gcc/function-tests.c

   1 /* Unit tests for function-handling.
   2    Copyright (C) 2015-2021 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "tm.h"
  24 #include "opts.h"
  25 #include "hash-set.h"
  26 #include "fixed-value.h"
  27 #include "alias.h"
  28 #include "flags.h"
  29 #include "symtab.h"
  30 #include "tree-core.h"
  31 #include "stor-layout.h"
  32 #include "tree.h"
  33 #include "stringpool.h"
  34 #include "stor-layout.h"
  35 #include "rtl.h"
  36 #include "predict.h"
  37 #include "vec.h"
  38 #include "hashtab.h"
  39 #include "hash-set.h"
  40 #include "hard-reg-set.h"
  41 #include "input.h"
  42 #include "function.h"
  43 #include "dominance.h"
  44 #include "cfg.h"
  45 #include "cfganal.h"
  46 #include "basic-block.h"
  47 #include "tree-ssa-alias.h"
  48 #include "internal-fn.h"
  49 #include "gimple-fold.h"
  50 #include "gimple-expr.h"
  51 #include "toplev.h"
  52 #include "print-tree.h"
  53 #include "tree-iterator.h"
  54 #include "gimplify.h"
  55 #include "tree-cfg.h"
  56 #include "basic-block.h"
  57 #include "alias.h"
  58 #include "symtab.h"
  59 #include "inchash.h"
  60 #include "tree.h"
  61 #include "fold-const.h"
  62 #include "stor-layout.h"
  63 #include "stmt.h"
  64 #include "hash-table.h"
  65 #include "tree-ssa-alias.h"
  66 #include "internal-fn.h"
  67 #include "gimple-expr.h"
  68 #include "is-a.h"
  69 #include "gimple.h"
  70 #include "tree-pass.h"
  71 #include "context.h"
  72 #include "hash-map.h"
  73 #include "plugin-api.h"
  74 #include "ipa-ref.h"
  75 #include "cgraph.h"
  76 #include "selftest.h"
  77 #include "print-rtl.h"
  78
  79 #if CHECKING_P
  80
  81 namespace selftest {
  82
  83 /* Helper function for selftests of function-creation.  */
  84
  85 tree
  86 make_fndecl (tree return_type,
  87              const char *name,
  88              vec <tree> &param_types,
  89              bool is_variadic)
  90 {
  91   tree fn_type;
  92   if (is_variadic)
  93     fn_type = build_varargs_function_type_array (return_type,
  94                                                  param_types.length (),
  95                                                  param_types.address ());
  96   else
  97     fn_type = build_function_type_array (return_type,
  98                                          param_types.length (),
  99                                          param_types.address ());
 100   /* FIXME: this uses input_location: */
 101   tree fndecl = build_fn_decl (name, fn_type);
 102
 103   return fndecl;
 104 }
 105
 106 /* Verify creating a function declaration equivalent to the following
 107      int test_fndecl_int_void (void);
 108    C declaration.  */
 109
 110 static void
 111 test_fndecl_int_void ()
 112 {
 113   auto_vec <tree> param_types;
 114   const char *name = "test_fndecl_int_void";
 115   tree fndecl = make_fndecl (integer_type_node,
 116                              name,
 117                              param_types);
 118   ASSERT_TRUE (fndecl != NULL);
 119
 120   /* Verify name of decl.  */
 121   tree declname = DECL_NAME (fndecl);
 122   ASSERT_TRUE (declname != NULL);
 123   ASSERT_EQ (IDENTIFIER_NODE, TREE_CODE (declname));
