On Fri, Oct 21, 2011 at 2:22 PM, William J. Schmidt <wschm...@linux.vnet.ibm.com> wrote: > > > On Fri, 2011-10-21 at 11:26 +0200, Richard Guenther wrote: >> On Tue, Oct 18, 2011 at 4:14 PM, William J. Schmidt >> <wschm...@linux.vnet.ibm.com> wrote: > > <snip> > >> > + >> > + /* We don't use get_def_for_expr for S1 because TER doesn't forward >> > + S1 in some situations where this transform is useful, such as >> > + when S1 is the base of two MEM_REFs fitting the pattern. */ >> > + s1_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (exp, 0)); >> >> You can't do this - this will possibly generate wrong code. You _do_ >> have to use get_def_for_expr. Or do it when we are still in "true" SSA >> form... >> >> Richard. >> > > OK. get_def_for_expr always returns NULL here for the cases I was > targeting, so doing this in expand isn't going to be helpful. > > Rather than cram this in somewhere else upstream, it might be better to > just wait and let this case be handled by the new strength reduction > pass. This is one of the easy cases with explicit multiplies in the > instruction stream, so it shouldn't require any special handling there. > Seem reasonable?
Yes, sure. Richard. > Bill > >
