re PR bootstrap/80887 (gnat bootstrap fails at s-regpat.o: raised STORAGE_ERROR : stack overflow or erroneous memory access)

	PR bootstrap/80887
	2017-05-25  Marc Glisse  <marc.glisse@inria.fr>

	* match.pd ((A +- CST1) +- CST2): Allow some conversions.

	* gcc.dg/tree-ssa/addadd.c: Xfail all scan-tree-dump*.

From-SVN: r248533