This is a regression present on the mainline, 7 and 6 branches, in the form of an ICE during tree-ccp, which is confused by a type witn zero precision. Tested on x86_64-suse-linux, applied on mainline, 7 and 6 branches. 2017-09-05 Eric Botcazou * gcc-interface/utils.c (unchecked_convert): When the result type is a non-biased integral type with size 0, set the result to 0 directly. 2017-09-05 Eric Botcazou * gnat.dg/specs/uc2.ads: New test. -- Eric Botcazou