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

[Hongtao Liu <crazylht@gmail.com>]

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.
>
> 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