cfgcleanup: Fix -fcompare-debug issue in outgoing_edges_match [PR100254]

Hi!

The following testcase fails with -fcompare-debug.  The problem is that
outgoing_edges_match behaves differently between -g0 and -g, if
some load/store with REG_EH_REGION is followed by DEBUG_INSNs, the
REG_EH_REGION check is not done, while when there are no DEBUG_INSNs, it is
done.

We already compute last1 and last2 as BB_END (bb{1,2}) with skipped debug
insns and notes, so this patch just uses those.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2021-04-27  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/100254
	* cfgcleanup.c (outgoing_edges_match): Check REG_EH_REGION on
	last1 and last2 insns rather than BB_END (bb1) and BB_END (bb2) insns.

	* g++.dg/opt/pr100254.C: New test.


	Jakub

On Tue, 27 Apr 2021, Jakub Jelinek wrote:

> Hi!
> 
> The following testcase fails with -fcompare-debug.  The problem is that
> outgoing_edges_match behaves differently between -g0 and -g, if
> some load/store with REG_EH_REGION is followed by DEBUG_INSNs, the
> REG_EH_REGION check is not done, while when there are no DEBUG_INSNs, it is
> done.
> 
> We already compute last1 and last2 as BB_END (bb{1,2}) with skipped debug
> insns and notes, so this patch just uses those.
> 
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

OK.

Thanks,
Richard.

> 2021-04-27  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR rtl-optimization/100254
> 	* cfgcleanup.c (outgoing_edges_match): Check REG_EH_REGION on
> 	last1 and last2 insns rather than BB_END (bb1) and BB_END (bb2) insns.
> 
> 	* g++.dg/opt/pr100254.C: New test.
> 
> --- gcc/cfgcleanup.c.jj	2021-01-04 10:25:39.318228332 +0100
> +++ gcc/cfgcleanup.c	2021-04-26 12:24:05.276792318 +0200
> @@ -1885,8 +1885,8 @@ outgoing_edges_match (int mode, basic_bl
>  
>    /* Ensure the same EH region.  */
>    {
> -    rtx n1 = find_reg_note (BB_END (bb1), REG_EH_REGION, 0);
> -    rtx n2 = find_reg_note (BB_END (bb2), REG_EH_REGION, 0);
> +    rtx n1 = find_reg_note (last1, REG_EH_REGION, 0);
> +    rtx n2 = find_reg_note (last2, REG_EH_REGION, 0);
>  
>      if (!n1 && n2)
>        return false;
> --- gcc/testsuite/g++.dg/opt/pr100254.C.jj	2021-04-26 12:31:02.557080936 +0200
> +++ gcc/testsuite/g++.dg/opt/pr100254.C	2021-04-26 12:30:38.412353829 +0200
> @@ -0,0 +1,101 @@
> +// PR rtl-optimization/100254
> +// { dg-do compile }
> +// { dg-options "-O2 -fno-guess-branch-probability -fipa-pta -fnon-call-exceptions -fcompare-debug" }
> +// { dg-additional-options "-mtune=goldmont" { target i?86-*-* x86_64-*-* } }
> +
> +struct _Rb_tree_node_base {
> +  typedef _Rb_tree_node_base *_Base_ptr;
> +  typedef _Rb_tree_node_base *_Const_Base_ptr;
> +  _Base_ptr _M_left;
> +};
> +template <typename _Key_compare> struct _Rb_tree_key_compare {
> +  _Key_compare _M_key_compare;
> +};
> +struct _Rb_tree_header {
> +  _Rb_tree_node_base _M_header;
> +};
> +struct _Rb_tree_iterator {
> +  _Rb_tree_iterator(_Rb_tree_node_base::_Base_ptr);
> +  friend bool operator==(_Rb_tree_iterator, _Rb_tree_iterator);
> +};
> +template <typename _Tp> struct _Rb_tree_const_iterator {
> +  typedef _Rb_tree_const_iterator _Self;
> +  _Rb_tree_const_iterator(_Rb_tree_node_base::_Const_Base_ptr) {}
> +  _Tp operator*();
> +  template <typename _Up>
> +  friend bool operator!=(_Rb_tree_const_iterator<_Up>, _Rb_tree_const_iterator<_Up>);
> +};
> +template <typename _Key, typename _Val, typename _Compare> struct _Rb_tree {
> +  template <typename _Key_compare>
> +  struct _Rb_tree_impl : _Rb_tree_key_compare<_Key_compare>, _Rb_tree_header {};
> +  _Rb_tree_impl<_Compare> _M_impl;
> +  _Key _S_key();
> +  typedef _Rb_tree_const_iterator<_Val> const_iterator;
> +  const_iterator begin() { return _M_impl._M_header._M_left; }
> +  _Rb_tree_iterator find(const _Key &);
> +};
> +template <typename _Key, typename _Val, typename _Compare>
> +_Rb_tree_iterator _Rb_tree<_Key, _Val, _Compare>::find(const _Key &__k) {
> +  _Rb_tree_iterator __j = 0;
> +  return __j == 0 || _M_impl._M_key_compare(__k, _S_key()) ? 0 : __j;
> +}
> +template <typename _Key, typename _Compare = _Key> struct set {
> +  typedef _Key key_type;
> +  typedef _Rb_tree<key_type, _Key, _Compare> _Rep_type;
> +  _Rep_type _M_t;
> +  typedef typename _Rep_type::const_iterator iterator;
> +  iterator begin() { return _M_t.begin(); }
> +  iterator end();
> +  void find(key_type __x) { _M_t.find(__x); }
> +};
> +struct WindowDesc {
> +  WindowDesc(short);
> +} _station_view_desc(0);
> +struct Window {
> +  void IsWidgetLowered();
> +  virtual void OnClick(int, int, int);
> +};
> +int AllocateWindowDescFront_window_number;
> +template <typename Wcls> void AllocateWindowDescFront(WindowDesc *desc, bool) {
> +  Wcls(desc, AllocateWindowDescFront_window_number);
> +}
> +class CargoDataEntry;
> +struct CargoSorter {
> +  bool operator()(const CargoDataEntry *, const CargoDataEntry *) const;
> +};
> +struct CargoDataEntry {
> +  ~CargoDataEntry();
> +  char Retrieve_cargo;
> +  void Retrieve() {
> +    CargoDataEntry t(Retrieve_cargo);
> +    children->find(&t);
> +  }
> +  CargoDataEntry(char);
> +  set<CargoDataEntry *, CargoSorter> *children;
> +};
> +CargoDataEntry::CargoDataEntry(char) : children() {}
> +CargoDataEntry::~CargoDataEntry() {
> +  if (children)
> +    for (set<CargoDataEntry *>::iterator i = children->begin();
> +         i != children->end();)
> +      delete *i;
> +}
> +bool CargoSorter::operator()(const CargoDataEntry *,
> +                             const CargoDataEntry *) const { return false; }
> +struct StationViewWindow : Window {
> +  StationViewWindow(WindowDesc *, int);
> +  CargoDataEntry HandleCargoWaitingClick_filter;
> +  void OnClick(int, int widget, int) {
> +    switch (widget) {
> +    case 0:
> +      HandleCargoWaitingClick_filter.Retrieve();
> +      HandleCargoWaitingClick_filter.Retrieve();
> +    case 1:
> +      IsWidgetLowered();
> +    }
> +  }
> +};
> +void ShowStationViewWindow_station() {
> +  AllocateWindowDescFront<StationViewWindow>(&_station_view_desc,
> +                                             ShowStationViewWindow_station);
> +}
> 
> 	Jakub
> 
>