re PR debug/46799 (-fcompare-debug failure (length) with -ftree-parallelize-loops...

re PR debug/46799 (-fcompare-debug failure (length) with -ftree-parallelize-loops=2 -fno-tree-dce)

	PR debug/46799
	* tree-parloops.c (separate_decls_in_region): Use UNKNOWN_LOCATION
	instead of BUILTINS_LOCATION.
	(create_loop_fn): Add LOC argument, pass it to build_decl instead of
	BUILTINS_LOCATION.
	(create_parallel_loop): Add LOC argument, use it for OMP clauses
	and GIMPLE_*OMP* statements.
	(gen_parallel_loop): Determine locus for the parallel loop, pass it
	to create_loop_fn and create_parallel_loop.
	* cfgexpand.c (gimple_expand_cfg): For builtin functions, call
	set_curr_insn_source_location (UNKNOWN_LOCATION).

	* gcc.dg/autopar/pr46799.c: New test.

From-SVN: r167533