[Bug tree-optimization/126815] [17 Regression] internal compiler error: verify_flow_info failed caused by r17-3204-ge02ce3b8c4574c

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126815

--- Comment #8 from Drea Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Macleod from comment #7)
> (In reply to Drea Pinski from comment #4)
> > (In reply to Andrew Macleod from comment #3)
> > > yes, either leave the call, or I also have a patch in the queue which puts
> > > the _9 = 0 before the call instead of after.   This should be safe as there
> > > are known to be no other uses of _9
> > 
> > Before wont work for calls that returns-twice. So it is best not to change
> > it. Plus it saves slight memory and time .
> 
> eh? why wouldn't that work? There are zero uses of _9, so it doesn't matter
> if its the return value or not.
> 
> Regardless, your patch is fine.

Because returns_twice functions are required by the verifier to be the first
stmt of a basic block. So if you sre removing the lhs of a returns twice
functions inserting before the call will also ice. I didnt come up with a
testcase but I can add one if needed.