On Tue, 14 May 2024, Qing Zhao wrote: > > > > On May 14, 2024, at 13:14, Richard Biener <rguent...@suse.de> wrote: > > > > On Tue, 14 May 2024, Qing Zhao wrote: > > > >> > >> > >>> On May 14, 2024, at 10:29, Richard Biener <rguent...@suse.de> wrote: > >>> > > [...] > >>> It would of course > >>> need experimenting since we can end up moving stmts and merging blocks > >>> though the linear traces created by jump threading should be quite > >>> stable (as opposed to say the unrolling case where multiple instances > >>> of the loop body likely will end up in the exact same basic block). > >> > >> Do you mean, for loop unrolling the approach with one extra stmt for one > >> basic block might be even harder and unreliable? > > > > The question is whether the stmt marks the whole block or whether we > > for example add both a START and END stmt covering a copied path. > > I would guess for unrolling we need definitely need to do the latter > > (so we can diagnose "on the 3rd iteration of an unrolled loop" or > > similar). > > Okay. I see. > > Is it possible that the START and END stmts might be moved around and > out-of-place by the different optimizations?
There is nothign preventing stmts to be moved across START or END. Richard.
