[Bug tree-optimization/84777] -Os inhibits all vectorization

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84777

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu.org

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
IIRC the issue is that -Os inhibits most loop-header copying.

Can you provide a testcase that shows the issue please?

Can you check if the following patch fixes things for you?

Index: gcc/tree-ssa-loop-ch.c
===================================================================
--- gcc/tree-ssa-loop-ch.c      (revision 258380)
+++ gcc/tree-ssa-loop-ch.c      (working copy)
@@ -257,8 +257,7 @@ public:
   /* opt_pass methods: */
   virtual bool gate (function *fun)
   {
-    return flag_tree_ch != 0
-          && (flag_tree_loop_vectorize != 0 ||
fun->has_force_vectorize_loops);
+    return flag_tree_loop_vectorize != 0 || fun->has_force_vectorize_loops;
   }

   /* Just copy headers, no initialization/finalization of loop structures.  */