static bool
forward_propagate_addr_expr (tree name, tree rhs)
{
  int stmt_loop_depth = gimple_bb (SSA_NAME_DEF_STMT (name))->loop_depth;
  imm_use_iterator iter;
  gimple use_stmt;
  bool all = true;
  bool single_use_p = has_single_use (name);

  FOR_EACH_IMM_USE_STMT (use_stmt, iter, name)
    {
      bool result;
      tree use_rhs;

      /* If the use is not in a simple assignment statement, then
	 there is nothing we can do.  */
      if (gimple_code (use_stmt) != GIMPLE_ASSIGN)
	{
	  if (!is_gimple_debug (use_stmt))
	    all = false;
	  continue;
	}

      /* If the use is in a deeper loop nest, then we do not want
	 to propagate the ADDR_EXPR into the loop as that is likely
	 adding expression evaluations into the loop.  */
      if (gimple_bb (use_stmt)->loop_depth > stmt_loop_depth)
	{
	  all = false;
	  continue;
	}

      {
	gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
	result = forward_propagate_addr_expr_1 (name, rhs, &gsi,
						single_use_p);
	/* If the use has moved to a different statement adjust
	   the update machinery for the old statement too.  */
	if (use_stmt != gsi_stmt (gsi))
	  {
	    update_stmt (use_stmt);
	    use_stmt = gsi_stmt (gsi);
	  }

	update_stmt (use_stmt);
      }
      all &= result;

      /* Remove intermediate now unused copy and conversion chains.  */
      use_rhs = gimple_assign_rhs1 (use_stmt);
      if (result
	  && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME
	  && TREE_CODE (use_rhs) == SSA_NAME
	  && has_zero_uses (gimple_assign_lhs (use_stmt)))
	{
	  gimple_stmt_iterator gsi = gsi_for_stmt (use_stmt);
	  release_defs (use_stmt);
	  gsi_remove (&gsi, true);
	}
    }
void
dump_immediate_uses_for (FILE *file, tree var)
{
  imm_use_iterator iter;
  use_operand_p use_p;

  gcc_assert (var && TREE_CODE (var) == SSA_NAME);

  print_generic_expr (file, var, TDF_SLIM);
  fprintf (file, " : -->");
  if (has_zero_uses (var))
    fprintf (file, " no uses.\n");
  else
    if (has_single_use (var))
      fprintf (file, " single use.\n");
    else
      fprintf (file, "%d uses.\n", num_imm_uses (var));

  FOR_EACH_IMM_USE_FAST (use_p, iter, var)
    {
      if (use_p->loc.stmt == NULL && use_p->use == NULL)
        fprintf (file, "***end of stmt iterator marker***\n");
      else
	if (!is_gimple_reg (USE_FROM_PTR (use_p)))
	  print_gimple_stmt (file, USE_STMT (use_p), 0, TDF_VOPS|TDF_MEMSYMS);
	else
	  print_gimple_stmt (file, USE_STMT (use_p), 0, TDF_SLIM);
    }
  fprintf(file, "\n");
}
Esempio n. 3
0
/* Check whether G is a potential conditional compare candidate.  */
static bool
ccmp_candidate_p (gimple *g)
{
  tree rhs = gimple_assign_rhs_to_tree (g);
  tree lhs, op0, op1;
  gimple *gs0, *gs1;
  enum tree_code tcode, tcode0, tcode1;
  tcode = TREE_CODE (rhs);

  if (tcode != BIT_AND_EXPR && tcode != BIT_IOR_EXPR)
    return false;

  lhs = gimple_assign_lhs (g);
  op0 = TREE_OPERAND (rhs, 0);
  op1 = TREE_OPERAND (rhs, 1);

  if ((TREE_CODE (op0) != SSA_NAME) || (TREE_CODE (op1) != SSA_NAME)
      || !has_single_use (lhs))
    return false;

