https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113607
--- Comment #20 from JuzheZhong <juzhe.zhong at rivai dot ai> ---
(In reply to Robin Dapp from comment #19)
> What seems odd to me is that in fre5 we simplify
>
> _429 = .COND_SHL (mask_patt_205.47_276, vect_cst__262, vect_cst__262, { 0,
> ... });
> vect_prephitmp_129.51_282 = _429;
> vect_iftmp.55_287 = VEC_COND_EXPR <mask_patt_209.54_286,
> vect_prephitmp_129.51_282, vect_cst__262>;
>
> to
>
> Applying pattern match.pd:9607, gimple-match-10.cc:3817
> gimple_simplified to vect_iftmp.55_287 = .COND_SHL (mask_patt_205.47_276,
> vect_cst__262, vect_cst__262, { 0, ... });
>
> so fold
>
> vec_cond (mask209, prephitmp129, vect_cst262)
> with prephitmp129 = cond_shl (mask205, vect_cst262, vect_cst262, 0)
>
> into
> cond_shl = (mask205, vect_cst262, vect_cst262, 0)?
>
> That doesn't look valid to me because the vec_cond's else value
> (vect_cst262) gets lost. Wouldn't such a simplification have a conditional
> else value?
> Like !mask1 ? else1 : else2 instead of else2 unconditionally?
Does ARM SVE have the same issue too ? Since I think we should be using same
folding optimization as ARM SVE.
