gimplify.c

	      tree factor
		= size_int (DECL_OFFSET_ALIGN (field) / BITS_PER_UNIT);

	      /* Divide the offset by its alignment.  */
	      offset = size_binop_loc (loc, EXACT_DIV_EXPR, offset, factor);

	      if (!is_gimple_min_invariant (offset))
		{
		  TREE_OPERAND (t, 2) = offset;
		  tret = gimplify_expr (&TREE_OPERAND (t, 2), pre_p,
					post_p, is_gimple_reg,
					fb_rvalue);
		  ret = MIN (ret, tret);
		}
	    }
	  else
	    {
	      tret = gimplify_expr (&TREE_OPERAND (t, 2), pre_p, post_p,
				    is_gimple_reg, fb_rvalue);
	      ret = MIN (ret, tret);
	    }
	}
    }

  /* Step 2 is to gimplify the base expression.  Make sure lvalue is set
     so as to match the min_lval predicate.  Failure to do so may result
     in the creation of large aggregate temporaries.  */
  tret = gimplify_expr (p, pre_p, post_p, is_gimple_min_lval,
			fallback | fb_lvalue);
  ret = MIN (ret, tret);

  /* And finally, the indices and operands of ARRAY_REF.  During this
     loop we also remove any useless conversions.  */
  for (; expr_stack.length () > 0; )
    {
      tree t = expr_stack.pop ();

      if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
	{
	  /* Gimplify the dimension.  */
	  if (!is_gimple_min_invariant (TREE_OPERAND (t, 1)))
	    {
	      tret = gimplify_expr (&TREE_OPERAND (t, 1), pre_p, post_p,
				    is_gimple_val, fb_rvalue);
	      ret = MIN (ret, tret);
	    }
	}

      STRIP_USELESS_TYPE_CONVERSION (TREE_OPERAND (t, 0));

      /* The innermost expression P may have originally had
	 TREE_SIDE_EFFECTS set which would have caused all the outer
	 expressions in *EXPR_P leading to P to also have had
	 TREE_SIDE_EFFECTS set.  */
      recalculate_side_effects (t);
    }

  /* If the outermost expression is a COMPONENT_REF, canonicalize its type.  */
  if ((fallback & fb_rvalue) && TREE_CODE (*expr_p) == COMPONENT_REF)
    {
      canonicalize_component_ref (expr_p);
    }

  expr_stack.release ();

  gcc_assert (*expr_p == expr || ret != GS_ALL_DONE);

  return ret;
}

/*  Gimplify the self modifying expression pointed to by EXPR_P
    (++, --, +=, -=).

    PRE_P points to the list where side effects that must happen before
	*EXPR_P should be stored.

    POST_P points to the list where side effects that must happen after
	*EXPR_P should be stored.

    WANT_VALUE is nonzero iff we want to use the value of this expression
	in another expression.

    ARITH_TYPE is the type the computation should be performed in.  */

enum gimplify_status
gimplify_self_mod_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
			bool want_value, tree arith_type)
{
  enum tree_code code;
  tree lhs, lvalue, rhs, t1;
  gimple_seq post = NULL, *orig_post_p = post_p;
  bool postfix;
  enum tree_code arith_code;
  enum gimplify_status ret;
  location_t loc = EXPR_LOCATION (*expr_p);

  code = TREE_CODE (*expr_p);

  gcc_assert (code == POSTINCREMENT_EXPR || code == POSTDECREMENT_EXPR
	      || code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR);

  /* Prefix or postfix?  */
  if (code == POSTINCREMENT_EXPR || code == POSTDECREMENT_EXPR)
    /* Faster to treat as prefix if result is not used.  */
    postfix = want_value;
  else
    postfix = false;

  /* For postfix, make sure the inner expression's post side effects
     are executed after side effects from this expression.  */
  if (postfix)
    post_p = &post;

  /* Add or subtract?  */
  if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
    arith_code = PLUS_EXPR;
  else
    arith_code = MINUS_EXPR;

  /* Gimplify the LHS into a GIMPLE lvalue.  */
  lvalue = TREE_OPERAND (*expr_p, 0);
  ret = gimplify_expr (&lvalue, pre_p, post_p, is_gimple_lvalue, fb_lvalue);
  if (ret == GS_ERROR)
    return ret;

  /* Extract the operands to the arithmetic operation.  */
  lhs = lvalue;
  rhs = TREE_OPERAND (*expr_p, 1);

