On Thu, Nov 13, 2025 at 12:17 PM Andrew Pinski
<[email protected]> wrote:
>
> On Thu, Nov 13, 2025 at 6:01 AM Richard Biener <[email protected]> wrote:
> >
> > We currently remove stmts inside of a FOR_EACH_IMM_USE_STMT iteration
> > which can be problematical. The following adjusts purge_all_uses
> > to gather all stmts to remove and remove them in reverse order
> > afterwards which also better deals with debug stmt generation.
> >
> > Bootstrapped and tested on x86_64-unknown-linux-gnu.
> >
> > OK?
>
> LGTM but I can't approve it.
Just FYI, I added a smallish (23 lines) testcase to the bug report
which should be small enough to add to the testsuite too.
Thanks,
Andrew
>
> >
> > Thanks,
> > Richard.
> >
> > PR ipa/122663
> > * ipa-param-manipulation.cc (purge_all_uses): Collect
> > stmts to remove and process that list in reverse.
> > ---
> > gcc/ipa-param-manipulation.cc | 13 +++++++++++--
> > 1 file changed, 11 insertions(+), 2 deletions(-)
> >
> > diff --git a/gcc/ipa-param-manipulation.cc b/gcc/ipa-param-manipulation.cc
> > index 11f843c48d1..96ab125dee1 100644
> > --- a/gcc/ipa-param-manipulation.cc
> > +++ b/gcc/ipa-param-manipulation.cc
> > @@ -636,6 +636,7 @@ purge_all_uses (tree name, hash_set <tree> *killed_ssas)
> > imm_use_iterator imm_iter;
> > gimple *stmt;
> > auto_vec <tree, 4> worklist;
> > + auto_vec <gimple *, 4> kill_list;
> >
> > worklist.safe_push (name);
> > while (!worklist.is_empty ())
> > @@ -664,11 +665,19 @@ purge_all_uses (tree name, hash_set <tree>
> > *killed_ssas)
> > if (!killed_ssas->add (lhs))
> > {
> > worklist.safe_push (lhs);
> > - gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
> > - gsi_remove (&gsi, true);
> > + kill_list.safe_push (stmt);
> > }
> > }
> > }
> > +
> > + /* Remove stmts in reverse and afterwards to properly handle debug stmt
> > + generation and to not interfere with immediate use iteration. */
> > + while (!kill_list.is_empty ())
> > + {
> > + stmt = kill_list.pop ();
> > + gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
> > + gsi_remove (&gsi, true);
> > + }
> > }
> >
> > /* Modify actual arguments of a function call in statement currently
> > belonging
> > --
> > 2.51.0
