Recompute domonators in DSE when removing dead edges (PR rtl-optimization/91164)

Hi!

When DSEing stmts with EH edges, we can invalidate through that dominator
info.  Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
ok for trunk?

2019-07-16  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/91164
	* dse.c (rest_of_handle_dse): If dead edges have been purged,
	invalidate dominance info.

	* g++.dg/opt/pr91164.C: New test.


	Jakub

On Tue, 16 Jul 2019, Jakub Jelinek wrote:

> Hi!
> 
> When DSEing stmts with EH edges, we can invalidate through that dominator
> info.  Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
> ok for trunk?

OK.

Richard.

> 2019-07-16  Jakub Jelinek  <jakub@redhat.com>
> 
> 	PR rtl-optimization/91164
> 	* dse.c (rest_of_handle_dse): If dead edges have been purged,
> 	invalidate dominance info.
> 
> 	* g++.dg/opt/pr91164.C: New test.
> 
> --- gcc/dse.c.jj	2019-07-10 15:52:56.753588824 +0200
> +++ gcc/dse.c	2019-07-15 12:26:05.264010493 +0200
> @@ -3621,7 +3621,10 @@ rest_of_handle_dse (void)
>    if ((locally_deleted || globally_deleted)
>        && cfun->can_throw_non_call_exceptions
>        && purge_all_dead_edges ())
> -    cleanup_cfg (0);
> +    {
> +      free_dominance_info (CDI_DOMINATORS);
> +      cleanup_cfg (0);
> +    }
>  
>    return 0;
>  }
> --- gcc/testsuite/g++.dg/opt/pr91164.C.jj	2019-07-15 13:03:56.449304956 +0200
> +++ gcc/testsuite/g++.dg/opt/pr91164.C	2019-07-15 13:04:58.641354884 +0200
> @@ -0,0 +1,89 @@
> +// PR rtl-optimization/91164
> +// { dg-do compile { target c++11 } }
> +// { dg-options "-O2 -fdelete-dead-exceptions -fnon-call-exceptions -fno-rerun-cse-after-loop -fno-tree-forwprop" }
> +
> +template <typename, typename = int> class b;
> +template <int v> struct d { static constexpr int e = v; };
> +template <bool, typename f> using g = f;
> +struct h { template <typename i> using j = i; };
> +template <typename, typename f> using k = h::j<f>;
> +void *operator new(__SIZE_TYPE__, void *);
> +struct l { l(); };
> +struct m;
> +template <typename n> n aa(m);
> +struct o { template <typename> using ab = l; };
> +template <typename, typename> struct b {
> +  struct q : o::ab<int> { q(int, l = l()) : p() {} int p; } ac;
> +  void ad();
> +  b() : ac(0) {}
> +  ~b() { bool r = ac.p == 0; if (r) ad(); }
> +  const wchar_t *ae();
> +};
> +struct m {};
> +struct t { virtual void f(); };
> +struct u { l a; };
> +struct af : t {
> +  struct ag { ag(l); };
> +  af(l ah) : ai(ah) {}
> +  ag ai;
> +};
> +struct w {
> +  template <typename f, typename x> w(f, x y) { new (0) af(y.a); }
> +};
> +struct z {
> +  using aj = int;
> +  template <typename x> z(x ah) : ak(al, ah) {}
> +  aj al;
> +  w ak;
> +};
> +struct am : z { template <typename x> am(x ah) : z(ah) {} };
> +template <typename, typename x> am an(x) { return u{}; }
> +template <typename> am ao() { return an<int>(l()); }
> +struct ap {
> +  k<int, int> aq;
> +  k<int, int> ar;
> +  k<int, int> as;
> +};
> +struct at { ap a; long au; ap av; ap aw; };
> +struct ax { at c; ax() : c() {} };
> +enum ay : int;
> +ay az, ba;
> +struct bb { bb(wchar_t *, wchar_t *, ay, m); };
> +template <typename bc> struct bd {
> +  typedef typename bc::be *bf;
> +  bd(bf, bf, const typename bc::bg &, ay);
> +  ay bh;
> +  bb bi;
> +  am bj;
> +  typename bc::bk e;
> +  ax bl;
> +  int bm;
> +};
> +template <typename, typename> using bn = g<d<false>::e, am>;
> +template <typename bc>
> +bd<bc>::bd(bf ah, bf y, const typename bc::bg &bu, ay)
> +    : bi(ah, y, bh, bu), bj(ao<bc>()), bm(aa<int>(bu)) {}
> +struct bt { typedef wchar_t be; typedef b<be> bk; typedef m bg; };
> +template <typename bc, typename bo> bn<bo, bc> bar();
> +template <typename bc, typename bo> bn<bo, bc> bq(bo) {
> +  typename bc::bg bp;
> +  auto bs = nullptr;
> +  using br = bd<bc>;
> +  br(bs, bs, bp, ba);
> +  return bar<bc, bo>();
> +}
> +struct bw {
> +  bw();
> +  template <typename bv, typename x> void assign(b<bv, x> ah) {
> +    const wchar_t by = *ah.ae();
> +    bw(&by, ah.ae(), bp, az);
> +  }
> +  template <typename bo> bw(bo, bo y, m, ay) : automaton(bq<bt>(y)) {}
> +  m bp;
> +  am automaton;
> +};
> +void bx() {
> +  b<wchar_t> s;
> +  bw ca;
> +  ca.assign(s);
> +}
> 
> 	Jakub
>