On Thu, 26 Sep 2024, Jeff Law wrote: > > > On 9/26/24 5:06 AM, Richard Biener wrote: > > When path isolation performs CFG manipulations (block splitting) it > > fails to update post-dominators it computes on-demand. That both > > runs into dominance verification issues when we compute post-dominators > > again and possibly accessing missing or broken post-dominance data > > when checking is disabled. The following attempts to get rid of > > post-dominator use by approximating always-executed with dominating > > function exit instead of post-dominating function entry. For this to > > work we have to add fake exit edges. > > > > Bootstrapped and tested on x86_64-unknown-linux-gnu. > > > > I'll push this later if nobody has comments. > > > > Thanks, > > Richard. > > > > PR tree-optimization/116850 > > * gimple-ssa-isolate-paths.cc (warn_return_addr_local): Use > > dominance and not post-dominance to compute maybe. > > (gimple_ssa_isolate_erroneous_paths): Add/remove fake exit edges. > > > > * gcc.dg/pr116850.c: New testcase. > So this phase doesn't really do any CFG manipulations, so I assume you're > referring to the other parts of path isolation mucking around with the CFG and > in turn causing mis-beavhior in the warn_return_addr_local path?
I think my work on sanitizing CFG cleanup made it necessary for this phase to start splitting blocks where it inserts traps() and that causes the issue. > My worry with "approximating always executed" is that we conditionally adjust > the return statement if !maybe. Yes, I've realized this and posted a followup instead delaying splitting the blocks. Richard.
