On Thu, Oct 22, 2009 at 8:31 AM, Pranav Bhandarkar <pranav.bhandar...@gmail.com> wrote: > Hi, > > A possible silly question about the dead store elimination pass. From > the documentation it is clear that the store S1 below is removed by > this pass (in dse.c) > > *(addr) = value1; // S1 > ..... > ..... > *(addr) = value2 // S2 .. No read of "addr" between S1 and S2. > ...... > = *(addr) // Load > ....... > end_of_the_function > > However, consider a different example. > > *(addr) = value1; // S1 > ...... > ..... > end_of_the_function. > > i.e. there is no store Sn that follows S1 along any path from S1 to > the end of the function and there is no read of addr following S1 > either. Is the dse pass expected to remove such stores ? (I am > inclined to think that it should, but I am seeing a case where dse > doesnt remove such stores) . Further is the behaviour expected to be > different if the "addr" is based on "fp" ?
Are you talking about the tree dead-store elimination pass or the RTL one? Basically *addr = value1; cannot be removed if addr does not point to local memory or if the pointed-to memory escapes through a call-site that is dominated by this store. Richard.
