[Bug tree-optimization/80345] [5 Regression] ICE in rewrite_use_nonlinear_expr with -O2

["amker at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80345

amker at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |amker at gcc dot gnu.org

--- Comment #12 from amker at gcc dot gnu.org ---
(In reply to Martin Liška from comment #11)
> (In reply to Martin Liška from comment #9)
> > Fixed on trunk (in between 5-base and 6-base) by r233269.
> 
> Unfortunately, simple back-porting of the patch does not work on gcc-5
> branch:
> 
> internal compiler error: in get_computation_aff, at
> tree-ssa-loop-ivopts.c:3129
>  fn2() { fn1(fn2); }
>  ^
> 0xe39a33 get_computation_aff
> 	../../gcc/tree-ssa-loop-ivopts.c:3129
> 0xe39d48 get_computation_at
> 	../../gcc/tree-ssa-loop-ivopts.c:3205
> 0xe39dba get_computation
> 	../../gcc/tree-ssa-loop-ivopts.c:3217
> 0xe421ba rewrite_use_nonlinear_expr
> 	../../gcc/tree-ssa-loop-ivopts.c:6459
> 0xe42c3a rewrite_use
> 	../../gcc/tree-ssa-loop-ivopts.c:6699
> 0xe42d13 rewrite_uses
> 	../../gcc/tree-ssa-loop-ivopts.c:6732
> 0xe43d16 tree_ssa_iv_optimize_loop
> 	../../gcc/tree-ssa-loop-ivopts.c:7062
> 0xe43dce tree_ssa_iv_optimize()
> 	../../gcc/tree-ssa-loop-ivopts.c:7094
> 
> Adding Bin Cheng.

The assertion depends on some other refactoring no on GCC 5 branch.  It should
be safe just remove that assertion on gcc 5, I will test a backport.

Thanks.