  /* For postfix operator, we evaluate the LHS to an rvalue and then use
     that as the result value and in the postqueue operation.  */
  if (postfix)
    {
      ret = gimplify_expr (&lhs, pre_p, post_p, is_gimple_val, fb_rvalue);
      if (ret == GS_ERROR)
	return ret;

      lhs = get_initialized_tmp_var (lhs, pre_p, NULL);
    }

  /* For POINTERs increment, use POINTER_PLUS_EXPR.  */
  if (POINTER_TYPE_P (TREE_TYPE (lhs)))
    {
      rhs = convert_to_ptrofftype_loc (loc, rhs);
      if (arith_code == MINUS_EXPR)
	rhs = fold_build1_loc (loc, NEGATE_EXPR, TREE_TYPE (rhs), rhs);
      t1 = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (*expr_p), lhs, rhs);
    }
  else
    t1 = fold_convert (TREE_TYPE (*expr_p),
		       fold_build2 (arith_code, arith_type,
				    fold_convert (arith_type, lhs),
				    fold_convert (arith_type, rhs)));

  if (postfix)
    {
      gimplify_assign (lvalue, t1, pre_p);
      gimplify_seq_add_seq (orig_post_p, post);
      *expr_p = lhs;
      return GS_ALL_DONE;
    }
  else
    {
      *expr_p = build2 (MODIFY_EXPR, TREE_TYPE (lvalue), lvalue, t1);
      return GS_OK;
    }
}

/* If *EXPR_P has a variable sized type, wrap it in a WITH_SIZE_EXPR.  */

static void
maybe_with_size_expr (tree *expr_p)
{
  tree expr = *expr_p;
  tree type = TREE_TYPE (expr);
  tree size;

  /* If we've already wrapped this or the type is error_mark_node, we can't do
     anything.  */
  if (TREE_CODE (expr) == WITH_SIZE_EXPR
      || type == error_mark_node)
    return;

  /* If the size isn't known or is a constant, we have nothing to do.  */
  size = TYPE_SIZE_UNIT (type);
  if (!size || poly_int_tree_p (size))
    return;

  /* Otherwise, make a WITH_SIZE_EXPR.  */
  size = unshare_expr (size);
  size = SUBSTITUTE_PLACEHOLDER_IN_EXPR (size, expr);
  *expr_p = build2 (WITH_SIZE_EXPR, type, expr, size);
}

/* Helper for gimplify_call_expr.  Gimplify a single argument *ARG_P
   Store any side-effects in PRE_P.  CALL_LOCATION is the location of
   the CALL_EXPR.  If ALLOW_SSA is set the actual parameter may be
   gimplified to an SSA name.  */

enum gimplify_status
gimplify_arg (tree *arg_p, gimple_seq *pre_p, location_t call_location,
	      bool allow_ssa)
{
  bool (*test) (tree);
  fallback_t fb;

  /* In general, we allow lvalues for function arguments to avoid
     extra overhead of copying large aggregates out of even larger
     aggregates into temporaries only to copy the temporaries to
     the argument list.  Make optimizers happy by pulling out to
     temporaries those types that fit in registers.  */
  if (is_gimple_reg_type (TREE_TYPE (*arg_p)))
    test = is_gimple_val, fb = fb_rvalue;
  else
    {
      test = is_gimple_lvalue, fb = fb_either;
      /* Also strip a TARGET_EXPR that would force an extra copy.  */
      if (TREE_CODE (*arg_p) == TARGET_EXPR)
	{
	  tree init = TARGET_EXPR_INITIAL (*arg_p);
	  if (init
	      && !VOID_TYPE_P (TREE_TYPE (init)))
	    *arg_p = init;
	}
    }

  /* If this is a variable sized type, we must remember the size.  */
  maybe_with_size_expr (arg_p);

  /* FIXME diagnostics: This will mess up gcc.dg/Warray-bounds.c.  */
  /* Make sure arguments have the same location as the function call
     itself.  */
  protected_set_expr_location (*arg_p, call_location);

  /* There is a sequence point before a function call.  Side effects in
     the argument list must occur before the actual call. So, when
     gimplifying arguments, force gimplify_expr to use an internal
     post queue which is then appended to the end of PRE_P.  */
  return gimplify_expr (arg_p, pre_p, NULL, test, fb, allow_ssa);
}

/* Don't fold inside offloading or taskreg regions: it can break code by
   adding decl references that weren't in the source.  We'll do it during
   omplower pass instead.  */

static bool
maybe_fold_stmt (gimple_stmt_iterator *gsi)
{
  struct gimplify_omp_ctx *ctx;
  for (ctx = gimplify_omp_ctxp; ctx; ctx = ctx->outer_context)
    if ((ctx->region_type & (ORT_TARGET | ORT_PARALLEL | ORT_TASK)) != 0)
      return false;
    else if ((ctx->region_type & ORT_HOST_TEAMS) == ORT_HOST_TEAMS)
      return false;
  /* Delay folding of builtins until the IL is in consistent state
     so the diagnostic machinery can do a better job.  */
  if (gimple_call_builtin_p (gsi_stmt (*gsi)))
    return false;
  return fold_stmt (gsi);
}

