re PR rtl-optimization/41511 (combine behaves differently with/without -g)

re PR rtl-optimization/41511 (combine behaves differently with/without -g)

	PR rtl-optimization/41511
	* combine.c (record_value_for_reg): Pass explicit values as argument
	to get_last_value_validate.
	(get_last_value_validate): Document INSN parameter.
	For non-readonly MEMs, assume they might have been modified if INSN
	was in another basic block.
	(get_last_value): Minor reformatting.

Co-Authored-By: Jakub Jelinek <jakub@redhat.com>
From-SVN: r152459