[PATCH] Fix UB in dse.c (PR rtl-optimization/85431)

[Jeff Law]

On 04/17/2018 02:57 PM, Jakub Jelinek wrote:
> Hi!
> 
> As mentioned, for BLKmode stores with MEM_SIZE of 0 we invoke UB,
> lowpart_bitmask (0) is called and that shifts an UHWI by 64.
> Zero size MEMs should only appear in inline asm and shouldn't be interesting
> to DSE at all, they can't make other stores dead, nor can be removed as dead
> themselves.
> 
> Fixed by just ignoring them.  Bootstrapped/regtested on x86_64-linux and
> i686-linux, ok for trunk?
> 
> 2018-04-17  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR rtl-optimization/85431
> 	* dse.c (record_store): Ignore zero width stores.
OK.
jeff