[Bug tree-optimization/112742] missed vectorization with src[a*b+i] where a*b is not int rather than same percission as size_type

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112742

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-11-28
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
The issue is that row*stride + col doesn't evolve with an affine function as
far as SCEV is concerned.

t.c:6:32: missed:  failed: evolution of base is not affine.

The "issue" is that we are dealing with pointer arithmetic here and the
row*stride + col can overflow but SCEV doesn't have "assumptions" we
could verify at runtime.

Use a signed 'stride', otherwise all arithmetic is promoted unsigned.

Duplicate of other similar bugs.