  gs0 = get_gimple_for_ssa_name (op0);
  gs1 = get_gimple_for_ssa_name (op1);
  if (!gs0 || !gs1 || !is_gimple_assign (gs0) || !is_gimple_assign (gs1)
      /* g, gs0 and gs1 must be in the same basic block, since current stage
	 is out-of-ssa.  We can not guarantee the correctness when forwording
	 the gs0 and gs1 into g whithout DATAFLOW analysis.  */
      || gimple_bb (gs0) != gimple_bb (gs1)
      || gimple_bb (gs0) != gimple_bb (g))
    return false;

  if (!(INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (gs0)))
       || POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (gs0))))
      || !(INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (gs1)))
	   || POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (gs1)))))
    return false;

  tcode0 = gimple_assign_rhs_code (gs0);
  tcode1 = gimple_assign_rhs_code (gs1);
  if (TREE_CODE_CLASS (tcode0) == tcc_comparison
      && TREE_CODE_CLASS (tcode1) == tcc_comparison)
    return true;
  if (TREE_CODE_CLASS (tcode0) == tcc_comparison
      && ccmp_candidate_p (gs1))
    return true;
  else if (TREE_CODE_CLASS (tcode1) == tcc_comparison
	   && ccmp_candidate_p (gs0))
    return true;
  /* We skip ccmp_candidate_p (gs1) && ccmp_candidate_p (gs0) since
     there is no way to set the CC flag.  */
  return false;
}
Esempio n. 4
0
static gimple
get_prop_source_stmt (tree name, bool single_use_only, bool *single_use_p)
{
  bool single_use = true;

  do {
    gimple def_stmt = SSA_NAME_DEF_STMT (name);

    if (!has_single_use (name))
      {
	single_use = false;
	if (single_use_only)
	  return NULL;
      }

    /* If name is defined by a PHI node or is the default def, bail out.  */
    if (gimple_code (def_stmt) != GIMPLE_ASSIGN)
      return NULL;

    /* If name is not a simple copy destination, we found it.  */
    if (!gimple_assign_copy_p (def_stmt)
        || TREE_CODE (gimple_assign_rhs1 (def_stmt)) != SSA_NAME)
      {
	tree rhs;

	if (!single_use_only && single_use_p)
	  *single_use_p = single_use;

	/* We can look through pointer conversions in the search
	   for a useful stmt for the comparison folding.  */
	rhs = gimple_assign_rhs1 (def_stmt);
	if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
	    && TREE_CODE (rhs) == SSA_NAME
	    && POINTER_TYPE_P (TREE_TYPE (gimple_assign_lhs (def_stmt)))
	    && POINTER_TYPE_P (TREE_TYPE (rhs)))
	  name = rhs;
	else
	  return def_stmt;
      }
    else
      {
	/* Continue searching the def of the copy source name.  */
	name = gimple_assign_rhs1 (def_stmt);
      }
  } while (1);
}
Esempio n. 5
0
static tree
get_name_for_bit_test (tree candidate)
{
  /* Skip single-use names in favor of using the name from a
     non-widening conversion definition.  */
  if (TREE_CODE (candidate) == SSA_NAME
      && has_single_use (candidate))
    {
      gimple def_stmt = SSA_NAME_DEF_STMT (candidate);
      if (is_gimple_assign (def_stmt)
	  && CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
	{
	  if (TYPE_PRECISION (TREE_TYPE (candidate))
	      <= TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
	    return gimple_assign_rhs1 (def_stmt);
	}
    }

  return candidate;
}
Esempio n. 6
0
static inline bool
single_use (tree t)
{
  return TREE_CODE (t) != SSA_NAME || has_zero_uses (t) || has_single_use (t);
}
Esempio n. 7
0
static tree
rewrite_bittest (block_stmt_iterator *bsi)
{
  tree stmt, lhs, rhs, var, name, use_stmt, stmt1, stmt2, t;
  use_operand_p use;

  stmt = bsi_stmt (*bsi);
  lhs = GENERIC_TREE_OPERAND (stmt, 0);
  rhs = GENERIC_TREE_OPERAND (stmt, 1);

