Disable --param vect-partial-vector-usage by default on x86

The following defaults --param vect-partial-vector-usage to zero
for x86_64 matching existing behavior where support for this
is not present.

2021-07-15  Richard Biener  <rguenther@suse.de>

	* config/i386/i386-options.c (ix86_option_override_internal): Set
	param_vect_partial_vector_usage to zero if not set.

diff --git a/gcc/config/i386/i386-options.c b/gcc/config/i386/i386-options.c
index 7cba655..3416a4f 100644 (file)
--- a/gcc/config/i386/i386-options.c
+++ b/gcc/config/i386/i386-options.c
@@ -2834,6 +2834,11 @@ ix86_option_override_internal (bool main_args_p,
 
   SET_OPTION_IF_UNSET (opts, opts_set, param_ira_consider_dup_in_all_alts, 0);
 
+  /* Fully masking the main or the epilogue vectorized loop is not
+     profitable generally so leave it disabled until we get more
+     fine grained control & costing.  */
+  SET_OPTION_IF_UNSET (opts, opts_set, param_vect_partial_vector_usage, 0);
+
   return true;
 }