gcc/cp/optimize.c

   1 /* Perform optimizations on tree structure.
   2
   3    Copyright (C) 1998, 1999 Free Software Foundation, Inc.
   4    Written by Mark Michell (mark@codesourcery.com).
   5
   6    This file is part of GNU CC.
   7
   8    GNU CC is free software; you can redistribute it and/or modify it
   9    under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2, or (at your option)
  11    any later version.
  12
  13    GNU CC is distributed in the hope that it will be useful, but
  14    WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16    General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with GNU CC; see the file COPYING.  If not, write to the Free
  20    Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  21    02111-1307, USA.  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "tree.h"
  26 #include "cp-tree.h"
  27 #include "rtl.h"
  28 #include "insn-config.h"
  29 #include "integrate.h"
  30 #include "varray.h"
  31
  32 /* To Do:
  33
  34    o In order to make inlining-on-trees work, we pessimized
  35      function-local static constants.  In particular, they are now
  36      always output, even when not addressed.  Fix this by treating
  37      function-local static constants just like global static
  38      constants; the back-end already knows not to output them if they
  39      are not needed.
  40
  41    o Provide heuristics to clamp inlining of recursive template
  42      calls?
  43
  44    o It looks like the return label is not being placed in the optimal
  45      place.  Shouldn't it come before the returned value?  */
  46
  47 /* Data required for function inlining.  */
  48
  49 typedef struct inline_data
  50 {
  51   /* A stack of the functions we are inlining.  For example, if we are
  52      compiling `f', which calls `g', which calls `h', and we are
  53      inlining the body of `h', the stack will contain, `h', followed
  54      by `g', followed by `f'.  */
  55   varray_type fns;
  56   /* The last SCOPE_STMT we have encountered.  */
  57   tree scope_stmt;
  58   /* The label to jump to when a return statement is encountered.  */
  59   tree ret_label;
  60   /* The map from local declarations in the inlined function to
  61      equivalents in the function into which it is being inlined.  */
  62   splay_tree decl_map;
  63   /* Nonzero if we are currently within the cleanup for a
  64      TARGET_EXPR.  */
  65   int in_target_cleanup_p;
  66 } inline_data;
  67
  68 /* Prototypes.  */
  69
  70 static tree initialize_inlined_parameters PROTO((inline_data *, tree));
  71 static tree declare_return_variable PROTO((inline_data *, tree *));
  72 static tree copy_body_r PROTO((tree *, int *, void *));
  73 static tree copy_body PROTO((inline_data *));
  74 static tree expand_call_inline PROTO((tree *, int *, void *));
  75 static void expand_calls_inline PROTO((tree *, inline_data *));
  76 static int inlinable_function_p PROTO((tree, inline_data *));
  77 static tree remap_decl PROTO((tree, inline_data *));
  78 static void remap_block PROTO((tree, tree, inline_data *));
  79 static void copy_scope_stmt PROTO((tree *, int *, inline_data *));
  80
  81 /* Remap DECL during the copying of the BLOCK tree for the function.