 124   /* We expect it to use a *copy* of the string we passed in.  */
 125   const char *identifier_ptr = IDENTIFIER_POINTER (declname);
 126   ASSERT_NE (name, identifier_ptr);
 127   ASSERT_EQ (0, strcmp ("test_fndecl_int_void", identifier_ptr));
 128
 129   /* Verify type of fndecl.  */
 130   ASSERT_EQ (FUNCTION_DECL, TREE_CODE (fndecl));
 131   tree fntype = TREE_TYPE (fndecl);
 132   ASSERT_EQ (FUNCTION_TYPE, TREE_CODE (fntype));
 133
 134   /* Verify return type.  */
 135   ASSERT_EQ (integer_type_node, TREE_TYPE (fntype));
 136
 137   /* Verify "void" args.  */
 138   tree argtypes = TYPE_ARG_TYPES (fntype);
 139   ASSERT_EQ (TREE_LIST, TREE_CODE (argtypes));
 140   ASSERT_EQ (void_type_node, TREE_VALUE (argtypes));
 141   ASSERT_EQ (NULL, TREE_CHAIN (argtypes));
 142 }
 143
 144 /* Verify creating a function declaration equivalent to the following
 145      float test_fndecl_float_intchar (int, char);
 146    C declaration.  */
 147
 148 static void
 149 test_fndecl_float_intchar ()
 150 {
 151   auto_vec <tree> param_types;
 152   param_types.safe_push (integer_type_node);
 153   param_types.safe_push (char_type_node);
 154   const char *name = "test_fndecl_float_intchar";
 155   tree fndecl = make_fndecl (float_type_node,
 156                              name,
 157                              param_types);
 158   ASSERT_TRUE (fndecl != NULL);
 159
 160   /* Verify name of decl.  */
 161   tree declname = DECL_NAME (fndecl);
 162   ASSERT_TRUE (declname != NULL);
 163   ASSERT_EQ (IDENTIFIER_NODE, TREE_CODE (declname));
 164   /* We expect it to use a *copy* of the string we passed in.  */
 165   const char *identifier_ptr = IDENTIFIER_POINTER (declname);
 166   ASSERT_NE (name, identifier_ptr);
 167   ASSERT_EQ (0, strcmp (name, identifier_ptr));
 168
 169   /* Verify type of fndecl.  */
 170   ASSERT_EQ (FUNCTION_DECL, TREE_CODE (fndecl));
 171   tree fntype = TREE_TYPE (fndecl);
 172   ASSERT_EQ (FUNCTION_TYPE, TREE_CODE (fntype));
 173
 174   /* Verify return type.  */
 175   ASSERT_EQ (float_type_node, TREE_TYPE (fntype));
 176
 177   /* Verify "(int, char)" args.  */
 178   tree arg0 = TYPE_ARG_TYPES (fntype);
 179   ASSERT_EQ (TREE_LIST, TREE_CODE (arg0));
 180   ASSERT_EQ (integer_type_node, TREE_VALUE (arg0));
 181   tree arg1 = TREE_CHAIN (arg0);
 182   ASSERT_TRUE (arg1 != NULL);
 183   ASSERT_EQ (TREE_LIST, TREE_CODE (arg1));
 184   ASSERT_EQ (char_type_node, TREE_VALUE (arg1));
 185   tree argterm = TREE_CHAIN (arg1);
 186   ASSERT_TRUE (argterm != NULL);
 187   ASSERT_EQ (TREE_LIST, TREE_CODE (argterm));
 188   ASSERT_EQ (void_type_node, TREE_VALUE (argterm));
 189   ASSERT_EQ (NULL, TREE_CHAIN (argterm));
 190 }
 191
 192 /* The test cases using these helper functions take a trivial function:
 193
 194      int test_fn (void) { return 42; }
 195
 196    and test various conversions done to it:
 197
 198    - gimplification
 199    - construction of the CFG
 200    - conversion to SSA form
 201    - expansion to RTL form
 202
 203    In avoid having one overlong test case, this is broken
 204    up into separate test cases for each stage, with helper functions
 205    to minimize code duplication.
