[PATCH] Fix PR43560

[Zdenek Dvorak]

Hi,

> This fixes PR43560, loop store motion does not properly distinguish
> between trapping loads and trapping stores, thus it can happen that
> store motion is executed on a readonly variable.  The following
> patch fixes that by making sure a store is always executed in case
> a possibly trapping memory is store-motioned.  Also readonly
> memory locations are assumed as trapping.
> 
> Bootstrapped and tested on x86_64-unknown-linux-gnu.
> 
> Comments?

looks ok to me,

Zdenek