  /* Verify that the single use of lhs is a comparison against zero.  */
  if (TREE_CODE (lhs) != SSA_NAME
      || !single_imm_use (lhs, &use, &use_stmt)
      || TREE_CODE (use_stmt) != COND_EXPR)
    return stmt;
  t = COND_EXPR_COND (use_stmt);
  if (TREE_OPERAND (t, 0) != lhs
      || (TREE_CODE (t) != NE_EXPR
	  && TREE_CODE (t) != EQ_EXPR)
      || !integer_zerop (TREE_OPERAND (t, 1)))
    return stmt;

  /* Get at the operands of the shift.  The rhs is TMP1 & 1.  */
  stmt1 = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0));
  if (TREE_CODE (stmt1) != GIMPLE_MODIFY_STMT)
    return stmt;

  /* There is a conversion in between possibly inserted by fold.  */
  t = GIMPLE_STMT_OPERAND (stmt1, 1);
  if (TREE_CODE (t) == NOP_EXPR
      || TREE_CODE (t) == CONVERT_EXPR)
    {
      t = TREE_OPERAND (t, 0);
      if (TREE_CODE (t) != SSA_NAME
	  || !has_single_use (t))
	return stmt;
      stmt1 = SSA_NAME_DEF_STMT (t);
      if (TREE_CODE (stmt1) != GIMPLE_MODIFY_STMT)
	return stmt;
      t = GIMPLE_STMT_OPERAND (stmt1, 1);
    }

  /* Verify that B is loop invariant but A is not.  Verify that with
     all the stmt walking we are still in the same loop.  */
  if (TREE_CODE (t) == RSHIFT_EXPR
      && loop_containing_stmt (stmt1) == loop_containing_stmt (stmt)
      && outermost_invariant_loop_expr (TREE_OPERAND (t, 1),
                                        loop_containing_stmt (stmt1)) != NULL
      && outermost_invariant_loop_expr (TREE_OPERAND (t, 0),
                                        loop_containing_stmt (stmt1)) == NULL)
    {
      tree a = TREE_OPERAND (t, 0);
      tree b = TREE_OPERAND (t, 1);

      /* 1 << B */
      var = create_tmp_var (TREE_TYPE (a), "shifttmp");
      add_referenced_var (var);
      t = fold_build2 (LSHIFT_EXPR, TREE_TYPE (a),
		       build_int_cst (TREE_TYPE (a), 1), b);
      stmt1 = build_gimple_modify_stmt (var, t);
      name = make_ssa_name (var, stmt1);
      GIMPLE_STMT_OPERAND (stmt1, 0) = name;

      /* A & (1 << B) */
      t = fold_build2 (BIT_AND_EXPR, TREE_TYPE (a), a, name);
      stmt2 = build_gimple_modify_stmt (var, t);
      name = make_ssa_name (var, stmt2);
      GIMPLE_STMT_OPERAND (stmt2, 0) = name;

      /* Replace the SSA_NAME we compare against zero.  Adjust
	 the type of zero accordingly.  */
      SET_USE (use, name);
      TREE_OPERAND (COND_EXPR_COND (use_stmt), 1)
	= build_int_cst_type (TREE_TYPE (name), 0);

      bsi_insert_before (bsi, stmt1, BSI_SAME_STMT);
      bsi_replace (bsi, stmt2, true);

      return stmt1;
    }

  return stmt;
}
Esempio n. 8
0
static tree
forward_propagate_into_cond_1 (tree cond, tree *test_var_p)
{
  tree new_cond = NULL_TREE;
  enum tree_code cond_code = TREE_CODE (cond);
  tree test_var = NULL_TREE;
  tree def;
  tree def_rhs;

  /* If the condition is not a lone variable or an equality test of an
     SSA_NAME against an integral constant, then we do not have an
     optimizable case.

