diff options
Diffstat (limited to 'gcc/tree-ssa-loop-manip.c')
| -rw-r--r-- | gcc/tree-ssa-loop-manip.c | 165 |
1 files changed, 52 insertions, 113 deletions
diff --git a/gcc/tree-ssa-loop-manip.c b/gcc/tree-ssa-loop-manip.c index 02b21a3..f16ec3f 100644 --- a/gcc/tree-ssa-loop-manip.c +++ b/gcc/tree-ssa-loop-manip.c @@ -139,11 +139,9 @@ add_exit_phis_edge (basic_block exit, tree use) return; phi = create_phi_node (use, exit); - + create_new_def_for (PHI_RESULT (phi), phi, PHI_RESULT_PTR (phi)); FOR_EACH_EDGE (e, ei, exit->preds) add_phi_arg (phi, use, e); - - SSA_NAME_DEF_STMT (use) = def_stmt; } /* Add exit phis for VAR that is used in LIVEIN. @@ -215,10 +213,11 @@ get_loops_exits (void) /* For USE in BB, if it is used outside of the loop it is defined in, mark it for rewrite. Record basic block BB where it is used - to USE_BLOCKS. */ + to USE_BLOCKS. Record the ssa name index to NEED_PHIS bitmap. */ static void -find_uses_to_rename_use (basic_block bb, tree use, bitmap *use_blocks) +find_uses_to_rename_use (basic_block bb, tree use, bitmap *use_blocks, + bitmap need_phis) { unsigned ver; basic_block def_bb; @@ -227,6 +226,10 @@ find_uses_to_rename_use (basic_block bb, tree use, bitmap *use_blocks) if (TREE_CODE (use) != SSA_NAME) return; + /* We don't need to keep virtual operands in loop-closed form. */ + if (!is_gimple_reg (use)) + return; + ver = SSA_NAME_VERSION (use); def_bb = bb_for_stmt (SSA_NAME_DEF_STMT (use)); if (!def_bb) @@ -241,31 +244,32 @@ find_uses_to_rename_use (basic_block bb, tree use, bitmap *use_blocks) use_blocks[ver] = BITMAP_ALLOC (NULL); bitmap_set_bit (use_blocks[ver], bb->index); - if (!flow_bb_inside_loop_p (def_loop, bb)) - mark_for_rewrite (use); + bitmap_set_bit (need_phis, ver); } /* For uses in STMT, mark names that are used outside of the loop they are defined to rewrite. Record the set of blocks in that the ssa - names are defined to USE_BLOCKS. */ + names are defined to USE_BLOCKS and the ssa names themselves to + NEED_PHIS. */ static void -find_uses_to_rename_stmt (tree stmt, bitmap *use_blocks) +find_uses_to_rename_stmt (tree stmt, bitmap *use_blocks, bitmap need_phis) { ssa_op_iter iter; tree var; basic_block bb = bb_for_stmt (stmt); FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_USES | SSA_OP_ALL_KILLS) - find_uses_to_rename_use (bb, var, use_blocks); + find_uses_to_rename_use (bb, var, use_blocks, need_phis); } /* Marks names that are used in BB and outside of the loop they are defined in for rewrite. Records the set of blocks in that the ssa - names are defined to USE_BLOCKS. */ + names are defined to USE_BLOCKS. Record the SSA names that will + need exit PHIs in NEED_PHIS. */ static void -find_uses_to_rename_bb (basic_block bb, bitmap *use_blocks) +find_uses_to_rename_bb (basic_block bb, bitmap *use_blocks, bitmap need_phis) { block_stmt_iterator bsi; edge e; @@ -275,10 +279,10 @@ find_uses_to_rename_bb (basic_block bb, bitmap *use_blocks) FOR_EACH_EDGE (e, ei, bb->succs) for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi)) find_uses_to_rename_use (bb, PHI_ARG_DEF_FROM_EDGE (phi, e), - use_blocks); + use_blocks, need_phis); for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) - find_uses_to_rename_stmt (bsi_stmt (bsi), use_blocks); + find_uses_to_rename_stmt (bsi_stmt (bsi), use_blocks, need_phis); } /* Marks names that are used outside of the loop they are defined in @@ -287,24 +291,24 @@ find_uses_to_rename_bb (basic_block bb, bitmap *use_blocks) scan only blocks in this set. */ static void -find_uses_to_rename (bitmap changed_bbs, bitmap *use_blocks) +find_uses_to_rename (bitmap changed_bbs, bitmap *use_blocks, bitmap need_phis) { basic_block bb; unsigned index; bitmap_iterator bi; - if (changed_bbs) + if (changed_bbs && !bitmap_empty_p (changed_bbs)) { EXECUTE_IF_SET_IN_BITMAP (changed_bbs, 0, index, bi) { - find_uses_to_rename_bb (BASIC_BLOCK (index), use_blocks); + find_uses_to_rename_bb (BASIC_BLOCK (index), use_blocks, need_phis); } } else { FOR_EACH_BB (bb) { - find_uses_to_rename_bb (bb, use_blocks); + find_uses_to_rename_bb (bb, use_blocks, need_phis); } } } @@ -336,43 +340,42 @@ find_uses_to_rename (bitmap changed_bbs, bitmap *use_blocks) base 99 and step 1. If CHANGED_BBS is not NULL, we look for uses outside loops only in - the basic blocks in this set. */ + the basic blocks in this set. + + UPDATE_FLAG is used in the call to update_ssa. See + TODO_update_ssa* for documentation. */ void -rewrite_into_loop_closed_ssa (bitmap changed_bbs) +rewrite_into_loop_closed_ssa (bitmap changed_bbs, unsigned update_flag) { bitmap loop_exits = get_loops_exits (); bitmap *use_blocks; - unsigned i; - bitmap names_to_rename; + unsigned i, old_num_ssa_names; + bitmap names_to_rename = BITMAP_ALLOC (NULL); - gcc_assert (!any_marked_for_rewrite_p ()); + /* If the pass has caused the SSA form to be out-of-date, update it + now. */ + update_ssa (update_flag); - use_blocks = xcalloc (num_ssa_names, sizeof (bitmap)); + old_num_ssa_names = num_ssa_names; + use_blocks = xcalloc (old_num_ssa_names, sizeof (bitmap)); /* Find the uses outside loops. */ - find_uses_to_rename (changed_bbs, use_blocks); + find_uses_to_rename (changed_bbs, use_blocks, names_to_rename); - if (!any_marked_for_rewrite_p ()) - { - free (use_blocks); - BITMAP_FREE (loop_exits); - return; - } - - /* Add the phi nodes on exits of the loops for the names we need to + /* Add the PHI nodes on exits of the loops for the names we need to rewrite. */ - names_to_rename = marked_ssa_names (); add_exit_phis (names_to_rename, use_blocks, loop_exits); - for (i = 0; i < num_ssa_names; i++) + for (i = 0; i < old_num_ssa_names; i++) BITMAP_FREE (use_blocks[i]); free (use_blocks); BITMAP_FREE (loop_exits); BITMAP_FREE (names_to_rename); - /* Do the rewriting. */ - rewrite_ssa_into_ssa (); + /* Fix up all the names found to be used outside their original + loops. */ + update_ssa (TODO_update_ssa); } /* Check invariants of the loop closed ssa form for the USE in BB. */ @@ -383,7 +386,7 @@ check_loop_closed_ssa_use (basic_block bb, tree use) tree def; basic_block def_bb; - if (TREE_CODE (use) != SSA_NAME) + if (TREE_CODE (use) != SSA_NAME || !is_gimple_reg (use)) return; def = SSA_NAME_DEF_STMT (use); @@ -400,7 +403,7 @@ check_loop_closed_ssa_stmt (basic_block bb, tree stmt) ssa_op_iter iter; tree var; - FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_USES) + FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_USES | SSA_OP_ALL_KILLS) check_loop_closed_ssa_use (bb, var); } @@ -414,6 +417,9 @@ verify_loop_closed_ssa (void) tree phi; unsigned i; + if (current_loops == NULL) + return; + verify_ssa (false); FOR_EACH_BB (bb) @@ -566,53 +572,15 @@ copy_phi_node_args (unsigned first_new_block) BASIC_BLOCK (i)->rbi->duplicated = 0; } -/* Renames variables in the area copied