re PR middle-end/37275 (ICE when compile libgomp/task.c)

re PR middle-end/37275 (ICE when compile libgomp/task.c)

	PR middle-end/37275
	* dwarf2out.c (tls_mem_loc_descriptor): New function.
	(mem_loc_descriptor): Use it for MEM.  For PLUS fail if second
	mem_loc_descriptor failed.  Accept UNSPEC.
	(loc_descriptor): Use tls_mem_loc_descriptor for MEM.  For PARALLEL
	fail if one of the loc_descriptor calls for pieces failed.
	(loc_descriptor_from_tree_1): Handle even DECL_EXTERNAL __thread vars,
	as long as they bind locally.  For COMPONENT_REF, ARRAY_REF etc. fail
	if loc_descriptor_from_tree_1 on offset failed.

	* gcc.target/i386/pr37275.c: New test.

From-SVN: r140712