     Note these conditions also ensure the COND_EXPR has no
     virtual operands or other side effects.  */
  if (cond_code != SSA_NAME
      && !((cond_code == EQ_EXPR || cond_code == NE_EXPR)
	   && TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME
	   && CONSTANT_CLASS_P (TREE_OPERAND (cond, 1))
	   && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (cond, 1)))))
    return NULL_TREE;

  /* Extract the single variable used in the test into TEST_VAR.  */
  if (cond_code == SSA_NAME)
    test_var = cond;
  else
    test_var = TREE_OPERAND (cond, 0);

  /* Now get the defining statement for TEST_VAR.  Skip this case if
     it's not defined by some MODIFY_EXPR.  */
  def = SSA_NAME_DEF_STMT (test_var);
  if (TREE_CODE (def) != MODIFY_EXPR)
    return NULL_TREE;

  def_rhs = TREE_OPERAND (def, 1);

  /* If TEST_VAR is set by adding or subtracting a constant
     from an SSA_NAME, then it is interesting to us as we
     can adjust the constant in the conditional and thus
     eliminate the arithmetic operation.  */
  if (TREE_CODE (def_rhs) == PLUS_EXPR
      || TREE_CODE (def_rhs) == MINUS_EXPR)
    {
      tree op0 = TREE_OPERAND (def_rhs, 0);
      tree op1 = TREE_OPERAND (def_rhs, 1);

      /* The first operand must be an SSA_NAME and the second
	 operand must be a constant.  */
      if (TREE_CODE (op0) != SSA_NAME
	  || !CONSTANT_CLASS_P (op1)
	  || !INTEGRAL_TYPE_P (TREE_TYPE (op1)))
	return NULL_TREE;

      /* Don't propagate if the first operand occurs in
	 an abnormal PHI.  */
      if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op0))
	return NULL_TREE;

      if (has_single_use (test_var))
	{
	  enum tree_code new_code;
	  tree t;

	  /* If the variable was defined via X + C, then we must
	     subtract C from the constant in the conditional.
	     Otherwise we add C to the constant in the
	     conditional.  The result must fold into a valid
	     gimple operand to be optimizable.  */
	  new_code = (TREE_CODE (def_rhs) == PLUS_EXPR
		      ? MINUS_EXPR : PLUS_EXPR);
	  t = int_const_binop (new_code, TREE_OPERAND (cond, 1), op1, 0);
	  if (!is_gimple_val (t))
	    return NULL_TREE;

	  new_cond = build (cond_code, boolean_type_node, op0, t);
	}
    }

  /* These cases require comparisons of a naked SSA_NAME or
     comparison of an SSA_NAME against zero or one.  */
  else if (TREE_CODE (cond) == SSA_NAME
	   || integer_zerop (TREE_OPERAND (cond, 1))
	   || integer_onep (TREE_OPERAND (cond, 1)))
    {
      /* If TEST_VAR is set from a relational operation
	 between two SSA_NAMEs or a combination of an SSA_NAME
	 and a constant, then it is interesting.  */
      if (COMPARISON_CLASS_P (def_rhs))
	{
	  tree op0 = TREE_OPERAND (def_rhs, 0);
	  tree op1 = TREE_OPERAND (def_rhs, 1);

	  /* Both operands of DEF_RHS must be SSA_NAMEs or
	     constants.  */
	  if ((TREE_CODE (op0) != SSA_NAME
	       && !is_gimple_min_invariant (op0))
	      || (TREE_CODE (op1) != SSA_NAME
		  && !is_gimple_min_invariant (op1)))
	    return NULL_TREE;

	  /* Don't propagate if the first operand occurs in
	     an abnormal PHI.  */
	  if (TREE_CODE (op0) == SSA_NAME
	      && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op0))
	    return NULL_TREE;

	  /* Don't propagate if the second operand occurs in
	     an abnormal PHI.  */
	  if (TREE_CODE (op1) == SSA_NAME
	      && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op1))
	    return NULL_TREE;

	  if (has_single_use (test_var))
	    {
	      /* TEST_VAR was set from a relational operator.  */
	      new_cond = build (TREE_CODE (def_rhs),
				boolean_type_node, op0, op1);

	      /* Invert the conditional if necessary.  */
	      if ((cond_code == EQ_EXPR
		   && integer_zerop (TREE_OPERAND (cond, 1)))
		  || (cond_code == NE_EXPR
		      && integer_onep (TREE_OPERAND (cond, 1))))
		{
		  new_cond = invert_truthvalue (new_cond);

