[Bug tree-optimization/113210] [14 Regression] ICE: tree check: expected integer_cst, have cond_expr in get_len, at tree.h:6481

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113210

--- Comment #13 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #12)
> (In reply to Jakub Jelinek from comment #11)
> > (In reply to Richard Biener from comment #9)
> > > That is, another fix might be to adjust NITERSM1 to NITERS - 1 when
> > > NITERS went constant ...  (btw, I want to get rid of _NITERS and only
> > 
> > Or we could only use fold_build2 for the PLUS_EXPR 1 computation if NITERSM1
> > is INTEGER_CST, otherwise use build2...
> 
> I think we should see where the original expression is built but not folded.

Hmm, probably in estimate_numbers_of_iterations,

      if (TREE_CODE (niter_desc.may_be_zero) != INTEGER_CST)
        niter = build3 (COND_EXPR, type, niter_desc.may_be_zero,
                        build_int_cst (type, 0),
                        niter);

I vaguely remember code trying to pattern match the COND_EXPR created
by this (though it should instead use number_of_iterations_exit).  It
should be safe to replace the above with fold_build3.