https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65519
--- Comment #9 from Eric Botcazou <ebotcazou at gcc dot gnu.org> --- > gimple-fold works like fold - it tries to re-simplify what you feed it, but > only the outermost level (so it doesn't really recurse). Still I think this > bug needs changing code-generation like with the attached patch which I am > testing right now. I see, thanks. > I always forget how to force SJLJ EH on x86_64-linux for ada so I didn't > manage to reproduce the issue or check if the patch fixes it ... In a build tree: eric@polaris:~/build/gcc/native> cp gcc/ada/rts/system.ads . Edit system.ads and change ZCX_By_Default to False. Then compile the reduced testcase: eric@polaris:~/build/gcc/native> gcc/xgcc -Bgcc -S p.ads -O2 Unable to coalesce ssa_names 2 and 87 which are marked as MUST COALESCE. I.3_2(ab) and I.3_87(ab) +===========================GNAT BUG DETECTED==============================+ | 5.0.0 20150316 (experimental) [trunk revision 221457] (x86_64-suse-linux) GCC error:| | SSA corruption | | Error detected around p.ads:6:9