 206
 207    Another approach would be to attempt to directly construct a function
 208    in the appropriate representation at each stage, though presumably
 209    that would exhibit different kinds of failure compared to this
 210    approach.  */
 211
 212 /* Construct this function:
 213    int test_fn (void) { return 42; }
 214    in generic tree form.  Return the fndecl.  */
 215
 216 static tree
 217 build_trivial_generic_function ()
 218 {
 219   auto_vec <tree> param_types;
 220   tree fndecl = make_fndecl (integer_type_node,
 221                              "test_fn",
 222                              param_types);
 223   ASSERT_TRUE (fndecl != NULL);
 224
 225   /* Populate the function.  */
 226   tree retval = build_decl (UNKNOWN_LOCATION, RESULT_DECL,
 227                             NULL_TREE, integer_type_node);
 228   DECL_ARTIFICIAL (retval) = 1;
 229   DECL_IGNORED_P (retval) = 1;
 230   DECL_RESULT (fndecl) = retval;
 231
 232   /* Create a BIND_EXPR, and within it, a statement list.  */
 233   tree stmt_list = alloc_stmt_list ();
 234   tree_stmt_iterator stmt_iter = tsi_start (stmt_list);
 235   tree block = make_node (BLOCK);
 236   tree bind_expr
 237     = build3 (BIND_EXPR, void_type_node, NULL, stmt_list, block);
 238
 239   tree modify_retval = build2 (MODIFY_EXPR,
 240                                integer_type_node,
 241                                retval,
 242                                build_int_cst (integer_type_node, 42));
 243   tree return_stmt = build1 (RETURN_EXPR,
 244                              integer_type_node,
 245                              modify_retval);
 246   tsi_link_after (&stmt_iter, return_stmt, TSI_CONTINUE_LINKING);
 247
 248   DECL_INITIAL (fndecl) = block;
 249   BLOCK_SUPERCONTEXT (block) = fndecl;
 250
 251   /* how to add to function? the following appears to be how to
 252      set the body of a fndecl: */
 253   DECL_SAVED_TREE(fndecl) = bind_expr;
 254
 255   /* Ensure that locals appear in the debuginfo.  */
 256   BLOCK_VARS (block) = BIND_EXPR_VARS (bind_expr);
 257
 258   return fndecl;
 259 }
 260
 261 /* Construct this function:
 262      int test_fn (void) { return 42; }
 263    in "high gimple" form.  Return the fndecl.  */
 264
 265 static tree
 266 build_trivial_high_gimple_function ()
 267 {
 268   /* Construct a trivial function, and gimplify it: */
 269   tree fndecl = build_trivial_generic_function ();
 270   gimplify_function_tree (fndecl);
 271   return fndecl;
 272 }
 273
 274 /* Build a CFG for a function in gimple form.  */
 275
 276 static void
 277 build_cfg (tree fndecl)
 278 {
 279   function *fun = DECL_STRUCT_FUNCTION (fndecl);
 280   ASSERT_TRUE (fun != NULL);
 281   ASSERT_EQ (fndecl, fun->decl);
 282
 283   /* We first have to lower control flow; for our trivial test function
 284      this gives us:
 285          test_fn ()
 286          {
 287            D.56 = 42;
 288            goto <D.57>;
 289            <D.57>:
 290            return D.56;
 291          }
 292   */
 293   gimple_opt_pass *lower_cf_pass = make_pass_lower_cf (g);
 294   push_cfun (fun);
 295   lower_cf_pass->execute (fun);
 296   pop_cfun ();
 297   delete lower_cf_pass;
 298
 299   /* We can now convert to CFG form; for our trivial test function this
 300      gives us:
 301          test_fn ()
 302          {
 303            <bb 2>:
 304            D.56 = 42;
 305            return D.56;
