[Bug tree-optimization/41244] "&data[i] - data" isn't converted to "i"

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=41244

--- Comment #4 from Marc Glisse <glisse at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #3)
> On the trunk (on aarch64) we get:

Yes, on I32P64 platforms we still have a chance to prove that the
multiplication doesn't overflow.

>   long int _4;
>   long int _5;
>   int _7;
>   sizetype _10;
> 
>   <bb 2>:
>   _10 = i_6(D) w* 4;

Ah, you actually get WIDEN_MULT_EXPR on aarch64? I essentially never saw it on
other platforms... x86_64 has

  _9 = (sizetype) i_6(D);
  _10 = _9 * 4;

instead.

>   _4 = (long int) _10;

Hmm, why doesn't that get combined with the WIDEN_MULT_EXPR? I would expect

  _4 = i_6(D) w* 4;

to be valid.

>   _5 = _4 /[ex] 4;
>   _7 = (int) _5;