  82    DATA is really an `inline_data *'.  */
  83
  84 static tree
  85 remap_decl (decl, id)
  86      tree decl;
  87      inline_data *id;
  88 {
  89   splay_tree_node n;
  90   tree fn;
  91
  92   /* We only remap local variables in the current function.  */
  93   fn = VARRAY_TOP_TREE (id->fns);
  94   if (!nonstatic_local_decl_p (decl) || DECL_CONTEXT (decl) != fn)
  95     return NULL_TREE;
  96
  97   /* See if we have remapped this declaration.  */
  98   n = splay_tree_lookup (id->decl_map, (splay_tree_key) decl);
  99   /* If we didn't already have an equivalent for this declaration,
 100      create one now.  */
 101   if (!n)
 102     {
 103       tree t;
 104
 105       /* Make a copy of the variable or label.  */
 106       t = copy_decl_for_inlining (decl, fn,
 107                                   VARRAY_TREE (id->fns, 0));
 108       /* Remember it, so that if we encounter this local entity
 109          again we can reuse this copy.  */
 110       n = splay_tree_insert (id->decl_map,
 111                              (splay_tree_key) decl,
 112                              (splay_tree_value) t);
 113     }
 114
 115   return (tree) n->value;
 116 }
 117
 118 /* Copy the SCOPE_STMT_BLOCK associated with SCOPE_STMT to contain
 119    remapped versions of the variables therein.  And hook the new block
 120    into the block-tree.  If non-NULL, the DECLS are declarations to
 121    add to use instead of the BLOCK_VARS in the old block.  */
 122
 123 static void
 124 remap_block (scope_stmt, decls, id)
 125      tree scope_stmt;
 126      tree decls;
 127      inline_data *id;
 128 {
 129   /* We cannot do this in the cleanup for a TARGET_EXPR since we do
 130      not know whether or not expand_expr will actually write out the
 131      code we put there.  If it does not, then we'll have more BLOCKs
 132      than block-notes, and things will go awry.  At some point, we
 133      should make the back-end handle BLOCK notes in a tidier way,
 134      without requiring a strict correspondence to the block-tree; then
 135      this check can go.  */
 136   if (id->in_target_cleanup_p)
 137     {
 138       SCOPE_STMT_BLOCK (scope_stmt) = NULL_TREE;
 139       return;
 140     }
 141
 142   /* If this is the beginning of a scope, remap the associated BLOCK.  */
 143   if (SCOPE_BEGIN_P (scope_stmt) && SCOPE_STMT_BLOCK (scope_stmt))
 144     {
 145       tree old_block;
 146       tree new_block;
 147       tree old_var;
 148
 149       /* Make the new block.  */
 150       old_block = SCOPE_STMT_BLOCK (scope_stmt);
 151       new_block = make_node (BLOCK);
 152       TREE_USED (new_block) = TREE_USED (old_block);
 153       BLOCK_ABSTRACT_ORIGIN (new_block) = old_block;
 154       SCOPE_STMT_BLOCK (scope_stmt) = new_block;
 155
 156       /* Remap its variables.  */
 157       for (old_var = decls ? decls : BLOCK_VARS (old_block);
 158            old_var;
 159            old_var = TREE_CHAIN (old_var))
 160         {
 161           tree new_var;
 162
 163           /* Remap the variable.  */
 164           new_var = remap_decl (old_var, id);
 165           if (!new_var)
 166             /* We didn't remap this variable, so we can't mess with
 167                its TREE_CHAIN.  */
 168             ;
 169           else
 170             {
 171               TREE_CHAIN (new_var) = BLOCK_VARS (new_block);
 172               BLOCK_VARS (new_block) = new_var;
 173             }
 174         }
 175       /* We put the BLOCK_VARS in reverse order; fix that now.  */
 176       BLOCK_VARS (new_block) = nreverse (BLOCK_VARS (new_block));
 177       /* Graft the new block into the tree.  */
 178       insert_block_after_note (new_block,
 179                                (id->scope_stmt
 180                                 ? SCOPE_STMT_BLOCK (id->scope_stmt)
 181                                 : NULL_TREE),
 182                                (id->scope_stmt
 183                                 ? SCOPE_BEGIN_P (id->scope_stmt) : 1),
 184                                VARRAY_TREE (id->fns, 0));
 185       /* Remember that this is now the last scope statement with
 186          an associated block.  */
