Fix vect_need_peeling_or_partial_vectors_p wrt peeling for gaps

The code assuming that peeling for gaps can be elided by means of
knowing niters and prologue peeling is wrong.  Peeling for gaps
means we need an epilog.

	* tree-vect-loop.cc (vect_need_peeling_or_partial_vectors_p):
	When peeling for gaps we always need an epilog.

diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 82121ca21ba4c27e1851e2f112bbd3a002fa36ed..53923c07e181cc330b8c4ac383cb02b3647d3963 100644 (file)
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -942,6 +942,9 @@ vect_need_peeling_or_partial_vectors_p (loop_vec_info loop_vinfo)
 {
   unsigned HOST_WIDE_INT const_vf;
 
+  if (LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo))
+    return true;
+
   loop_vec_info main_loop_vinfo
     = (LOOP_VINFO_EPILOGUE_P (loop_vinfo)
        ? LOOP_VINFO_MAIN_LOOP_INFO (loop_vinfo) : loop_vinfo);
@@ -952,14 +955,11 @@ vect_need_peeling_or_partial_vectors_p (loop_vec_info loop_vinfo)
         peeled for reasons other than niters.  */
       unsigned int peel_niter
        = LOOP_VINFO_PEELING_FOR_ALIGNMENT (main_loop_vinfo);
-      if (LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo))
-       peel_niter += 1;
       return !multiple_p (LOOP_VINFO_INT_NITERS (loop_vinfo) - peel_niter,
                          LOOP_VINFO_VECT_FACTOR (loop_vinfo));
     }
 
   if (!LOOP_VINFO_PEELING_FOR_ALIGNMENT (main_loop_vinfo)
-      && !LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo)
       && LOOP_VINFO_VECT_FACTOR (loop_vinfo).is_constant (&const_vf))
     {
       /* When the number of iterations is a multiple of the vectorization