/* Gimplify the CALL_EXPR node *EXPR_P into the GIMPLE sequence PRE_P.
   WANT_VALUE is true if the result of the call is desired.  */

static enum gimplify_status
gimplify_call_expr (tree *expr_p, gimple_seq *pre_p, bool want_value)
{
  tree fndecl, parms, p, fnptrtype;
  enum gimplify_status ret;
  int i, nargs;
  gcall *call;
  bool builtin_va_start_p = false;
  location_t loc = EXPR_LOCATION (*expr_p);

  gcc_assert (TREE_CODE (*expr_p) == CALL_EXPR);

  /* For reliable diagnostics during inlining, it is necessary that
     every call_expr be annotated with file and line.  */
  if (! EXPR_HAS_LOCATION (*expr_p))
    SET_EXPR_LOCATION (*expr_p, input_location);

  /* Gimplify internal functions created in the FEs.  */
  if (CALL_EXPR_FN (*expr_p) == NULL_TREE)
    {
      if (want_value)
	return GS_ALL_DONE;

      nargs = call_expr_nargs (*expr_p);
      enum internal_fn ifn = CALL_EXPR_IFN (*expr_p);
      auto_vec<tree> vargs (nargs);

      for (i = 0; i < nargs; i++)
	{
	  gimplify_arg (&CALL_EXPR_ARG (*expr_p, i), pre_p,
			EXPR_LOCATION (*expr_p));
	  vargs.quick_push (CALL_EXPR_ARG (*expr_p, i));
	}

      gcall *call = gimple_build_call_internal_vec (ifn, vargs);
      gimple_call_set_nothrow (call, TREE_NOTHROW (*expr_p));
      gimplify_seq_add_stmt (pre_p, call);
      return GS_ALL_DONE;
    }

  /* This may be a call to a builtin function.

     Builtin function calls may be transformed into different
     (and more efficient) builtin function calls under certain
     circumstances.  Unfortunately, gimplification can muck things
     up enough that the builtin expanders are not aware that certain
     transformations are still valid.

     So we attempt transformation/gimplification of the call before
     we gimplify the CALL_EXPR.  At this time we do not manage to
     transform all calls in the same manner as the expanders do, but
     we do transform most of them.  */
  fndecl = get_callee_fndecl (*expr_p);
  if (fndecl && fndecl_built_in_p (fndecl, BUILT_IN_NORMAL))
    switch (DECL_FUNCTION_CODE (fndecl))
      {
      CASE_BUILT_IN_ALLOCA:
	/* If the call has been built for a variable-sized object, then we
	   want to restore the stack level when the enclosing BIND_EXPR is
	   exited to reclaim the allocated space; otherwise, we precisely
	   need to do the opposite and preserve the latest stack level.  */
	if (CALL_ALLOCA_FOR_VAR_P (*expr_p))
	  gimplify_ctxp->save_stack = true;
	else
	  gimplify_ctxp->keep_stack = true;
	break;

      case BUILT_IN_VA_START:
        {
	  builtin_va_start_p = TRUE;
	  if (call_expr_nargs (*expr_p) < 2)
	    {
	      error ("too few arguments to function %<va_start%>");
	      *expr_p = build_empty_stmt (EXPR_LOCATION (*expr_p));
	      return GS_OK;
	    }

	  if (fold_builtin_next_arg (*expr_p, true))
	    {
	      *expr_p = build_empty_stmt (EXPR_LOCATION (*expr_p));
	      return GS_OK;
	    }
	  break;
	}

      case BUILT_IN_EH_RETURN:
	cfun->calls_eh_return = true;
	break;

      default:
        ;
      }
  if (fndecl && fndecl_built_in_p (fndecl))
    {
      tree new_tree = fold_call_expr (input_location, *expr_p, !want_value);
      if (new_tree && new_tree != *expr_p)
	{
	  /* There was a transformation of this call which computes the
	     same value, but in a more efficient way.  Return and try
	     again.  */
	  *expr_p = new_tree;
	  return GS_OK;
	}
    }

  /* Remember the original function pointer type.  */
  fnptrtype = TREE_TYPE (CALL_EXPR_FN (*expr_p));

  /* There is a sequence point before the call, so any side effects in
     the calling expression must occur before the actual call.  Force
     gimplify_expr to use an internal post queue.  */
  ret = gimplify_expr (&CALL_EXPR_FN (*expr_p), pre_p, NULL,
		       is_gimple_call_addr, fb_rvalue);

  nargs = call_expr_nargs (*expr_p);

