On Thu, Sep 06, 2018 at 12:11:09PM -0600, Jeff Law wrote: > On 09/05/2018 06:11 AM, Richard Biener wrote: > > On Wed, Sep 5, 2018 at 2:01 PM Ilya Leoshkevich <i...@linux.ibm.com> wrote: > >> + /* Combining insns can change basic blocks in a way that they end up > >> + containing a single jump_insn. This creates an opportunity to > >> improve code > >> + with jump threading. */ > >> + cleanup_cfg (CLEANUP_THREADING);
Please show an example of when this happens. For almost all code it does not happen, so please don't do it always. Does it improve code at all? There is a reason we do not run the expensive cfg cleanups after every pass: they are expensive. They are only done in some strategically chosen places. Segher
