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comparison gcc/tree-ssa-dse.c @ 67:f6334be47118

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update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
author nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
date Tue, 22 Mar 2011 17:18:12 +0900
parents b7f97abdc517
children 04ced10e8804
comparison
equal deleted inserted replaced
65:65488c3d617d 67:f6334be47118
25 #include "ggc.h" 25 #include "ggc.h"
26 #include "tree.h" 26 #include "tree.h"
27 #include "tm_p.h" 27 #include "tm_p.h"
28 #include "basic-block.h" 28 #include "basic-block.h"
29 #include "timevar.h" 29 #include "timevar.h"
30 #include "diagnostic.h"
31 #include "gimple-pretty-print.h" 30 #include "gimple-pretty-print.h"
32 #include "tree-flow.h" 31 #include "tree-flow.h"
33 #include "tree-pass.h" 32 #include "tree-pass.h"
34 #include "tree-dump.h" 33 #include "tree-dump.h"
35 #include "domwalk.h" 34 #include "domwalk.h"
81 global bitmap of stores when we finish processing a block. */ 80 global bitmap of stores when we finish processing a block. */
82 struct dse_block_local_data 81 struct dse_block_local_data
83 { 82 {
84 bitmap stores; 83 bitmap stores;
85 }; 84 };
85
86 /* Bitmap of blocks that have had EH statements cleaned. We should
87 remove their dead edges eventually. */
88 static bitmap need_eh_cleanup;
86 89
87 static bool gate_dse (void); 90 static bool gate_dse (void);
88 static unsigned int tree_ssa_dse (void); 91 static unsigned int tree_ssa_dse (void);
89 static void dse_initialize_block_local_data (struct dom_walk_data *, 92 static void dse_initialize_block_local_data (struct dom_walk_data *,
90 basic_block, 93 basic_block,
300 /* If we have precisely one immediate use at this point and the 303 /* If we have precisely one immediate use at this point and the
301 stores are to the same memory location or there is a chain of 304 stores are to the same memory location or there is a chain of
302 virtual uses from stmt and the stmt which stores to that same 305 virtual uses from stmt and the stmt which stores to that same
303 memory location, then we may have found redundant store. */ 306 memory location, then we may have found redundant store. */
304 if (bitmap_bit_p (dse_gd->stores, get_stmt_uid (use_stmt)) 307 if (bitmap_bit_p (dse_gd->stores, get_stmt_uid (use_stmt))
305 && operand_equal_p (gimple_assign_lhs (stmt), 308 && (operand_equal_p (gimple_assign_lhs (stmt),
306 gimple_assign_lhs (use_stmt), 0)) 309 gimple_assign_lhs (use_stmt), 0)
310 || stmt_kills_ref_p (use_stmt, gimple_assign_lhs (stmt))))
307 { 311 {
308 /* If use_stmt is or might be a nop assignment, e.g. for 312 /* If use_stmt is or might be a nop assignment, e.g. for
309 struct { ... } S a, b, *p; ... 313 struct { ... } S a, b, *p; ...
310 b = a; b = b; 314 b = a; b = b;
311 or 315 or
333 } 337 }
334 338
335 /* Then we need to fix the operand of the consuming stmt. */ 339 /* Then we need to fix the operand of the consuming stmt. */
336 unlink_stmt_vdef (stmt); 340 unlink_stmt_vdef (stmt);
337 341
342 bitmap_set_bit (need_eh_cleanup, gimple_bb (stmt)->index);
343
338 /* Remove the dead store. */ 344 /* Remove the dead store. */
339 gsi_remove (&gsi, true); 345 gsi_remove (&gsi, true);
340 346
341 /* And release any SSA_NAMEs set in this statement back to the 347 /* And release any SSA_NAMEs set in this statement back to the
342 SSA_NAME manager. */ 348 SSA_NAME manager. */
399 tree_ssa_dse (void) 405 tree_ssa_dse (void)
400 { 406 {
401 struct dom_walk_data walk_data; 407 struct dom_walk_data walk_data;
402 struct dse_global_data dse_gd; 408 struct dse_global_data dse_gd;
403 409
410 need_eh_cleanup = BITMAP_ALLOC (NULL);
411
404 renumber_gimple_stmt_uids (); 412 renumber_gimple_stmt_uids ();
405 413
406 /* We might consider making this a property of each pass so that it 414 /* We might consider making this a property of each pass so that it
407 can be [re]computed on an as-needed basis. Particularly since 415 can be [re]computed on an as-needed basis. Particularly since
408 this pass could be seen as an extension of DCE which needs post 416 this pass could be seen as an extension of DCE which needs post
433 fini_walk_dominator_tree (&walk_data); 441 fini_walk_dominator_tree (&walk_data);
434 442
435 /* Release the main bitmap. */ 443 /* Release the main bitmap. */
436 BITMAP_FREE (dse_gd.stores); 444 BITMAP_FREE (dse_gd.stores);
437 445
446 /* Removal of stores may make some EH edges dead. Purge such edges from
447 the CFG as needed. */
448 if (!bitmap_empty_p (need_eh_cleanup))
449 {
450 gimple_purge_all_dead_eh_edges (need_eh_cleanup);
451 cleanup_tree_cfg ();
452 }
453
454 BITMAP_FREE (need_eh_cleanup);
455
438 /* For now, just wipe the post-dominator information. */ 456 /* For now, just wipe the post-dominator information. */
439 free_dominance_info (CDI_POST_DOMINATORS); 457 free_dominance_info (CDI_POST_DOMINATORS);
440 return 0; 458 return 0;
441 } 459 }
442 460