ICE with precompiled headers (GCC 8.1)

[Paul Smith]

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: