re PR middle-end/55263 (ICE: pre_and_rev_post_order_compute, at cfganal.c:875 with -O -fgcse-after-reload -fnon-call-exceptions)

gcc/
	PR middle-end/55263
	* postreload.c (rest_of_handle_postreload): With non-call exceptions,
	if edges are purged call cleanup_cfg to remove unreachable blocks.

testsuite/
	PR middle-end/55263
	* g++.dg/pr55263.C: New test.

From-SVN: r193412