by tree_duplicate_loop_to_header_edge. - FIRST_NEW_BLOCK is the first block in the copied area. DEFINITIONS is - a bitmap of all ssa names defined inside the loop. */ - -static void -rename_variables (unsigned first_new_block, bitmap definitions) -{ - unsigned i, copy_number = 0; - basic_block bb; - htab_t ssa_name_map = NULL; - - for (i = first_new_block; i < (unsigned) last_basic_block; i++) - { - bb = BASIC_BLOCK (i); - /* We assume that first come all blocks from the first copy, then all - blocks from the second copy, etc. */ - if (copy_number != (unsigned) bb->rbi->copy_number) - { - allocate_ssa_names (definitions, &ssa_name_map); - copy_number = bb->rbi->copy_number; - } +/* The same as cfgloopmanip.c:duplicate_loop_to_header_edge, but also + updates the PHI nodes at start of the copied region. In order to + achieve this, only loops whose exits all lead to the same location + are handled. - rewrite_to_new_ssa_names_bb (bb, ssa_name_map); - } - - htab_delete (ssa_name_map); -} - -/* Sets SSA_NAME_DEF_STMT for results of all phi nodes in BB. */ - -static void -set_phi_def_stmts (basic_block bb) -{ - tree phi; - - for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) - SSA_NAME_DEF_STMT (PHI_RESULT (phi)) = phi; -} - -/* The same as cfgloopmanip.c:duplicate_loop_to_header_edge, but also updates - ssa. In order to achieve this, only loops whose exits all lead to the same - location are handled. - - FIXME: we create some degenerate phi nodes that could be avoided by copy - propagating them instead. Unfortunately this is not completely - straightforward due to problems with constant folding. */ + Notice that we do not completely update the SSA web after + duplication. The caller is responsible for calling update_ssa + after the loop has been duplicated. */ bool tree_duplicate_loop_to_header_edge (struct loop *loop, edge e, @@ -622,9 +590,6 @@ tree_duplicate_loop_to_header_edge (struct loop *loop, edge e, unsigned int *n_to_remove, int flags) { unsigned first_new_block; - basic_block bb; - unsigned i; - bitmap definitions; if (!(loops->state & LOOPS_HAVE_SIMPLE_LATCHES)) return false; @@ -635,8 +600,6 @@ tree_duplicate_loop_to_header_edge (struct loop *loop, edge e, verify_loop_closed_ssa (); #endif - gcc_assert (!any_marked_for_rewrite_p ()); - first_new_block = last_basic_block; if (!duplicate_loop_to_header_edge (loop, e, loops, ndupl, wont_exit, orig, to_remove, n_to_remove, flags)) @@ -648,31 +611,7 @@ tree_duplicate_loop_to_header_edge (struct loop *loop, edge e, /* Copy the phi node arguments. */ copy_phi_node_args (first_new_block); - /* Rename the variables. */ - definitions = marked_ssa_names (); - rename_variables (first_new_block, definitions); - unmark_all_for_rewrite (); - BITMAP_FREE (definitions); - - /* For some time we have the identical ssa names as results in multiple phi - nodes. When phi node is resized, it sets SSA_NAME_DEF_STMT of its result - to the new copy. This means that we cannot easily ensure that the ssa - names defined in those phis are pointing to the right one -- so just - recompute SSA_NAME_DEF_STMT for them. */ - - for (i = first_new_block; i < (unsigned) last_basic_block; i++) - { - bb = BASIC_BLOCK (i); - set_phi_def_stmts (bb); - if (bb->rbi->copy_number == 1) - set_phi_def_stmts (bb->rbi->original); - } - scev_reset (); -#ifdef ENABLE_CHECKING - verify_loop_closed_ssa (); -#endif return true; } - |