[PATCH v2 11/14] vect: Disable use of partial vectors for uncounted loops

[Victor Do Nascimento]

Given the current reliance of masking on niters and the fact this is
undetermined for uncounted loops, we circumvent this limitation by
disabling the use of partial vectors when vectorizing loops with an
unkown upper bound.

gcc/ChangeLog:

        * tree-vect-loop.cc (vect_analyze_loop_2): Disable partial
        vector use for uncounted loops.
---
 gcc/tree-vect-loop.cc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 5f354e86a36..1cf4a11d0c8 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -2150,6 +2150,10 @@ vect_analyze_loop_2 (loop_vec_info loop_vinfo, int 
masked_p, bool &fatal,
     orig_loop_vinfo = loop_vinfo;
   gcc_assert (orig_loop_vinfo);
 
+  /* We can't mask on niters for uncounted loops due to unkown upper bound.  */
+  if (LOOP_VINFO_NITERS_UNCOUNTED_P (loop_vinfo))
+    LOOP_VINFO_CAN_USE_PARTIAL_VECTORS_P (loop_vinfo) = false;
+
   /* The first group of checks is independent of the vector size.  */
   fatal = true;
 
-- 
2.43.0