re PR rtl-optimization/11741 (internal compiler error at gcse.c:5318)

re PR rtl-optimization/11741 (internal compiler error at gcse.c:5318)

	PR optimization/11741
	* gcse.c (pre_insert_copy_insn): Tweak the logic for finding the
	appropriate set to match that in hash_scan_insn.  Fall back to
	the original copy method, if we can't validate changing insn.
	(pre_delete): Only delete instructions that have a single_set,
	instead of aborting when we encounter an PARALLEL insn with more
	then one SET.

	* gcc.dg/20030926-1.c: New test case.

From-SVN: r71827