> On Thu, Feb 08 2024, Martin Jambor wrote:
> > Hi,
> >
> > PR 113757 shows that the code which was meant to debug-reset and
> > remove SSAs defined by LHSs of calls redirected to
> > __builtin_unreachable can trigger also when speculative
> > devirtualization creates a call to a noreturn function (and since it
> > is noreturn, it does not bother dealing with its return value).
> >
> > What is more, it seems that the code handling this case is not really
> > necessary. I feel slightly idiotic about this because I have a
> > feeling that I added it because of a failing test-case but I can
> > neither find the testcase nor a reason why the code in
> > cgraph_edge::redirect_call_stmt_to_callee would not be sufficient (it
> > turns the SSA name into a default-def, a bit like IPA-SRA, but any
> > code dominated by a call to a noreturn is not dangerous when it comes
> > to its side-effects). So this patch just removes the handling.
> >
> > Bootstrapped and tested on x86_64-linux and ppc64le-linux. I have also
> > LTO-bootstrapped and LTO-profilebootstrapped the patch on x86_64-linux.
> >
> > OK for master?
> >
> > Thanks,
> >
> > Martin
> >
> >
> > gcc/ChangeLog:
> >
> > 2024-02-07 Martin Jambor <mjam...@suse.cz>
> >
> > PR ipa/113757
> > * tree-inline.cc (redirect_all_calls): Remove code adding SSAs to
> > id->killed_new_ssa_names.
> >
> > gcc/testsuite/ChangeLog:
> >
> > 2024-02-07 Martin Jambor <mjam...@suse.cz>
> >
> > PR ipa/113757
> > * g++.dg/ipa/pr113757.C: New test.
OK,
thanks!
Honza
> > ---
> > gcc/testsuite/g++.dg/ipa/pr113757.C | 14 ++++++++++++++
> > gcc/tree-inline.cc | 14 ++------------
> > 2 files changed, 16 insertions(+), 12 deletions(-)
> > create mode 100644 gcc/testsuite/g++.dg/ipa/pr113757.C
> >
> > diff --git a/gcc/testsuite/g++.dg/ipa/pr113757.C
> > b/gcc/testsuite/g++.dg/ipa/pr113757.C
> > new file mode 100644
> > index 00000000000..885d4010a10
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/ipa/pr113757.C
> > @@ -0,0 +1,14 @@
> > +// { dg-do compile }
> > +// { dg-options "-O2 -fPIC" }
> > +// { dg-require-effective-target fpic }
> > +
> > +long size();
> > +struct ll { virtual int hh(); };
> > +ll *slice_owner;
> > +int ll::hh() { __builtin_exit(0); }
> > +int nn() {
> > + if (size())
> > + return 0;
> > + return slice_owner->hh();
> > +}
> > +int (*a)() = nn;
> > diff --git a/gcc/tree-inline.cc b/gcc/tree-inline.cc
> > index 75c10eb7dfc..cac41b4f031 100644
> > --- a/gcc/tree-inline.cc
> > +++ b/gcc/tree-inline.cc
> > @@ -2984,23 +2984,13 @@ redirect_all_calls (copy_body_data * id,
> > basic_block bb)
> > gimple *stmt = gsi_stmt (si);
> > if (is_gimple_call (stmt))
> > {
> > - tree old_lhs = gimple_call_lhs (stmt);
> > struct cgraph_edge *edge = id->dst_node->get_edge (stmt);
> > if (edge)
> > {
> > if (!id->killed_new_ssa_names)
> > id->killed_new_ssa_names = new hash_set<tree> (16);
> > - gimple *new_stmt
> > - = cgraph_edge::redirect_call_stmt_to_callee (edge,
> > - id->killed_new_ssa_names);
> > - if (old_lhs
> > - && TREE_CODE (old_lhs) == SSA_NAME
> > - && !gimple_call_lhs (new_stmt))
> > - /* In case of IPA-SRA removing the LHS, the name should have
> > - been already added to the hash. But in case of redirecting
> > - to builtin_unreachable it was not and the name still should
> > - be pruned from debug statements. */
> > - id->killed_new_ssa_names->add (old_lhs);
> > + cgraph_edge::redirect_call_stmt_to_callee (edge,
> > + id->killed_new_ssa_names);
> >
> > if (stmt == last && id->call_stmt && maybe_clean_eh_stmt (stmt))
> > gimple_purge_dead_eh_edges (bb);
> > --
> > 2.43.0
