2017-02-16  Alan Modra  <amodra@gmail.com>

	PR rtl-optimization/79286
	* ira.c (def_dominates_uses): New function.
	(update_equiv_regs): Don't create an equivalence for insns that
	may trap where the register def does not dominate the use.

	* gcc.c-torture/execute/pr79286.c: New.

From-SVN: r245521