 187       id->scope_stmt = scope_stmt;
 188       /* Remember the remapped block.  */
 189       splay_tree_insert (id->decl_map,
 190                          (splay_tree_key) old_block,
 191                          (splay_tree_value) new_block);
 192     }
 193   /* If this is the end of a scope, set the SCOPE_STMT_BLOCK to be the
 194      remapped block.  */
 195   else if (SCOPE_END_P (scope_stmt) && SCOPE_STMT_BLOCK (scope_stmt))
 196     {
 197       splay_tree_node n;
 198
 199       /* Find this block in the table of remapped things.  */
 200       n = splay_tree_lookup (id->decl_map,
 201                              (splay_tree_key) SCOPE_STMT_BLOCK (scope_stmt));
 202       my_friendly_assert (n != NULL, 19991203);
 203       SCOPE_STMT_BLOCK (scope_stmt) = (tree) n->value;
 204
 205       /* Remember that this is now the last scope statement with an
 206          associated block.  */
 207       id->scope_stmt = scope_stmt;
 208     }
 209 }
 210
 211 /* Copy the SCOPE_STMT pointed to by TP.  */
 212
 213 static void
 214 copy_scope_stmt (tp, walk_subtrees, id)
 215      tree *tp;
 216      int *walk_subtrees;
 217      inline_data *id;
 218 {
 219   tree block;
 220
 221   /* Remember whether or not this statement was nullified.  When
 222      making a copy, copy_tree_r always sets SCOPE_NULLIFIED_P (and
 223      doesn't copy the SCOPE_STMT_BLOCK) to free callers from having to
 224      deal with copying BLOCKs if they do not wish to do so.  */
 225   block = SCOPE_STMT_BLOCK (*tp);
 226   /* Copy (and replace) the statement.  */
 227   copy_tree_r (tp, walk_subtrees, NULL);
 228   /* Restore the SCOPE_STMT_BLOCK.  */
 229   SCOPE_STMT_BLOCK (*tp) = block;
 230
 231   /* Remap the associated block.  */
 232   remap_block (*tp, NULL_TREE, id);
 233 }
 234
 235 /* Called from copy_body via walk_tree.  DATA is really an
 236    `inline_data *'.  */
 237
 238 static tree
 239 copy_body_r (tp, walk_subtrees, data)
 240      tree *tp;
 241      int *walk_subtrees;
 242      void *data;
 243 {
 244   inline_data* id;
 245   tree fn;
 246
 247   /* Set up.  */
 248   id = (inline_data *) data;
 249   fn = VARRAY_TOP_TREE (id->fns);
 250
 251   /* All automatic variables should have a DECL_CONTEXT indicating
 252      what function they come from.  */
 253   if ((TREE_CODE (*tp) == VAR_DECL || TREE_CODE (*tp) == LABEL_DECL)
 254       && DECL_NAMESPACE_SCOPE_P (*tp))
 255     my_friendly_assert (DECL_EXTERNAL (*tp) || TREE_STATIC (*tp),
 256                         19991113);
 257
 258   /* If this is a RETURN_STMT, change it into an EXPR_STMT and a
 259      GOTO_STMT with the RET_LABEL as its target.  */
 260   if (TREE_CODE (*tp) == RETURN_STMT)
 261     {
 262       tree return_stmt = *tp;
 263       tree goto_stmt;
 264
 265       /* Build the GOTO_STMT.  */
 266       goto_stmt = build_min_nt (GOTO_STMT, id->ret_label);
 267       TREE_CHAIN (goto_stmt) = TREE_CHAIN (return_stmt);
 268
 269       /* If we're returning something, just turn that into an
 270          assignment into the equivalent of the original
 271          RESULT_DECL.  */
 272       if (RETURN_EXPR (return_stmt))
 273         {
 274           *tp = build_min_nt (EXPR_STMT,
 275                               RETURN_EXPR (return_stmt));
 276           /* And then jump to the end of the function.  */
 277           TREE_CHAIN (*tp) = goto_stmt;
 278         }
 279       /* If we're not returning anything just do the jump.  */
 280       else
 281         *tp = goto_stmt;
 282     }
 283   /* Local variables and labels need to be replaced by equivalent
 284      variables.  We don't want to copy static variables; there's only
 285      one of those, no matter how many times we inline the containing
 286      function.  */
 287   else if (nonstatic_local_decl_p (*tp) && DECL_CONTEXT (*tp) == fn)
 288     {
 289       tree new_decl;
 290
 291       /* Remap the declaration.  */
 292       new_decl = remap_decl (*tp, id);
 293       my_friendly_assert (new_decl != NULL_TREE, 19991203);
 294       /* Replace this variable with the copy.  */
 295       *tp = new_decl;
 296     }
