re PR rtl-optimization/52573 (regrename creates overlapping register allocations for output operands)

	PR rtl-optimization/52573
        * regrename.c (build_def_use): Ignore REG_DEAD notes if there is
        a REG_UNUSED for the same register.

	* gcc.dg/pr52573.c: New test.

From-SVN: r195288