vinfo_for_stmt (use_stmt)
+	  && !is_pattern_stmt_p (vinfo_for_stmt (use_stmt)))
+	nloop_uses++;
+      if (nloop_uses > 1)
+	{
+	  if (vect_print_dump_info (REPORT_DETAILS))
+	    fprintf (vect_dump, "reduction used in loop.");
+	  return NULL_TREE;
+	}
+    }
+
   operation = GIMPLE_STMT_OPERAND (def_stmt, 1);
   code = TREE_CODE (operation);
   if (!commutative_tree_code (code) || !associative_tree_code (code))