PR tree-optimization/58343
	* tree-ssa-threadupdate.c (thread_block): Identify and disable
	jump threading requests through loop headers buried in the middle
	of a jump threading path.

	* tree-ssa-threadedge.c (thread_around_empty_blocks): Fix thinko
	in return value/type.

	* gcc.c-torture/compile/pr58343.c: New test.

From-SVN: r202441