re PR middle-end/32897 (Invalid rematerialisation of subregs)

gcc/
	PR middle-end/32897
	* reload.c (find_reloads): Check that the memory returned by
	find_reloads_toplev was not the result of forcing a constant
	to memory.
	(find_reloads_toplev): Always use simplify_gen_subreg to get
	the subreg of a constant.  If the result is also a constant,
	but not a legitimate one, force it into the constant pool
	and reload its address.

gcc/testsuite/
	* gcc.dg/torture/pr32897.c: New test.

From-SVN: r127536