 297   else if (TREE_CODE (*tp) == SAVE_EXPR)
 298     remap_save_expr (tp, id->decl_map, VARRAY_TREE (id->fns, 0));
 299   else if (TREE_CODE (*tp) == UNSAVE_EXPR)
 300     my_friendly_abort (19991113);
 301   /* For a SCOPE_STMT, we must copy the associated block so that we
 302      can write out debugging information for the inlined variables.  */
 303   else if (TREE_CODE (*tp) == SCOPE_STMT && !id->in_target_cleanup_p)
 304     copy_scope_stmt (tp, walk_subtrees, id);
 305   /* Otherwise, just copy the node.  Note that copy_tree_r already
 306      knows not to copy VAR_DECLs, etc., so this is safe.  */
 307   else
 308     {
 309       copy_tree_r (tp, walk_subtrees, NULL);
 310
 311       /* The copied TARGET_EXPR has never been expanded, even if the
 312          original node was expanded already.  */
 313       if (TREE_CODE (*tp) == TARGET_EXPR && TREE_OPERAND (*tp, 3))
 314         TREE_OPERAND (*tp, 1) = TREE_OPERAND (*tp, 3);
 315       /* Similarly, if we're copying a CALL_EXPR, the RTL for the
 316          result is no longer valid.  */
 317       else if (TREE_CODE (*tp) == CALL_EXPR)
 318         CALL_EXPR_RTL (*tp) = NULL_RTX;
 319     }
 320
 321   /* Keep iterating.  */
 322   return NULL_TREE;
 323 }
 324
 325 /* Make a copy of the body of FN so that it can be inserted inline in
 326    another function.  */
 327
 328 static tree
 329 copy_body (id)
 330      inline_data *id;
 331 {
 332   tree body;
 333
 334   body = DECL_SAVED_TREE (VARRAY_TOP_TREE (id->fns));
 335   walk_tree (&body, copy_body_r, id);
 336
 337   return body;
 338 }
 339
 340 /* Generate code to initialize the parameters of the function at the
 341    top of the stack in ID from the ARGS (presented as a TREE_LIST).  */
 342
 343 static tree
 344 initialize_inlined_parameters (id, args)
 345      inline_data *id;
 346      tree args;
 347 {
 348   tree fn;
 349   tree init_stmts;
 350   tree parms;
 351   tree a;
 352   tree p;
 353
 354   /* Figure out what the parameters are.  */
 355   fn = VARRAY_TOP_TREE (id->fns);
 356   parms = DECL_ARGUMENTS (fn);
 357
 358   /* Start with no initializations whatsoever.  */
 359   init_stmts = NULL_TREE;
 360
 361   /* Loop through the parameter declarations, replacing each with an
 362      equivalent VAR_DECL, appropriately initialized.  */
 363   for (p = parms, a = args; p; a = TREE_CHAIN (a), p = TREE_CHAIN (p))
 364     {
 365       tree init_stmt;
 366       tree var;
 367
 368       /* Make an equivalent VAR_DECL.  */
 369       var = copy_decl_for_inlining (p, fn, VARRAY_TREE (id->fns, 0));
 370       /* Register the VAR_DECL as the equivalent for the PARM_DECL;
 371          that way, when the PARM_DECL is encountered, it will be
 372          automatically replaced by the VAR_DECL.  */
 373       splay_tree_insert (id->decl_map,
 374                          (splay_tree_key) p,
 375                          (splay_tree_value) var);
 376       /* Initialize this VAR_DECL from the equivalent argument.  If
 377          the argument is an object, created via a constructor or copy,
 378          this will not result in an extra copy: the TARGET_EXPR
 379          representing the argument will be bound to VAR, and the
 380          object will be constructed in VAR.  */
 381       init_stmt = build_min_nt (EXPR_STMT,
 382                                 build (INIT_EXPR, TREE_TYPE (p),
 383                                        var, TREE_VALUE (a)));
 384       /* Declare this new variable.  Note that we do this *after* the
 385          initialization because we are going to reverse all the
 386          initialization statements below.  */
 387       TREE_CHAIN (init_stmt) = build_min_nt (DECL_STMT, var);
 388       /* Add this initialization to the list.  */
 389       TREE_CHAIN (TREE_CHAIN (init_stmt)) = init_stmts;
 390       init_stmts = init_stmt;
 391     }
 392
 393   /* The initialization statements have been built up in reverse
 394      order.  Straighten them out now.  */
 395   return nreverse (init_stmts);
 396 }
 397
 398 /* Declare a return variable to replace the RESULT_DECL for the
 399    function we are calling.  An appropriate DECL_STMT is returned.
