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). Richard.