re PR tree-optimization/56764 (vect_prune_runtime_alias_test_list not smart enough)

re PR tree-optimization/56764 (vect_prune_runtime_alias_test_list not smart enough)

2013-11-07  Cong Hou  <congh@google.com>

	PR tree-optimization/56764
	* tree-vect-loop-manip.c (vect_create_cond_for_alias_checks):
  	Combine alias checks if it is possible to amortize the runtime
  	overhead.  Return the number of alias checks after merging.
  	* tree-vect-data-refs.c (vect_prune_runtime_alias_test_list):
    	Use the function vect_create_cond_for_alias_checks () to check
    	the number of alias checks.

2013-11-07  Cong Hou  <congh@google.com>

    	* gcc.dg/vect/vect-alias-check.c: New.

From-SVN: r204538