 400    The USE_STMT is filled in to contain a use of the declaration to
 401    indicate the return value of the function.  */
 402
 403 static tree
 404 declare_return_variable (id, use_stmt)
 405      struct inline_data *id;
 406      tree *use_stmt;
 407 {
 408   tree fn = VARRAY_TOP_TREE (id->fns);
 409   tree result = DECL_RESULT (fn);
 410   tree var;
 411
 412   /* We don't need to do anything for functions that don't return
 413      anything.  */
 414   if (!result || same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (result)),
 415                               void_type_node))
 416     {
 417       *use_stmt = NULL_TREE;
 418       return NULL_TREE;
 419     }
 420
 421   /* Make an appropriate copy.  */
 422   var = copy_decl_for_inlining (result, fn, VARRAY_TREE (id->fns, 0));
 423   /* Register the VAR_DECL as the equivalent for the RESULT_DECL; that
 424      way, when the RESULT_DECL is encountered, it will be
 425      automatically replaced by the VAR_DECL.  */
 426   splay_tree_insert (id->decl_map,
 427                      (splay_tree_key) result,
 428                      (splay_tree_value) var);
 429
 430   /* Build the USE_STMT.  */
 431   *use_stmt = build_min_nt (EXPR_STMT, var);
 432
 433   /* Build the declaration statement.  */
 434   return build_min_nt (DECL_STMT, var);
 435 }
 436
 437 /* Returns non-zero if FN is a function that can be inlined.  */
 438
 439 static int
 440 inlinable_function_p (fn, id)
 441      tree fn;
 442      inline_data *id;
 443 {
 444   int inlinable;
 445
 446   /* If we've already decided this function shouldn't be inlined,
 447      there's no need to check again.  */
 448   if (DECL_UNINLINABLE (fn))
 449     return 0;
 450
 451   /* Assume it is not inlinable.  */
 452   inlinable = 0;
 453
 454   /* If we're not inlining things, then nothing is inlinable.  */
 455   if (!flag_inline_trees)
 456     ;
 457   /* If the function was not declared `inline', then we don't inline
 458      it.  */
 459   else if (!DECL_INLINE (fn))
 460     ;
 461   /* If we don't have the function body available, we can't inline
 462      it.  */
 463   else if (!DECL_SAVED_TREE (fn))
 464     ;
 465   /* We can't inline varargs functions.  */
 466   else if (varargs_function_p (fn))
 467     ;
 468   /* All is well.  We can inline this function.  Traditionally, GCC
 469      has refused to inline functions using setjmp or alloca, or
 470      functions whose values are returned in a PARALLEL, and a few
 471      other such obscure conditions.  We are not equally constrained at
 472      the tree level.  */
 473   else
 474     inlinable = 1;
 475
 476   /* Squirrel away the result so that we don't have to check again.  */
 477   DECL_UNINLINABLE (fn) = !inlinable;
 478
 479   /* Don't do recursive inlining, either.  We don't record this in
 480      DECL_UNLINABLE; we may be able to inline this function later.  */
 481   if (inlinable)
 482     {
 483       size_t i;
 484
 485       for (i = 0; i < id->fns->elements_used; ++i)
 486         if (VARRAY_TREE (id->fns, i) == fn)
 487           inlinable = 0;
 488     }
 489
 490   /* We can inline a template instantiation only if its fully
 491      instantiated.  */
 492   if (inlinable
 493       && DECL_TEMPLATE_INFO (fn)
 494       && TI_PENDING_TEMPLATE_FLAG (DECL_TEMPLATE_INFO (fn)))
 495     {
 496       fn = instantiate_decl (fn);
 497       inlinable = !TI_PENDING_TEMPLATE_FLAG (DECL_TEMPLATE_INFO (fn));
 498     }
 499
 500   /* Return the result.  */
 501   return inlinable;
 502 }
 503
 504 /* If *TP is CALL_EXPR, replace it with its inline expansion.  */
 505
 506 static tree
 507 expand_call_inline (tp, walk_subtrees, data)
 508      tree *tp;
 509      int *walk_subtrees;
