re PR tree-optimization/83668 (wrong code with -O -fno-tree-dominator-opts -fgraphite...

re PR tree-optimization/83668 (wrong code with -O -fno-tree-dominator-opts -fgraphite-identity)

2018-01-09  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/83668
	* graphite.c (canonicalize_loop_closed_ssa): Add edge argument,
	move prologue...
	(canonicalize_loop_form): ... here, renamed from ...
	(canonicalize_loop_closed_ssa_form): ... this and amended to
	swap successor edges for loop exit blocks to make us use
	the RPO order we need for initial schedule generation.

	* gcc.dg/graphite/pr83668.c: New testcase.

From-SVN: r256381