[Bug tree-optimization/42586] New: load-modify-store on x86 should be \ single instruction

[pinskia at gcc dot gnu dot org]

------- Comment #14 from pinskia at gcc dot gnu dot org  2010-01-03 07:10 -------
If we manually do the SRA like SRA would do it in 4.4:
  unsigned char *a, *b, *c;
  a = sptr->curr;
  b = sptr->base;
  c = sptr->last_plus_one;
  a +=4294967295U;
  sptr->curr = a;
  sptr->base = b;
  sptr->last_plus_one = c;

We get the behavior you want.  This is why I said this is all interrelated. 
PRE is able to remove the stores at the tree level on the trunk which then it
looks like what I showed in comment #3.  Again this is all the same issue
really.  And there is no need to file more bugs about the same issue.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42586