 306          }
 307   */
 308   gimple_opt_pass *build_cfg_pass = make_pass_build_cfg (g);
 309   push_cfun (fun);
 310   build_cfg_pass->execute (fun);
 311   pop_cfun ();
 312   delete build_cfg_pass;
 313 }
 314
 315 /* Convert a gimple+CFG function to SSA form.  */
 316
 317 static void
 318 convert_to_ssa (tree fndecl)
 319 {
 320   function *fun = DECL_STRUCT_FUNCTION (fndecl);
 321   ASSERT_TRUE (fun != NULL);
 322   ASSERT_EQ (fndecl, fun->decl);
 323
 324   gimple_opt_pass *build_ssa_pass = make_pass_build_ssa (g);
 325   push_cfun (fun);
 326   build_ssa_pass->execute (fun);
 327   pop_cfun ();
 328   delete build_ssa_pass;
 329 }
 330
 331 /* Assuming we have a simple 3-block CFG like this:
 332      [ENTRY] -> [block2] -> [EXIT]
 333    get the "real" basic block (block 2).  */
 334
 335 static basic_block
 336 get_real_block (function *fun)
 337 {
 338   ASSERT_TRUE (fun->cfg != NULL);
 339   ASSERT_EQ (3, n_basic_blocks_for_fn (fun));
 340   basic_block bb2 = (*fun->cfg->x_basic_block_info)[2];
 341   ASSERT_TRUE (bb2 != NULL);
 342   return bb2;
 343 }
 344
 345 /* Verify that we have a simple 3-block CFG: the two "fake" ones, and
 346    a "real" one:
 347      [ENTRY] -> [block2] -> [EXIT].  */
 348
 349 static void
 350 verify_three_block_cfg (function *fun)
 351 {
 352   ASSERT_TRUE (fun->cfg != NULL);
 353   ASSERT_EQ (3, n_basic_blocks_for_fn (fun));
 354   ASSERT_EQ (2, n_edges_for_fn (fun));
 355
 356   /* The "fake" basic blocks.  */
 357   basic_block entry = ENTRY_BLOCK_PTR_FOR_FN (fun);
 358   ASSERT_TRUE (entry != NULL);
 359   ASSERT_EQ (ENTRY_BLOCK, entry->index);
 360
 361   basic_block exit = EXIT_BLOCK_PTR_FOR_FN (fun);
 362   ASSERT_TRUE (exit != NULL);
 363   ASSERT_EQ (EXIT_BLOCK, exit->index);
 364
 365   /* The "real" basic block.  */
 366   basic_block bb2 = get_real_block (fun);
 367   ASSERT_TRUE (bb2 != NULL);
 368   ASSERT_EQ (2, bb2->index);
 369
 370   /* Verify connectivity.  */
 371   ASSERT_EQ (NULL, entry->preds);
 372   ASSERT_EQ (1, entry->succs->length ());
 373
 374   edge from_entry_to_bb2 = (*entry->succs)[0];
 375   ASSERT_EQ (entry, from_entry_to_bb2->src);
 376   ASSERT_EQ (bb2, from_entry_to_bb2->dest);
 377
 378   ASSERT_EQ (1, bb2->preds->length ());
 379   ASSERT_EQ (from_entry_to_bb2, (*bb2->preds)[0]);
 380   ASSERT_EQ (1, bb2->succs->length ());
 381
 382   edge from_bb2_to_exit = (*bb2->succs)[0];
 383   ASSERT_EQ (bb2, from_bb2_to_exit->src);
 384   ASSERT_EQ (exit, from_bb2_to_exit->dest);
 385
 386   ASSERT_EQ (1, exit->preds->length ());
 387   ASSERT_EQ (from_bb2_to_exit, (*exit->preds)[0]);
 388   ASSERT_EQ (NULL, exit->succs);
 389 }
 390
 391 /* As above, but additionally verify the gimple statements are sane.  */
 392
 393 static void
 394 verify_three_block_gimple_cfg (function *fun)
 395 {
 396   verify_three_block_cfg (fun);
 397
 398   /* The "fake" basic blocks should be flagged as gimple, but with have no
 399      statements.  */
 400   basic_block entry = ENTRY_BLOCK_PTR_FOR_FN (fun);
 401   ASSERT_TRUE (entry != NULL);
 402   ASSERT_EQ (0, entry->flags & BB_RTL);
 403   ASSERT_EQ (NULL, bb_seq (entry));
 404
 405   basic_block exit = EXIT_BLOCK_PTR_FOR_FN (fun);
 406   ASSERT_TRUE (exit != NULL);
 407   ASSERT_EQ (0, entry->flags & BB_RTL);
 408   ASSERT_EQ (NULL, bb_seq (exit));
 409
 410   /* The "real" basic block should be flagged as gimple, and have one
