re PR rtl-optimization/61094 (-O3 insn Internal compiler error in copyprop_hardreg_forward_1, at regcprop.c:775)

	PR rtl-optimization/61094
	* ree.c (combine_reaching_defs): Do not reextend an insn if it
	was marked as do_no_reextend.  If a copy is needed to eliminate
	an extension, then mark it as do_not_reextend.

	PR rtl-optimization/61094
	* g++.dg/pr61094: New test.

From-SVN: r211142