backport patch to fix PR65048

PR tree-optimization/65048
	* tree-ssa-threadupdate.c (valid_jump_thread_path): New.
	(thread_through_all_blocks): Call valid_jump_thread_path.      Remove invalid
	FSM jump-thread paths.

 PR tree-optimization/65048
 * gcc.dg/tree-ssa/ssa-dom-thread-9.c: New.
2 files changed
tree: 22bc0625401e4f1eb473c944b11bc9dadc48d2c2
  1. gcc-4.8/
  2. gcc-4.9/
  3. build-gcc.sh
  4. build.py