 411      or more statements.  */
 412   basic_block bb2 = get_real_block (fun);
 413   ASSERT_TRUE (bb2 != NULL);
 414   ASSERT_EQ (0, entry->flags & BB_RTL);
 415   ASSERT_TRUE (bb_seq (bb2) != NULL);
 416 }
 417
 418 /* As above, but additionally verify the RTL insns are sane.  */
 419
 420 void
 421 verify_three_block_rtl_cfg (function *fun)
 422 {
 423   verify_three_block_cfg (fun);
 424
 425   /* The "fake" basic blocks should be flagged as RTL, but with no
 426      insns.  */
 427   basic_block entry = ENTRY_BLOCK_PTR_FOR_FN (fun);
 428   ASSERT_TRUE (entry != NULL);
 429   ASSERT_EQ (BB_RTL, entry->flags & BB_RTL);
 430   ASSERT_EQ (NULL, BB_HEAD (entry));
 431
 432   basic_block exit = EXIT_BLOCK_PTR_FOR_FN (fun);
 433   ASSERT_TRUE (exit != NULL);
 434   ASSERT_EQ (BB_RTL, exit->flags & BB_RTL);
 435   ASSERT_EQ (NULL, BB_HEAD (exit));
 436
 437   /* The "real" basic block should be flagged as RTL, and have one
 438      or more insns.  */
 439   basic_block bb2 = get_real_block (fun);
 440   ASSERT_TRUE (bb2 != NULL);
 441   ASSERT_EQ (BB_RTL, bb2->flags & BB_RTL);
 442   ASSERT_TRUE (BB_HEAD (bb2) != NULL);
 443 }
 444
 445 /* Test converting our trivial function:
 446      int test_fn (void) { return 42; }
 447    to gimple form.  */
 448
 449 static void
 450 test_gimplification ()
 451 {
 452   tree fndecl = build_trivial_generic_function ();
 453
 454   /* Convert to gimple: */
 455   gimplify_function_tree (fndecl);
 456
 457   /* Verify that we got gimple out of it.  */
 458
 459   /* The function is now in GIMPLE form but the CFG has not been
 460      built yet.  */
 461
 462   /* We should have a struct function for the decl.  */
 463   function *fun = DECL_STRUCT_FUNCTION (fndecl);
 464   ASSERT_TRUE (fun != NULL);
 465   ASSERT_EQ (fndecl, fun->decl);
 466
 467   /* We expect a GIMPLE_BIND, with two gimple statements within it:
 468        tmp = 42;
 469        return tmp;  */
 470
 471   gimple_seq seq_fn_body = gimple_body (fndecl);
 472   ASSERT_TRUE (seq_fn_body != NULL);
 473   gimple *bind_stmt = gimple_seq_first_stmt (seq_fn_body);
 474   ASSERT_EQ (GIMPLE_BIND, gimple_code (bind_stmt));
 475   ASSERT_EQ (NULL, bind_stmt->next);
 476
 477   gimple_seq seq_bind_body = gimple_bind_body (as_a <gbind *> (bind_stmt));
 478
 479   /* Verify that we have the 2 statements we expect.  */
 480   ASSERT_TRUE (seq_bind_body != NULL);
 481   gimple *stmt1 = gimple_seq_first_stmt (seq_bind_body);
 482   ASSERT_TRUE (stmt1 != NULL);
 483   ASSERT_EQ (GIMPLE_ASSIGN, gimple_code (stmt1));
 484   gimple *stmt2 = stmt1->next;
 485   ASSERT_TRUE (stmt2 != NULL);
 486   ASSERT_EQ (stmt1, stmt2->prev);
 487   ASSERT_EQ (GIMPLE_RETURN, gimple_code (stmt2));
 488 }
 489
 490 /* Test of building a CFG for a function in high gimple form.  */
 491
 492 static void
 493 test_building_cfg ()
 494 {
 495   /* Construct a trivial function, and gimplify it: */
 496   tree fndecl = build_trivial_high_gimple_function ();
 497   function *fun = DECL_STRUCT_FUNCTION (fndecl);
 498   ASSERT_TRUE (fun != NULL);
 499
 500   /* Build a CFG.  */
 501   build_cfg (fndecl);
 502
 503   /* The CFG-building code constructs a 4-block cfg (with
 504      ENTRY and EXIT):
 505        test_fn ()
 506        {
 507          <bb 2>:
 508          D.65 = 42;
 509
 510          <bb 3>:
 511          return D.65;
 512        }
 513      and then ought to merge blocks 2 and 3 in cleanup_tree_cfg.