		  /* If we did not get a simple relational
		     expression or bare SSA_NAME, then we can
		     not optimize this case.  */
		  if (!COMPARISON_CLASS_P (new_cond)
		      && TREE_CODE (new_cond) != SSA_NAME)
		    new_cond = NULL_TREE;
		}
	    }
	}

      /* If TEST_VAR is set from a TRUTH_NOT_EXPR, then it
	 is interesting.  */
      else if (TREE_CODE (def_rhs) == TRUTH_NOT_EXPR)
	{
	  enum tree_code new_code;

	  def_rhs = TREE_OPERAND (def_rhs, 0);

	  /* DEF_RHS must be an SSA_NAME or constant.  */
	  if (TREE_CODE (def_rhs) != SSA_NAME
	      && !is_gimple_min_invariant (def_rhs))
	    return NULL_TREE;

	  /* Don't propagate if the operand occurs in
	     an abnormal PHI.  */
	  if (TREE_CODE (def_rhs) == SSA_NAME
	      && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (def_rhs))
	    return NULL_TREE;

	  if (cond_code == SSA_NAME
	      || (cond_code == NE_EXPR
		  && integer_zerop (TREE_OPERAND (cond, 1)))
	      || (cond_code == EQ_EXPR
		  && integer_onep (TREE_OPERAND (cond, 1))))
	    new_code = EQ_EXPR;
	  else
	    new_code = NE_EXPR;

	  new_cond = build2 (new_code, boolean_type_node, def_rhs,
			     fold_convert (TREE_TYPE (def_rhs),
					   integer_zero_node));
	}

      /* If TEST_VAR was set from a cast of an integer type
	 to a boolean type or a cast of a boolean to an
	 integral, then it is interesting.  */
      else if (TREE_CODE (def_rhs) == NOP_EXPR
	       || TREE_CODE (def_rhs) == CONVERT_EXPR)
	{
	  tree outer_type;
	  tree inner_type;

	  outer_type = TREE_TYPE (def_rhs);
	  inner_type = TREE_TYPE (TREE_OPERAND (def_rhs, 0));

	  if ((TREE_CODE (outer_type) == BOOLEAN_TYPE
	       && INTEGRAL_TYPE_P (inner_type))
	      || (TREE_CODE (inner_type) == BOOLEAN_TYPE
		  && INTEGRAL_TYPE_P (outer_type)))
	    ;
	  else if (INTEGRAL_TYPE_P (outer_type)
		   && INTEGRAL_TYPE_P (inner_type)
		   && TREE_CODE (TREE_OPERAND (def_rhs, 0)) == SSA_NAME
		   && ssa_name_defined_by_comparison_p (TREE_OPERAND (def_rhs,
								      0)))
	    ;
	  else
	    return NULL_TREE;

	  /* Don't propagate if the operand occurs in
	     an abnormal PHI.  */
	  if (TREE_CODE (TREE_OPERAND (def_rhs, 0)) == SSA_NAME
	      && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (TREE_OPERAND
						  (def_rhs, 0)))
	    return NULL_TREE;

	  if (has_single_use (test_var))
	    {
	      enum tree_code new_code;
	      tree new_arg;

	      if (cond_code == SSA_NAME
		  || (cond_code == NE_EXPR
		      && integer_zerop (TREE_OPERAND (cond, 1)))
		  || (cond_code == EQ_EXPR
		      && integer_onep (TREE_OPERAND (cond, 1))))
		new_code = NE_EXPR;
	      else
		new_code = EQ_EXPR;

	      new_arg = TREE_OPERAND (def_rhs, 0);
	      new_cond = build2 (new_code, boolean_type_node, new_arg,
				 fold_convert (TREE_TYPE (new_arg),
					       integer_zero_node));
	    }
	}
    }

  *test_var_p = test_var;
  return new_cond;
}
Esempio n. 9
0
static bool
factor_out_conditional_conversion (edge e0, edge e1, gphi *phi,
				   tree arg0, tree arg1)
{
  gimple arg0_def_stmt = NULL, arg1_def_stmt = NULL, new_stmt;
  tree new_arg0 = NULL_TREE, new_arg1 = NULL_TREE;
  tree temp, result;
  gphi *newphi;
  gimple_stmt_iterator gsi, gsi_for_def;
  source_location locus = gimple_location (phi);
  enum tree_code convert_code;