 510      void *data;
 511 {
 512   inline_data *id;
 513   tree t;
 514   tree expr;
 515   tree chain;
 516   tree fn;
 517   tree scope_stmt;
 518   tree use_stmt;
 519   splay_tree st;
 520
 521   /* See what we've got.  */
 522   id = (inline_data *) data;
 523   t = *tp;
 524
 525   /* Keep track of the last SCOPE_STMT we've seen.  */
 526   if (TREE_CODE (t) == SCOPE_STMT)
 527     {
 528       if (SCOPE_STMT_BLOCK (t) && !id->in_target_cleanup_p)
 529         id->scope_stmt = t;
 530       return NULL_TREE;
 531     }
 532
 533   /* Recurse, but letting recursive invocations know that we are
 534      inside the body of a TARGET_EXPR.  */
 535   if (TREE_CODE (*tp) == TARGET_EXPR)
 536     {
 537       int i;
 538
 539       /* We're walking our own subtrees.  */
 540       *walk_subtrees = 0;
 541
 542       /* Actually walk over them.  This loop is the body of
 543          walk_trees, omitting the case where the TARGET_EXPR
 544          itself is handled.  */
 545       for (i = first_rtl_op (TARGET_EXPR) - 1; i >= 0; --i)
 546         {
 547           if (i == 2)
 548             ++id->in_target_cleanup_p;
 549           walk_tree (&TREE_OPERAND (*tp, i), expand_call_inline, data);
 550           if (i == 2)
 551             --id->in_target_cleanup_p;
 552         }
 553
 554       return NULL_TREE;
 555     }
 556
 557   /* From here on, we're only interested in CALL_EXPRs.  */
 558   if (TREE_CODE (t) != CALL_EXPR)
 559     return NULL_TREE;
 560
 561   /* First, see if we can figure out what function is being called.
 562      If we cannot, then there is no hope of inlining the function.  */
 563   fn = get_callee_fndecl (t);
 564   if (!fn)
 565     return NULL_TREE;
 566
 567   /* Don't try to inline functions that are not well-suited to
 568      inlining.  */
 569   if (!inlinable_function_p (fn, id))
 570     return NULL_TREE;
 571
 572   /* Return statements in the function body will be replaced by jumps
 573      to the RET_LABEL.  */
 574   id->ret_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
 575   DECL_CONTEXT (id->ret_label) = VARRAY_TREE (id->fns, 0);
 576
 577   /* Build a statement-expression containing code to initialize the
 578      arguments, the actual inline expansion of the body, and a label
 579      for the return statements within the function to jump to.  The
 580      type of the statement expression is the return type of the
 581      function call.  */
 582   expr = build_min (STMT_EXPR, TREE_TYPE (TREE_TYPE (fn)), NULL_TREE);
 583
 584   /* Record the function we are about to inline so that we can avoid
 585      recursing into it.  */
 586   VARRAY_PUSH_TREE (id->fns, fn);
 587
 588   /* Local declarations will be replaced by their equivalents in this
 589      map.  */
 590   st = id->decl_map;
 591   id->decl_map = splay_tree_new (splay_tree_compare_pointers,
 592                                  NULL, NULL);
 593
 594   /* Initialize the parameters.  */
 595   STMT_EXPR_STMT (expr)
 596     = initialize_inlined_parameters (id, TREE_OPERAND (t, 1));
 597
 598   /* Create a block to put the parameters in.  We have to do this
 599      after the parameters have been remapped because remapping
 600      parameters is different from remapping ordinary variables.  */
 601   scope_stmt = build_min_nt (SCOPE_STMT, DECL_INITIAL (fn));
 602   SCOPE_BEGIN_P (scope_stmt) = 1;
 603   SCOPE_NO_CLEANUPS_P (scope_stmt) = 1;
 604   remap_block (scope_stmt, DECL_ARGUMENTS (fn), id);
 605   TREE_CHAIN (scope_stmt) = STMT_EXPR_STMT (expr);
 606   STMT_EXPR_STMT (expr) = scope_stmt;
 607   id->scope_stmt = scope_stmt;
 608
 609   /* Declare the return variable for the function.  */
 610   STMT_EXPR_STMT (expr)
 611     = chainon (STMT_EXPR_STMT (expr),