 514
 515      Hence we should end up with a simple 3-block cfg, the two "fake" ones,
 516      and a "real" one:
 517        [ENTRY] -> [block2] -> [EXIT]
 518      with code like this:
 519          test_fn ()
 520          {
 521            <bb 2>:
 522            D.56 = 42;
 523            return D.56;
 524          }
 525   */
 526   verify_three_block_gimple_cfg (fun);
 527
 528   /* Verify the statements within the "real" block.  */
 529   basic_block bb2 = get_real_block (fun);
 530   gimple *stmt_a = gimple_seq_first_stmt (bb_seq (bb2));
 531   ASSERT_EQ (GIMPLE_ASSIGN, gimple_code (stmt_a));
 532   gimple *stmt_b = stmt_a->next;
 533   ASSERT_EQ (GIMPLE_RETURN, gimple_code (stmt_b));
 534   ASSERT_EQ (NULL, stmt_b->next);
 535 }
 536
 537 /* Test of conversion of gimple to SSA form.  */
 538
 539 static void
 540 test_conversion_to_ssa ()
 541 {
 542   /* As above, construct a trivial function, gimplify it, and build a CFG: */
 543   tree fndecl = build_trivial_high_gimple_function ();
 544   function *fun = DECL_STRUCT_FUNCTION (fndecl);
 545   ASSERT_TRUE (fun != NULL);
 546   build_cfg (fndecl);
 547
 548   convert_to_ssa (fndecl);
 549
 550   verify_three_block_gimple_cfg (fun);
 551
 552   /* For out trivial test function we should now have something like
 553      this:
 554        test_fn ()
 555        {
 556          <bb 2>:
 557          _1 = 42;
 558          return _1;
 559        }
 560   */
 561   basic_block bb2 = get_real_block (fun);
 562   gimple *stmt_a = gimple_seq_first_stmt (bb_seq (bb2));
 563   ASSERT_EQ (GIMPLE_ASSIGN, gimple_code (stmt_a));
 564
 565   gimple *stmt_b = stmt_a->next;
 566   ASSERT_EQ (GIMPLE_RETURN, gimple_code (stmt_b));
 567   ASSERT_EQ (NULL, stmt_b->next);
 568
 569   greturn *return_stmt = as_a <greturn *> (stmt_b);
 570   ASSERT_EQ (SSA_NAME, TREE_CODE (gimple_return_retval (return_stmt)));
 571 }
 572
 573 /* Test range folding.  We must start this here because we need cfun
 574    set.  */
 575
 576 static void
 577 test_ranges ()
 578 {
 579   tree fndecl = build_trivial_high_gimple_function ();
 580   function *fun = DECL_STRUCT_FUNCTION (fndecl);
 581   push_cfun (fun);
 582   range_tests ();
 583   range_op_tests ();
 584
 585   build_cfg (fndecl);
 586   convert_to_ssa (fndecl);
 587   gimple_range_tests ();
 588
 589   pop_cfun ();
 590 }
 591
 592 /* Test of expansion from gimple-ssa to RTL.  */
 593
 594 static void
 595 test_expansion_to_rtl ()
 596 {
 597   /* As above, construct a trivial function, gimplify it, build a CFG,
 598      and convert to SSA: */
 599   tree fndecl = build_trivial_high_gimple_function ();
 600   function *fun = DECL_STRUCT_FUNCTION (fndecl);
 601   ASSERT_TRUE (fun != NULL);
 602   build_cfg (fndecl);
 603   convert_to_ssa (fndecl);
 604
 605   /* We need a cgraph_node for it.  */
 606   cgraph_node::get_create (fndecl);
 607   /* Normally, cgraph_node::expand () would call
 608      init_function_start (and a bunch of other stuff),
 609      and invoke the expand pass, but it also runs
 610      all of the other passes.  So just do the minimum
 611      needed to get from gimple-SSA to RTL.  */
 612   rtl_opt_pass *expand_pass = make_pass_expand (g);
 613   push_cfun (fun);
 614   init_function_start (fndecl);
 615   expand_pass->execute (fun);
 616   pop_cfun ();
 617   delete expand_pass;
