Re: [PATCH] i386[stv]: Handle REG_EH_REGION note

[Uros Bizjak <ubizjak@gmail.com>]

On Thu, Mar 14, 2024 at 8:32 AM Hongtao Liu <crazylht@gmail.com> wrote:
>
> On Thu, Mar 14, 2024 at 3:22 PM Uros Bizjak <ubizjak@gmail.com> wrote:
> >
> > On Thu, Mar 14, 2024 at 2:33 AM liuhongt <hongtao.liu@intel.com> wrote:
> > >
> > > When we split
> > > (insn 37 36 38 10 (set (reg:DI 104 [ _18 ])
> > >         (mem:DI (reg/f:SI 98 [ CallNative_nclosure.0_1 ]) [6 MEM[(struct SQRefCounted *)CallNative_nclosure.0_1]._uiRef+0 S8 A32])) "test.C":22:42 84 {*movdi_internal}
> > >      (expr_list:REG_EH_REGION (const_int -11 [0xfffffffffffffff5])
> > >
> > > into
> > >
> > > (insn 104 36 37 10 (set (subreg:V2DI (reg:DI 124) 0)
> > >         (vec_concat:V2DI (mem:DI (reg/f:SI 98 [ CallNative_nclosure.0_1 ]) [6 MEM[(struct SQRefCounted *)CallNative_nclosure.0_1]._uiRef+0 S8 A32])
> > >             (const_int 0 [0]))) "test.C":22:42 -1
> > >         (nil)))
> > > (insn 37 104 105 10 (set (subreg:V2DI (reg:DI 104 [ _18 ]) 0)
> > >         (subreg:V2DI (reg:DI 124) 0)) "test.C":22:42 2024 {movv2di_internal}
> > >      (expr_list:REG_EH_REGION (const_int -11 [0xfffffffffffffff5])
> > >         (nil)))
> > >
> > > we must copy the REG_EH_REGION note to the first insn and split the block
> > > after the newly added insn.  The REG_EH_REGION on the second insn will be
> > > removed later since it no longer traps.
> > >
> > > Currently we only handle memory_operand, are there any other insns
> > > need to be handled???
> >
> > I think memory access is the only thing that can trap.
> >
> > > Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,} for trunk and gcc-13/gcc-12 release branch.
> > > Ok for trunk and backport?
> > >
> > > gcc/ChangeLog:
> > >
> > >         * config/i386/i386-features.cc
> > >         (general_scalar_chain::convert_op): Handle REG_EH_REGION note.
> > >         (convert_scalars_to_vector): Ditto.
> > >         * config/i386/i386-features.h (class scalar_chain): New
> > >         memeber control_flow_insns.
> > >
> > > gcc/testsuite/ChangeLog:
> > >
> > >         * g++.target/i386/pr111822.C: New test.
> > > ---
> > >  gcc/config/i386/i386-features.cc         | 48 ++++++++++++++++++++++--
> > >  gcc/config/i386/i386-features.h          |  1 +
> > >  gcc/testsuite/g++.target/i386/pr111822.C | 45 ++++++++++++++++++++++
> > >  3 files changed, 90 insertions(+), 4 deletions(-)
> > >  create mode 100644 gcc/testsuite/g++.target/i386/pr111822.C
> > >
> > > diff --git a/gcc/config/i386/i386-features.cc b/gcc/config/i386/i386-features.cc
> > > index 1de2a07ed75..2ed27a9ebdd 100644
> > > --- a/gcc/config/i386/i386-features.cc
> > > +++ b/gcc/config/i386/i386-features.cc
> > > @@ -998,20 +998,36 @@ general_scalar_chain::convert_op (rtx *op, rtx_insn *insn)
> > >      }
> > >    else if (MEM_P (*op))
> > >      {
> > > +      rtx_insn* eh_insn, *movabs = NULL;
> > >        rtx tmp = gen_reg_rtx (GET_MODE (*op));
> > >
> > >        /* Handle movabs.  */
> > >        if (!memory_operand (*op, GET_MODE (*op)))
> > >         {
> > >           rtx tmp2 = gen_reg_rtx (GET_MODE (*op));
> > > +         movabs = emit_insn_before (gen_rtx_SET (tmp2, *op), insn);
> > >
> > > -         emit_insn_before (gen_rtx_SET (tmp2, *op), insn);
> > >           *op = tmp2;
> > >         }
> >
> > I may be missing something, but isn't the above a dead code? We have
> > if (MEM_p(*op)) and then if (!memory_operand (*op, ...)).
> It's PR91814 #c1, memory_operand will also check invalid memory addresses.

Oh, it is even my comment ;)

Perhaps the comment should be improved to something like:

"Emit MOVABS to load from a 64-bit absolute address to a GPR."

LGTM then.

Thanks,
Uros.

