[vect] Re-analyze all modes for epilogues

gcc/ChangeLog:

	* tree-vectorizer.c (better_epilogue_loop_than_p): Round factors up for
	epilogue costing.
	* tree-vect-loop.c (vect_analyze_loop): Re-analyze all modes for
	epilogues, unless we are guaranteed that we can't have partial vectors.
	* genopinit.c: (partial_vectors_supported): Generate new function.

gcc/testsuite/ChangeLog:

	* gcc.target/aarch64/masked_epilogue.c: New test.

1 files changed, 28 insertions, 0 deletions

diff --git a/gcc/genopinit.c b/gcc/genopinit.c
index c5cda28..fe0791c 100644
--- a/gcc/genopinit.c
+++ b/gcc/genopinit.c
@@ -320,6 +320,7 @@ main (int argc, const char **argv)
 	   "  signed char supports_vec_scatter_store[NUM_MACHINE_MODES];\n"
 	   "};\n"
 	   "extern void init_all_optabs (struct target_optabs *);\n"
+	   "extern bool partial_vectors_supported_p (void);\n"
 	   "\n"
 	   "extern struct target_optabs default_target_optabs;\n"
 	   "extern struct target_optabs *this_fn_optabs;\n"
@@ -372,6 +373,33 @@ main (int argc, const char **argv)
     fprintf (s_file, "  ena[%u] = HAVE_%s;\n", i, p->name);
   fprintf (s_file, "}\n\n");
 
+  fprintf (s_file,
+	   "/* Returns TRUE if the target supports any of the partial vector\n"
+	   "   optabs: while_ult_optab, len_load_optab or len_store_optab,\n"
+	   "   for any mode.  */\n"
+	   "bool\npartial_vectors_supported_p (void)\n{\n");
+  bool any_match = false;
+  fprintf (s_file, "\treturn");
+  bool first = true;
+  for (i = 0; patterns.iterate (i, &p); ++i)
+    {
+#define CMP_NAME(N) !strncmp (p->name, (N), strlen ((N)))
+      if (CMP_NAME("while_ult") || CMP_NAME ("len_load")
+	  || CMP_NAME ("len_store"))
+	{
+	  if (first)
+	    fprintf (s_file, " HAVE_%s", p->name);
+	  else
+	    fprintf (s_file, " || HAVE_%s", p->name);
+	  first = false;
+	  any_match = true;
+	}
+    }
+  if (!any_match)
+    fprintf (s_file, " false");
+  fprintf (s_file, ";\n}\n");
+
+
   /* Perform a binary search on a pre-encoded optab+mode*2.  */
   /* ??? Perhaps even better to generate a minimal perfect hash.
      Using gperf directly is awkward since it's so geared to working