PR tree-optimization/59221
	* tree-ssa-threadedge.c (thread_across_edge): Properly manage
	temporary equivalences when threading through joiner blocks.

	PR tree-optimization/59221
	* gcc.c-torture/execute/pr59221.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@205229 138bc75d-0d04-0410-961f-82ee72b054a4