Re: fold: &a[i1] + c * i2 -> &a[i1 + i2] messing up types

[Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>]

Hello,

> > I don't think it is a good idea.  TYPE argument of
> > try_move_mult_to_index really should be type of the arguments it works
> > with, or you are creating a nasty hack and source for other possible
> > bugs.
> 
> Well, the type argument is only used for constructing the ADDR_EXPR
> which has to match TREE_TYPE (addr) due to checking constraints.  So
> we could equally omit that argument.  Or give it the meaning I read
> into the functions comment:
> 
> /* Tries to replace &a[idx] CODE s * delta with &a[idx CODE delta], if s
> is
>    step of the array.  TYPE is the type of the expression.  ADDR is the
> address.
>    MULT is the multiplicative expression.  If the function succeeds, the
> new
>    address expression is returned.  Otherwise NULL_TREE is returned.  */
> 
> namely, that we want a tree of type "type" which is the type of the
> whole expression, not of the ADDR_EXPR.  But just working around this
> possible redundant argument in the callers seems wrong to me, too.
> 
> If you prefer removing the type argument that would be fine, too.

this might be a good idea, yes.

Zdenek