 618
 619   /* On x86_64, I get this:
 620        (note 3 1 2 2 [bb 2] NOTE_INSN_BASIC_BLOCK)
 621        (note 2 3 5 2 NOTE_INSN_FUNCTION_BEG)
 622        (insn 5 2 6 2 (set (reg:SI 87 [ D.59 ])
 623                           (const_int 42 [0x2a])) -1 (nil))
 624        (insn 6 5 10 2 (set (reg:SI 88 [ <retval> ])
 625                            (reg:SI 87 [ D.59 ])) -1 (nil))
 626        (insn 10 6 11 2 (set (reg/i:SI 0 ax)
 627                             (reg:SI 88 [ <retval> ])) -1 (nil))
 628        (insn 11 10 0 2 (use (reg/i:SI 0 ax)) -1 (nil))
 629
 630      On cr16-elf I get this:
 631        (note 4 1 2 2 [bb 2] NOTE_INSN_BASIC_BLOCK)
 632        (insn 2 4 3 2 (set (reg:SI 24)
 633             (reg/f:SI 16 virtual-incoming-args)) -1
 634           (nil))
 635        (note 3 2 6 2 NOTE_INSN_FUNCTION_BEG)
 636        (insn 6 3 7 2 (set (reg:HI 22 [ _1 ])
 637             (const_int 42 [0x2a])) -1
 638          (nil))
 639        (insn 7 6 11 2 (set (reg:HI 23 [ <retval> ])
 640            (reg:HI 22 [ _1 ])) -1
 641          (nil))
 642        (insn 11 7 12 2 (set (reg/i:HI 0 r0)
 643            (reg:HI 23 [ <retval> ])) -1
 644          (nil))
 645        (insn 12 11 0 2 (use (reg/i:HI 0 r0)) -1
 646          (nil)).  */
 647   verify_three_block_rtl_cfg (fun);
 648
 649   /* Verify as much of the RTL as we can whilst avoiding
 650      target-specific behavior.  */
 651   basic_block bb2 = get_real_block (fun);
 652
 653   /* Expect a NOTE_INSN_BASIC_BLOCK... */
 654   rtx_insn *insn = BB_HEAD (bb2);
 655   ASSERT_TRUE (insn != NULL);
 656   ASSERT_EQ (NOTE, insn->code);
 657   ASSERT_EQ (NOTE_INSN_BASIC_BLOCK, NOTE_KIND (insn));
 658   ASSERT_EQ (bb2, NOTE_BASIC_BLOCK (insn));
 659
 660   /* ...etc; any further checks are likely to over-specify things
 661      and run us into target dependencies.  */
 662
 663   /* Verify that print_rtl_function is sane.  */
 664   named_temp_file tmp_out (".rtl");
 665   FILE *outfile = fopen (tmp_out.get_filename (), "w");
 666   print_rtx_function (outfile, fun, true);
 667   fclose (outfile);
 668
 669   char *dump = read_file (SELFTEST_LOCATION, tmp_out.get_filename ());
 670   ASSERT_STR_CONTAINS (dump, "(function \"test_fn\"\n");
 671   ASSERT_STR_CONTAINS (dump, "  (insn-chain\n");
 672   ASSERT_STR_CONTAINS (dump, "    (block 2\n");
 673   ASSERT_STR_CONTAINS (dump, "      (edge-from entry (flags \"FALLTHRU\"))\n");
 674   ASSERT_STR_CONTAINS (dump, "      (cinsn "); /* ...etc.  */
 675   ASSERT_STR_CONTAINS (dump, "      (edge-to exit (flags \"FALLTHRU\"))\n");
 676   ASSERT_STR_CONTAINS (dump, "    ) ;; block 2\n");
 677   ASSERT_STR_CONTAINS (dump, "  ) ;; insn-chain\n");
 678   ASSERT_STR_CONTAINS (dump, "  (crtl\n");
 679   ASSERT_STR_CONTAINS (dump, "  ) ;; crtl\n");
 680   ASSERT_STR_CONTAINS (dump, ") ;; function \"test_fn\"\n");
 681
 682   free (dump);
 683   free_after_compilation (fun);
 684 }
 685
 686 /* Run all of the selftests within this file.  */
 687
 688 void
 689 function_tests_c_tests ()
 690 {
 691   test_fndecl_int_void ();
 692   test_fndecl_float_intchar ();
 693   test_gimplification ();
 694   test_building_cfg ();
 695   test_conversion_to_ssa ();
 696   test_ranges ();
 697   test_expansion_to_rtl ();
 698 }
 699
 700 } // namespace selftest
 701
 702 #endif /* #if CHECKING_P */