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?
My worry with "approximating always executed" is that we conditionally
adjust the return statement if !maybe.
jeff