 612                declare_return_variable (id, &use_stmt));
 613
 614   /* After we've initialized the parameters, we insert the body of the
 615      function itself.  */
 616   STMT_EXPR_STMT (expr)
 617     = chainon (STMT_EXPR_STMT (expr), copy_body (id));
 618
 619   /* Close the block for the parameters.  */
 620   scope_stmt = build_min_nt (SCOPE_STMT, DECL_INITIAL (fn));
 621   SCOPE_NO_CLEANUPS_P (scope_stmt) = 1;
 622   my_friendly_assert (DECL_INITIAL (fn)
 623                       && TREE_CODE (DECL_INITIAL (fn)) == BLOCK,
 624                       19991203);
 625   remap_block (scope_stmt, NULL_TREE, id);
 626   STMT_EXPR_STMT (expr)
 627     = chainon (STMT_EXPR_STMT (expr), scope_stmt);
 628
 629   /* Finally, mention the returned value so that the value of the
 630      statement-expression is the returned value of the function.  */
 631   STMT_EXPR_STMT (expr) = chainon (STMT_EXPR_STMT (expr), use_stmt);
 632
 633   /* Clean up.  */
 634   splay_tree_delete (id->decl_map);
 635   id->decl_map = st;
 636
 637   /* After the body of the function comes the RET_LABEL.  */
 638   STMT_EXPR_STMT (expr)
 639     = chainon (STMT_EXPR_STMT (expr),
 640                build_min_nt (LABEL_STMT, id->ret_label));
 641
 642   /* The new expression has side-effects if the old one did.  */
 643   TREE_SIDE_EFFECTS (expr) = TREE_SIDE_EFFECTS (t);
 644   /* If the value of the new expression is ignored, that's OK.  We
 645      don't warn about this for CALL_EXPRs, so we shouldn't warn about
 646      the equivalent inlined version either.  */
 647   TREE_USED (expr) = 1;
 648
 649   /* Replace the call by the inlined body.  */
 650   chain = TREE_CHAIN (*tp);
 651   *tp = expr;
 652   TREE_CHAIN (expr) = chain;
 653
 654   /* Recurse into the body of the just inlined function.  */
 655   expand_calls_inline (tp, id);
 656   VARRAY_POP (id->fns);
 657
 658   /* Don't walk into subtrees.  We've already handled them above.  */
 659   *walk_subtrees = 0;
 660
 661   /* Keep iterating.  */
 662   return NULL_TREE;
 663 }
 664
 665 /* Walk over the entire tree *TP, replacing CALL_EXPRs with inline
 666    expansions as appropriate.  */
 667
 668 static void
 669 expand_calls_inline (tp, id)
 670      tree *tp;
 671      inline_data *id;
 672 {
 673   /* Search through *TP, replacing all calls to inline functions by
 674      appropriate equivalents.  */
 675   walk_tree (tp, expand_call_inline, id);
 676 }
 677
 678 /* Optimize the body of FN.  */
 679
 680 void
 681 optimize_function (fn)
 682      tree fn;
 683 {
 684   /* Expand calls to inline functions.  */
 685   if (flag_inline_trees)
 686     {
 687       inline_data id;
 688       tree prev_fn;
 689       struct saved_scope *s;
 690
 691       /* Clear out ID.  */
 692       bzero (&id, sizeof (id));
 693
 694       /* Don't allow recursion into FN.  */
 695       VARRAY_TREE_INIT (id.fns, 32, "fns");
 696       VARRAY_PUSH_TREE (id.fns, fn);
 697       /* Or any functions that aren't finished yet.  */
 698       prev_fn = NULL_TREE;
 699       if (current_function_decl)
 700         {
 701           VARRAY_PUSH_TREE (id.fns, current_function_decl);
 702           prev_fn = current_function_decl;
 703         }
 704       for (s = scope_chain; s; s = s->prev)
 705         if (s->function_decl && s->function_decl != prev_fn)
 706           {
 707             VARRAY_PUSH_TREE (id.fns, s->function_decl);
 708             prev_fn = s->function_decl;
 709           }
 710       /* Replace all calls to inline functions with the bodies of those
 711          functions.  */
 712       expand_calls_inline (&DECL_SAVED_TREE (fn), &id);
 713
 714       /* Clean up.  */
 715       VARRAY_FREE (id.fns);
 716     }
 717 }