  /* Get argument types for verification.  */
  fndecl = get_callee_fndecl (*expr_p);
  parms = NULL_TREE;
  if (fndecl)
    parms = TYPE_ARG_TYPES (TREE_TYPE (fndecl));
  else
    parms = TYPE_ARG_TYPES (TREE_TYPE (fnptrtype));

  if (fndecl && DECL_ARGUMENTS (fndecl))
    p = DECL_ARGUMENTS (fndecl);
  else if (parms)
    p = parms;
  else
    p = NULL_TREE;
  for (i = 0; i < nargs && p; i++, p = TREE_CHAIN (p))
    ;

  /* If the last argument is __builtin_va_arg_pack () and it is not
     passed as a named argument, decrease the number of CALL_EXPR
     arguments and set instead the CALL_EXPR_VA_ARG_PACK flag.  */
  if (!p
      && i < nargs
      && TREE_CODE (CALL_EXPR_ARG (*expr_p, nargs - 1)) == CALL_EXPR)
    {
      tree last_arg = CALL_EXPR_ARG (*expr_p, nargs - 1);
      tree last_arg_fndecl = get_callee_fndecl (last_arg);

      if (last_arg_fndecl
	  && fndecl_built_in_p (last_arg_fndecl, BUILT_IN_VA_ARG_PACK))
	{
	  tree call = *expr_p;

	  --nargs;
	  *expr_p = build_call_array_loc (loc, TREE_TYPE (call),
					  CALL_EXPR_FN (call),
					  nargs, CALL_EXPR_ARGP (call));

	  /* Copy all CALL_EXPR flags, location and block, except
	     CALL_EXPR_VA_ARG_PACK flag.  */
	  CALL_EXPR_STATIC_CHAIN (*expr_p) = CALL_EXPR_STATIC_CHAIN (call);
	  CALL_EXPR_TAILCALL (*expr_p) = CALL_EXPR_TAILCALL (call);
	  CALL_EXPR_RETURN_SLOT_OPT (*expr_p)
	    = CALL_EXPR_RETURN_SLOT_OPT (call);
	  CALL_FROM_THUNK_P (*expr_p) = CALL_FROM_THUNK_P (call);
	  SET_EXPR_LOCATION (*expr_p, EXPR_LOCATION (call));

	  /* Set CALL_EXPR_VA_ARG_PACK.  */
	  CALL_EXPR_VA_ARG_PACK (*expr_p) = 1;
	}
    }

  /* If the call returns twice then after building the CFG the call
     argument computations will no longer dominate the call because
     we add an abnormal incoming edge to the call.  So do not use SSA
     vars there.  */
  bool returns_twice = call_expr_flags (*expr_p) & ECF_RETURNS_TWICE;

  /* Gimplify the function arguments.  */
  if (nargs > 0)
    {
      for (i = (PUSH_ARGS_REVERSED ? nargs - 1 : 0);
           PUSH_ARGS_REVERSED ? i >= 0 : i < nargs;
           PUSH_ARGS_REVERSED ? i-- : i++)
        {
          enum gimplify_status t;

          /* Avoid gimplifying the second argument to va_start, which needs to
             be the plain PARM_DECL.  */
          if ((i != 1) || !builtin_va_start_p)
            {
              t = gimplify_arg (&CALL_EXPR_ARG (*expr_p, i), pre_p,
				EXPR_LOCATION (*expr_p), ! returns_twice);

              if (t == GS_ERROR)
                ret = GS_ERROR;
            }
        }
    }

  /* Gimplify the static chain.  */
  if (CALL_EXPR_STATIC_CHAIN (*expr_p))
    {
      if (fndecl && !DECL_STATIC_CHAIN (fndecl))
	CALL_EXPR_STATIC_CHAIN (*expr_p) = NULL;
      else
	{
	  enum gimplify_status t;
	  t = gimplify_arg (&CALL_EXPR_STATIC_CHAIN (*expr_p), pre_p,
			    EXPR_LOCATION (*expr_p), ! returns_twice);
	  if (t == GS_ERROR)
	    ret = GS_ERROR;
	}
    }

  /* Verify the function result.  */
  if (want_value && fndecl
      && VOID_TYPE_P (TREE_TYPE (TREE_TYPE (fnptrtype))))
    {
      error_at (loc, "using result of function returning %<void%>");
      ret = GS_ERROR;
    }

