re PR tree-optimization/46590 (long compile time with -O2 and many loops)

re PR tree-optimization/46590 (long compile time with -O2 and many loops)

2014-01-17  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/46590
	* vec.h (vec<>::bseach): New member function implementing
	binary search according to C89 bsearch.
	(vec<>::qsort): Avoid calling ::qsort for vectors with sizes 0 or 1.
	* tree-ssa-loop-im.c (struct mem_ref): Make stored member a
	bitmap pointer again.  Make accesses_in_loop a flat array.
	(mem_ref_obstack): New global.
	(outermost_indep_loop): Adjust for mem_ref->stored changes.
	(mark_ref_stored): Likewise.
	(ref_indep_loop_p_2): Likewise.
	(set_ref_stored_in_loop): New helper function.
	(mem_ref_alloc): Allocate mem_refs on the mem_ref_obstack obstack.
	(memref_free): Adjust.
	(record_mem_ref_loc): Simplify.
	(gather_mem_refs_stmt): Adjust.
	(sort_locs_in_loop_postorder_cmp): New function.
	(analyze_memory_references): Sort accesses_in_loop after
	loop postorder number.
	(find_ref_loc_in_loop_cmp): New function.
	(for_all_locs_in_loop): Find relevant cluster of locs in
	accesses_in_loop and iterate without recursion.
	(execute_sm): Avoid uninit warning.
	(struct ref_always_accessed): Simplify.
	(ref_always_accessed::operator ()): Likewise.
	(ref_always_accessed_p): Likewise.
	(tree_ssa_lim_initialize): Initialize mem_ref_obstack, compute
	loop postorder numbers here.
	(tree_ssa_lim_finalize): Free mem_ref_obstack and loop postorder
	numbers.

From-SVN: r206709