[Bug rtl-optimization/78038] [5/6/7 Regression] internal compiler error: in get_sub_rtx, at ree.c:655

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78038

--- Comment #5 from ktkachov at gcc dot gnu.org ---
(In reply to Steffen Schmidt from comment #0)
> Created attachment 39840 [details]
> Test source file
> 
> Dear GCC maintainers,
> 
> we found that gcc / g++ crashes with internal compiler error in get_sub_rtx,
> at ree.c:655 at optimization level -O2
> Target plattform is aarch64-elf, in detail -march=armv8-a -mabi=ilp32
> 
> It seems the the order of the statements, especially the call to a function
> pointer and use of global register variable is important. Unfortunately I
> could not determine a dedicated optimization option causing the problem.
> 

By the way, the optimisation in which the ICE occurs is ree (redundant
extension elimination). You can turn it off by adding -fno-ree to the flags.