  /* Try this again in case gimplification exposed something.  */
  if (ret != GS_ERROR)
    {
      tree new_tree = fold_call_expr (input_location, *expr_p, !want_value);

      if (new_tree && new_tree != *expr_p)
	{
	  /* There was a transformation of this call which computes the
	     same value, but in a more efficient way.  Return and try
	     again.  */
	  *expr_p = new_tree;
	  return GS_OK;
	}
    }
  else
    {
      *expr_p = error_mark_node;
      return GS_ERROR;
    }

  /* If the function is "const" or "pure", then clear TREE_SIDE_EFFECTS on its
     decl.  This allows us to eliminate redundant or useless
     calls to "const" functions.  */
  if (TREE_CODE (*expr_p) == CALL_EXPR)
    {
      int flags = call_expr_flags (*expr_p);
      if (flags & (ECF_CONST | ECF_PURE)
	  /* An infinite loop is considered a side effect.  */
	  && !(flags & (ECF_LOOPING_CONST_OR_PURE)))
	TREE_SIDE_EFFECTS (*expr_p) = 0;
    }

  /* If the value is not needed by the caller, emit a new GIMPLE_CALL
     and clear *EXPR_P.  Otherwise, leave *EXPR_P in its gimplified
     form and delegate the creation of a GIMPLE_CALL to
     gimplify_modify_expr.  This is always possible because when
     WANT_VALUE is true, the caller wants the result of this call into
     a temporary, which means that we will emit an INIT_EXPR in
     internal_get_tmp_var which will then be handled by
     gimplify_modify_expr.  */
  if (!want_value)
    {
      /* The CALL_EXPR in *EXPR_P is already in GIMPLE form, so all we
	 have to do is replicate it as a GIMPLE_CALL tuple.  */
      gimple_stmt_iterator gsi;
      call = gimple_build_call_from_tree (*expr_p, fnptrtype);
      notice_special_calls (call);
      gimplify_seq_add_stmt (pre_p, call);
      gsi = gsi_last (*pre_p);
      maybe_fold_stmt (&gsi);
      *expr_p = NULL_TREE;
    }
  else
    /* Remember the original function type.  */
    CALL_EXPR_FN (*expr_p) = build1 (NOP_EXPR, fnptrtype,
				     CALL_EXPR_FN (*expr_p));

  return ret;
}

/* Handle shortcut semantics in the predicate operand of a COND_EXPR by
   rewriting it into multiple COND_EXPRs, and possibly GOTO_EXPRs.

   TRUE_LABEL_P and FALSE_LABEL_P point to the labels to jump to if the
   condition is true or false, respectively.  If null, we should generate
   our own to skip over the evaluation of this specific expression.

   LOCUS is the source location of the COND_EXPR.

   This function is the tree equivalent of do_jump.

   shortcut_cond_r should only be called by shortcut_cond_expr.  */

static tree
shortcut_cond_r (tree pred, tree *true_label_p, tree *false_label_p,
		 location_t locus)
{
  tree local_label = NULL_TREE;
  tree t, expr = NULL;

  /* OK, it's not a simple case; we need to pull apart the COND_EXPR to
     retain the shortcut semantics.  Just insert the gotos here;
     shortcut_cond_expr will append the real blocks later.  */
  if (TREE_CODE (pred) == TRUTH_ANDIF_EXPR)
    {
      location_t new_locus;

      /* Turn if (a && b) into

	 if (a); else goto no;
	 if (b) goto yes; else goto no;
	 (no:) */

      if (false_label_p == NULL)
	false_label_p = &local_label;

      /* Keep the original source location on the first 'if'.  */
      t = shortcut_cond_r (TREE_OPERAND (pred, 0), NULL, false_label_p, locus);
      append_to_statement_list (t, &expr);

      /* Set the source location of the && on the second 'if'.  */
      new_locus = rexpr_location (pred, locus);
      t = shortcut_cond_r (TREE_OPERAND (pred, 1), true_label_p, false_label_p,
			   new_locus);
      append_to_statement_list (t, &expr);
    }
  else if (TREE_CODE (pred) == TRUTH_ORIF_EXPR)
    {
      location_t new_locus;

      /* Turn if (a || b) into

	 if (a) goto yes;
	 if (b) goto yes; else goto no;
	 (yes:) */

      if (true_label_p == NULL)
	true_label_p = &local_label;

      /* Keep the original source location on the first 'if'.  */
      t = shortcut_cond_r (TREE_OPERAND (pred, 0), true_label_p, NULL, locus);
      append_to_statement_list (t, &expr);

      /* Set the source location of the || on the second 'if'.  */
      new_locus = rexpr_location (pred, locus);
      t = shortcut_cond_r (TREE_OPERAND (pred, 1), true_label_p, false_label_p,
			   new_locus);
      append_to_statement_list (t, &expr);
    }
  else if (TREE_CODE (pred) == COND_EXPR
	   && !VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (pred, 1)))
	   && !VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (pred, 2))))
    {
      location_t new_locus;

