I was able to reproduce this with GCC 9.0.1 20190430 as well. It appears that adding -MD to the PCH build sometimes causes the "deps" data in the PCH file to be empty, but this is never noticed unless you use the -fpch-deps option on the source compile line: if you don't do this then nothing in GCC will try to access that pointer.
I feel like I've hit the end of what I can do with tracking this down, so I filed https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90306 Although I couldn't create a repro case, I can reproduce it here on some systems so if someone wants me to investigate further I'm happy to do that: please provide some pointers/advice for debugging. On Wed, 2019-05-01 at 10:56 -0400, Paul Smith wrote: > On Wed, 2019-05-01 at 09:35 -0400, Paul Smith wrote: > > > Unfortunately my GCC is heavily optimized and stripped so backtraces > > > are useless. I will generate a debuggable GCC and see if I can get > > > more info on the ICE. > > > > I have created a GCC with debug enabled so I'll see what I find. > > I was able to reproduce this ICE quite readily with my debuggable GCC > 8.1.0. Here's the failure:
