Fix latent LRA remat issue (PR68730)

Fix latent LRA remat issue (PR68730)

	PR rtl-optimization/68730
	* lra-remat.c (insn_to_cand_activation): New static variable.
	(lra_remat): Allocate and free it.
	(create_cand): New arg activation. Initialize a field in
	insn_to_cand_activation if it is nonnull.
	(create_cands): Pass the activation insn to create_cand when making
	a candidate involving an output reload.  Reorganize code a little.
	(do_remat): Keep track of active status of candidates in a separate
	bitmap.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@233215 138bc75d-0d04-0410-961f-82ee72b054a4