      /* As long as we're messing with gotos, turn if (a ? b : c) into
	 if (a)
	   if (b) goto yes; else goto no;
	 else
	   if (c) goto yes; else goto no;

	 Don't do this if one of the arms has void type, which can happen
	 in C++ when the arm is throw.  */

      /* Keep the original source location on the first 'if'.  Set the source
	 location of the ? on the second 'if'.  */
      new_locus = rexpr_location (pred, locus);
      expr = build3 (COND_EXPR, void_type_node, TREE_OPERAND (pred, 0),
		     shortcut_cond_r (TREE_OPERAND (pred, 1), true_label_p,
				      false_label_p, locus),
		     shortcut_cond_r (TREE_OPERAND (pred, 2), true_label_p,
				      false_label_p, new_locus));
    }
  else
    {
      expr = build3 (COND_EXPR, void_type_node, pred,
		     build_and_jump (true_label_p),
		     build_and_jump (false_label_p));
      SET_EXPR_LOCATION (expr, locus);
    }

  if (local_label)
    {
      t = build1 (LABEL_EXPR, void_type_node, local_label);
      append_to_statement_list (t, &expr);
    }

  return expr;
}

/* If EXPR is a GOTO_EXPR, return it.  If it is a STATEMENT_LIST, skip
   any of its leading DEBUG_BEGIN_STMTS and recurse on the subsequent
   statement, if it is the last one.  Otherwise, return NULL.  */

static tree
find_goto (tree expr)
{
  if (!expr)
    return NULL_TREE;

  if (TREE_CODE (expr) == GOTO_EXPR)
    return expr;

  if (TREE_CODE (expr) != STATEMENT_LIST)
    return NULL_TREE;

  tree_stmt_iterator i = tsi_start (expr);

  while (!tsi_end_p (i) && TREE_CODE (tsi_stmt (i)) == DEBUG_BEGIN_STMT)
    tsi_next (&i);

  if (!tsi_one_before_end_p (i))
    return NULL_TREE;

  return find_goto (tsi_stmt (i));
}

/* Same as find_goto, except that it returns NULL if the destination
   is not a LABEL_DECL.  */

static inline tree
find_goto_label (tree expr)
{
  tree dest = find_goto (expr);
  if (dest && TREE_CODE (GOTO_DESTINATION (dest)) == LABEL_DECL)
    return dest;
  return NULL_TREE;
}

/* Given a conditional expression EXPR with short-circuit boolean
   predicates using TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR, break the
   predicate apart into the equivalent sequence of conditionals.  */

static tree
shortcut_cond_expr (tree expr)
{
  tree pred = TREE_OPERAND (expr, 0);
  tree then_ = TREE_OPERAND (expr, 1);
  tree else_ = TREE_OPERAND (expr, 2);
  tree true_label, false_label, end_label, t;
  tree *true_label_p;
  tree *false_label_p;
  bool emit_end, emit_false, jump_over_else;
  bool then_se = then_ && TREE_SIDE_EFFECTS (then_);
  bool else_se = else_ && TREE_SIDE_EFFECTS (else_);

  /* First do simple transformations.  */
  if (!else_se)
    {
      /* If there is no 'else', turn
	   if (a && b) then c
	 into
	   if (a) if (b) then c.  */
      while (TREE_CODE (pred) == TRUTH_ANDIF_EXPR)
	{
	  /* Keep the original source location on the first 'if'.  */
	  location_t locus = EXPR_LOC_OR_LOC (expr, input_location);
	  TREE_OPERAND (expr, 0) = TREE_OPERAND (pred, 1);
	  /* Set the source location of the && on the second 'if'.  */
	  if (rexpr_has_location (pred))
	    SET_EXPR_LOCATION (expr, rexpr_location (pred));
	  then_ = shortcut_cond_expr (expr);
	  then_se = then_ && TREE_SIDE_EFFECTS (then_);
	  pred = TREE_OPERAND (pred, 0);
	  expr = build3 (COND_EXPR, void_type_node, pred, then_, NULL_TREE);
	  SET_EXPR_LOCATION (expr, locus);
	}
    }

  if (!then_se)
    {
      /* If there is no 'then', turn
	   if (a || b); else d
	 into
	   if (a); else if (b); else d.  */
      while (TREE_CODE (pred) == TRUTH_ORIF_EXPR)
	{
	  /* Keep the original source location on the first 'if'.  */
	  location_t locus = EXPR_LOC_OR_LOC (expr, input_location);
	  TREE_OPERAND (expr, 0) = TREE_OPERAND (pred, 1);
	  /* Set the source location of the || on the second 'if'.  */
	  if (rexpr_has_location (pred))
	    SET_EXPR_LOCATION (expr, rexpr_location (pred));
	  else_ = shortcut_cond_expr (expr);
	  else_se = else_ && TREE_SIDE_EFFECTS (else_);
	  pred = TREE_OPERAND (pred, 0);
	  expr = build3 (COND_EXPR, void_type_node, pred, NULL_TREE, else_);
	  SET_EXPR_LOCATION (expr, locus);
	}
    }