> >
> > Uros.
> >
> > >
> > > -      emit_insn_before (gen_rtx_SET (gen_rtx_SUBREG (vmode, tmp, 0),
> > > -                                    gen_gpr_to_xmm_move_src (vmode, *op)),
> > > -                       insn);
> > > +      eh_insn
> > > +       = emit_insn_before (gen_rtx_SET (gen_rtx_SUBREG (vmode, tmp, 0),
> > > +                                        gen_gpr_to_xmm_move_src (vmode, *op)),
> > > +                           insn);
> > > +
> > > +      if (cfun->can_throw_non_call_exceptions)
> > > +       {
> > > +         /* Handle REG_EH_REGION note.  */
> > > +         rtx note = find_reg_note (insn, REG_EH_REGION, NULL_RTX);
> > > +         if (note)
> > > +           {
> > > +             if (movabs)
> > > +               eh_insn = movabs;
> > > +             control_flow_insns.safe_push (eh_insn);
> > > +             add_reg_note (eh_insn, REG_EH_REGION, XEXP (note, 0));
> > > +           }
> > > +       }
> > > +
> > >        *op = gen_rtx_SUBREG (vmode, tmp, 0);
> > >
> > >        if (dump_file)
> > > @@ -2494,6 +2510,7 @@ convert_scalars_to_vector (bool timode_p)
> > >  {
> > >    basic_block bb;
> > >    int converted_insns = 0;
> > > +  auto_vec<rtx_insn *> control_flow_insns;
> > >
> > >    bitmap_obstack_initialize (NULL);
> > >    const machine_mode cand_mode[3] = { SImode, DImode, TImode };
> > > @@ -2575,6 +2592,11 @@ convert_scalars_to_vector (bool timode_p)
> > >                          chain->chain_id);
> > >             }
> > >
> > > +         rtx_insn* iter_insn;
> > > +         unsigned int ii;
> > > +         FOR_EACH_VEC_ELT (chain->control_flow_insns, ii, iter_insn)
> > > +           control_flow_insns.safe_push (iter_insn);
> > > +
> > >           delete chain;
> > >         }
> > >      }
> > > @@ -2643,6 +2665,24 @@ convert_scalars_to_vector (bool timode_p)
> > >                   DECL_INCOMING_RTL (parm) = gen_rtx_SUBREG (TImode, r, 0);
> > >               }
> > >           }
> > > +
> > > +      if (!control_flow_insns.is_empty ())
> > > +       {
> > > +         free_dominance_info (CDI_DOMINATORS);
> > > +
> > > +         unsigned int i;
> > > +         rtx_insn* insn;
> > > +         FOR_EACH_VEC_ELT (control_flow_insns, i, insn)
> > > +           if (control_flow_insn_p (insn))
> > > +             {
> > > +               /* Split the block after insn.  There will be a fallthru
> > > +                  edge, which is OK so we keep it.  We have to create
> > > +                  the exception edges ourselves.  */
> > > +               bb = BLOCK_FOR_INSN (insn);
> > > +               split_block (bb, insn);
> > > +               rtl_make_eh_edge (NULL, bb, BB_END (bb));
> > > +             }
> > > +       }
> > >      }
> > >
> > >    return 0;
> > > diff --git a/gcc/config/i386/i386-features.h b/gcc/config/i386/i386-features.h
> > > index 8bab2d8666d..b259cf679af 100644
> > > --- a/gcc/config/i386/i386-features.h
> > > +++ b/gcc/config/i386/i386-features.h
> > > @@ -155,6 +155,7 @@ class scalar_chain
> > >    hash_map<rtx, rtx> defs_map;
> > >    unsigned n_sse_to_integer;
> > >    unsigned n_integer_to_sse;
> > > +  auto_vec<rtx_insn *> control_flow_insns;
> > >
> > >    bool build (bitmap candidates, unsigned insn_uid, bitmap disallowed);
> > >    virtual int compute_convert_gain () = 0;
> > > diff --git a/gcc/testsuite/g++.target/i386/pr111822.C b/gcc/testsuite/g++.target/i386/pr111822.C
> > > new file mode 100644
> > > index 00000000000..d405387b23c
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.target/i386/pr111822.C
> > > @@ -0,0 +1,45 @@
> > > +/* PR target/111822 */
> > > +/* { dg-do compile } */
> > > +/* { dg-options "-O2 -flive-range-shrinkage -fno-dce -fnon-call-exceptions" } */
> > > +
> > > +typedef union {
> > > +  int *pNativeClosure;
> > > +  struct SQRefCounted *pRefCounted;
> > > +} SQObjectValue;
> > > +typedef struct {
> > > +  SQObjectValue _unVal;
> > > +} SQObject;
> > > +typedef long SQFUNCTION(struct SQVM *);
> > > +struct SQVM {
> > > +  void CallNative();
> > > +};
> > > +struct SQRefCounted {
> > > +  long long _uiRef;
> > > +};
> > > +void Null();
> > > +struct SQObjectPtr : SQObject {
> > > +  SQObjectPtr() {}
> > > +  SQObjectPtr(int *pNativeClosure) {
> > > +    _unVal.pNativeClosure = pNativeClosure;
> > > +    _unVal.pRefCounted->_uiRef++;
> > > +  }
> > > +  ~SQObjectPtr() { --_unVal.pRefCounted->_uiRef; }
> > > +};
> > > +struct CallInfo {
> > > +  SQObjectPtr _closure;
> > > +};
> > > +long long _top;
> > > +SQFUNCTION _function;
> > > +int *CallNative_nclosure;
> > > +void SQVM::CallNative() {
> > > +  long long oldtop = _top;
> > > +  CallInfo lci;
> > > +  lci._closure = CallNative_nclosure;
> > > +  try {
> > > +    _function(this);
> > > +  } catch (...) {
> > > +    _top = oldtop;
> > > +  }
> > > +  while (oldtop)
> > > +    Null();
> > > +}
> > > --
> > > 2.31.1
> > >
>
>
>
> --
> BR,
> Hongtao