re PR rtl-optimization/51495 (ICE: in force_nonfallthru_and_redirect, at cfgrtl.c:1171 with computed goto)

	PR rtl-optimization/51495
	* function.c (thread_prologue_and_epilogue_insns): Don't add
	to bb_tail basic blocks that have EDGE_COMPLEX predecessor edges
	from basic blocks not needing prologue.

	* gcc.c-torture/compile/pr51495.c: New test.

From-SVN: r182265