  /* If we're done, great.  */
  if (TREE_CODE (pred) != TRUTH_ANDIF_EXPR
      && TREE_CODE (pred) != TRUTH_ORIF_EXPR)
    return expr;

  /* Otherwise we need to mess with gotos.  Change
       if (a) c; else d;
     to
       if (a); else goto no;
       c; goto end;
       no: d; end:
     and recursively gimplify the condition.  */

  true_label = false_label = end_label = NULL_TREE;

  /* If our arms just jump somewhere, hijack those labels so we don't
     generate jumps to jumps.  */

  if (tree then_goto = find_goto_label (then_))
    {
      true_label = GOTO_DESTINATION (then_goto);
      then_ = NULL;
      then_se = false;
    }

  if (tree else_goto = find_goto_label (else_))
    {
      false_label = GOTO_DESTINATION (else_goto);
      else_ = NULL;
      else_se = false;
    }

  /* If we aren't hijacking a label for the 'then' branch, it falls through.  */
  if (true_label)
    true_label_p = &true_label;
  else
    true_label_p = NULL;

  /* The 'else' branch also needs a label if it contains interesting code.  */
  if (false_label || else_se)
    false_label_p = &false_label;
  else
    false_label_p = NULL;

  /* If there was nothing else in our arms, just forward the label(s).  */
  if (!then_se && !else_se)
    return shortcut_cond_r (pred, true_label_p, false_label_p,
			    EXPR_LOC_OR_LOC (expr, input_location));

  /* If our last subexpression already has a terminal label, reuse it.  */
  if (else_se)
    t = expr_last (else_);
  else if (then_se)
    t = expr_last (then_);
  else
    t = NULL;
  if (t && TREE_CODE (t) == LABEL_EXPR)
    end_label = LABEL_EXPR_LABEL (t);

  /* If we don't care about jumping to the 'else' branch, jump to the end
     if the condition is false.  */
  if (!false_label_p)
    false_label_p = &end_label;

  /* We only want to emit these labels if we aren't hijacking them.  */
  emit_end = (end_label == NULL_TREE);
  emit_false = (false_label == NULL_TREE);

  /* We only emit the jump over the else clause if we have to--if the
     then clause may fall through.  Otherwise we can wind up with a
     useless jump and a useless label at the end of gimplified code,
     which will cause us to think that this conditional as a whole
     falls through even if it doesn't.  If we then inline a function
     which ends with such a condition, that can cause us to issue an
     inappropriate warning about control reaching the end of a
     non-void function.  */
  jump_over_else = block_may_fallthru (then_);

  pred = shortcut_cond_r (pred, true_label_p, false_label_p,
			  EXPR_LOC_OR_LOC (expr, input_location));

  expr = NULL;
  append_to_statement_list (pred, &expr);

  append_to_statement_list (then_, &expr);
  if (else_se)
    {
      if (jump_over_else)
	{
	  tree last = expr_last (expr);
	  t = build_and_jump (&end_label);
	  if (rexpr_has_location (last))
	    SET_EXPR_LOCATION (t, rexpr_location (last));
	  append_to_statement_list (t, &expr);
	}
      if (emit_false)
	{
	  t = build1 (LABEL_EXPR, void_type_node, false_label);
	  append_to_statement_list (t, &expr);
	}
      append_to_statement_list (else_, &expr);
    }
  if (emit_end && end_label)
    {
      t = build1 (LABEL_EXPR, void_type_node, end_label);
      append_to_statement_list (t, &expr);
    }

  return expr;
}

/* EXPR is used in a boolean context; make sure it has BOOLEAN_TYPE.  */

tree
gimple_boolify (tree expr)
{
  tree type = TREE_TYPE (expr);
  location_t loc = EXPR_LOCATION (expr);

  if (TREE_CODE (expr) == NE_EXPR
      && TREE_CODE (TREE_OPERAND (expr, 0)) == CALL_EXPR
      && integer_zerop (TREE_OPERAND (expr, 1)))
    {
      tree call = TREE_OPERAND (expr, 0);
      tree fn = get_callee_fndecl (call);