  /* Handle only PHI statements with two arguments.  TODO: If all
     other arguments to PHI are INTEGER_CST or if their defining
     statement have the same unary operation, we can handle more
     than two arguments too.  */
  if (gimple_phi_num_args (phi) != 2)
    return false;

  /* First canonicalize to simplify tests.  */
  if (TREE_CODE (arg0) != SSA_NAME)
    {
      std::swap (arg0, arg1);
      std::swap (e0, e1);
    }

  if (TREE_CODE (arg0) != SSA_NAME
      || (TREE_CODE (arg1) != SSA_NAME
	  && TREE_CODE (arg1) != INTEGER_CST))
    return false;

  /* Check if arg0 is an SSA_NAME and the stmt which defines arg0 is
     a conversion.  */
  arg0_def_stmt = SSA_NAME_DEF_STMT (arg0);
  if (!is_gimple_assign (arg0_def_stmt)
      || !gimple_assign_cast_p (arg0_def_stmt))
    return false;

  /* Use the RHS as new_arg0.  */
  convert_code = gimple_assign_rhs_code (arg0_def_stmt);
  new_arg0 = gimple_assign_rhs1 (arg0_def_stmt);
  if (convert_code == VIEW_CONVERT_EXPR)
    new_arg0 = TREE_OPERAND (new_arg0, 0);

  if (TREE_CODE (arg1) == SSA_NAME)
    {
      /* Check if arg1 is an SSA_NAME and the stmt which defines arg1
	 is a conversion.  */
      arg1_def_stmt = SSA_NAME_DEF_STMT (arg1);
      if (!is_gimple_assign (arg1_def_stmt)
	  || gimple_assign_rhs_code (arg1_def_stmt) != convert_code)
	return false;

      /* Use the RHS as new_arg1.  */
      new_arg1 = gimple_assign_rhs1 (arg1_def_stmt);
      if (convert_code == VIEW_CONVERT_EXPR)
	new_arg1 = TREE_OPERAND (new_arg1, 0);
    }
  else
    {
      /* If arg1 is an INTEGER_CST, fold it to new type.  */
      if (INTEGRAL_TYPE_P (TREE_TYPE (new_arg0))
	  && int_fits_type_p (arg1, TREE_TYPE (new_arg0)))
	{
	  if (gimple_assign_cast_p (arg0_def_stmt))
	    new_arg1 = fold_convert (TREE_TYPE (new_arg0), arg1);
	  else
	    return false;
	}
      else
	return false;
    }

  /*  If arg0/arg1 have > 1 use, then this transformation actually increases
      the number of expressions evaluated at runtime.  */
  if (!has_single_use (arg0)
      || (arg1_def_stmt && !has_single_use (arg1)))
    return false;

  /* If types of new_arg0 and new_arg1 are different bailout.  */
  if (!types_compatible_p (TREE_TYPE (new_arg0), TREE_TYPE (new_arg1)))
    return false;

  /* Create a new PHI stmt.  */
  result = PHI_RESULT (phi);
  temp = make_ssa_name (TREE_TYPE (new_arg0), NULL);
  newphi = create_phi_node (temp, gimple_bb (phi));

  if (dump_file && (dump_flags & TDF_DETAILS))
    {
      fprintf (dump_file, "PHI ");
      print_generic_expr (dump_file, gimple_phi_result (phi), 0);
      fprintf (dump_file,
	       " changed to factor conversion out from COND_EXPR.\n");
      fprintf (dump_file, "New stmt with CAST that defines ");
      print_generic_expr (dump_file, result, 0);
      fprintf (dump_file, ".\n");
    }

  /* Remove the old cast(s) that has single use.  */
  gsi_for_def = gsi_for_stmt (arg0_def_stmt);
  gsi_remove (&gsi_for_def, true);
  if (arg1_def_stmt)
    {
      gsi_for_def = gsi_for_s