      /* For __builtin_expect ((long) (x), y) recurse into x as well
	 if x is truth_value_p.  */
      if (fn
	  && fndecl_built_in_p (fn, BUILT_IN_EXPECT)
	  && call_expr_nargs (call) == 2)
	{
	  tree arg = CALL_EXPR_ARG (call, 0);
	  if (arg)
	    {
	      if (TREE_CODE (arg) == NOP_EXPR
		  && TREE_TYPE (arg) == TREE_TYPE (call))
		arg = TREE_OPERAND (arg, 0);
	      if (truth_value_p (TREE_CODE (arg)))
		{
		  arg = gimple_boolify (arg);
		  CALL_EXPR_ARG (call, 0)
		    = fold_convert_loc (loc, TREE_TYPE (call), arg);
		}
	    }
	}
    }

  switch (TREE_CODE (expr))
    {
    case TRUTH_AND_EXPR:
    case TRUTH_OR_EXPR:
    case TRUTH_XOR_EXPR:
    case TRUTH_ANDIF_EXPR:
    case TRUTH_ORIF_EXPR:
      /* Also boolify the arguments of truth exprs.  */
      TREE_OPERAND (expr, 1) = gimple_boolify (TREE_OPERAND (expr, 1));
      /* FALLTHRU */

    case TRUTH_NOT_EXPR:
      TREE_OPERAND (expr, 0) = gimple_boolify (TREE_OPERAND (expr, 0));

      /* These expressions always produce boolean results.  */
      if (TREE_CODE (type) != BOOLEAN_TYPE)
	TREE_TYPE (expr) = boolean_type_node;
      return expr;

    case ANNOTATE_EXPR:
      switch ((enum annot_expr_kind) TREE_INT_CST_LOW (TREE_OPERAND (expr, 1)))
	{
	case annot_expr_ivdep_kind:
	case annot_expr_unroll_kind:
	case annot_expr_no_vector_kind:
	case annot_expr_vector_kind:
	case annot_expr_parallel_kind:
	  TREE_OPERAND (expr, 0) = gimple_boolify (TREE_OPERAND (expr, 0));
	  if (TREE_CODE (type) != BOOLEAN_TYPE)
	    TREE_TYPE (expr) = boolean_type_node;
	  return expr;
	default:
	  gcc_unreachable ();
	}

    default:
      if (COMPARISON_CLASS_P (expr))
	{
	  /* There expressions always prduce boolean results.  */
	  if (TREE_CODE (type) != BOOLEAN_TYPE)
	    TREE_TYPE (expr) = boolean_type_node;
	  return expr;
	}
      /* Other expressions that get here must have boolean values, but
	 might need to be converted to the appropriate mode.  */
      if (TREE_CODE (type) == BOOLEAN_TYPE)
	return expr;
      return fold_convert_loc (loc, boolean_type_node, expr);
    }
}

/* Given a conditional expression *EXPR_P without side effects, gimplify
   its operands.  New statements are inserted to PRE_P.  */

static enum gimplify_status
gimplify_pure_cond_expr (tree *expr_p, gimple_seq *pre_p)
{
  tree expr = *expr_p, cond;
  enum gimplify_status ret, tret;
  enum tree_code code;

  cond = gimple_boolify (COND_EXPR_COND (expr));

  /* We need to handle && and || specially, as their gimplification
     creates pure cond_expr, thus leading to an infinite cycle otherwise.  */
  code = TREE_CODE (cond);
  if (code == TRUTH_ANDIF_EXPR)
    TREE_SET_CODE (cond, TRUTH_AND_EXPR);
  else if (code == TRUTH_ORIF_EXPR)
    TREE_SET_CODE (cond, TRUTH_OR_EXPR);
  ret = gimplify_expr (&cond, pre_p, NULL, is_gimple_condexpr, fb_rvalue);
  COND_EXPR_COND (*expr_p) = cond;

  tret = gimplify_expr (&COND_EXPR_THEN (expr), pre_p, NULL,
				   is_gimple_val, fb_rvalue);
  ret = MIN (ret, tret);
  tret = gimplify_expr (&COND_EXPR_ELSE (expr), pre_p, NULL,
				   is_gimple_val, fb_rvalue);

  return MIN (ret, tret);
}

/* Return true if evaluating EXPR could trap.
   EXPR is GENERIC, while tree_could_trap_p can be called
   only on GIMPLE.  */

bool
generic_expr_could_trap_p (tree expr)
{
  unsigned i, n;

  if (!expr || is_gimple_val (expr))
    return false;

  if (!EXPR_P (expr) || tree_could_trap_p (expr))
    return true;

  n = TREE_OPERAND_LENGTH (expr);
  for (i = 0; i < n; i++)