/* CFG cleanup for trees.
- Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
Free Software Foundation, Inc.
This file is part of GCC.
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
-#include "rtl.h"
#include "tm_p.h"
-#include "hard-reg-set.h"
#include "basic-block.h"
#include "output.h"
-#include "toplev.h"
+#include "diagnostic-core.h"
#include "flags.h"
#include "function.h"
-#include "expr.h"
#include "ggc.h"
#include "langhooks.h"
-#include "diagnostic.h"
#include "tree-flow.h"
#include "timevar.h"
#include "tree-dump.h"
#include "tree-pass.h"
-#include "toplev.h"
#include "except.h"
#include "cfgloop.h"
#include "cfglayout.h"
/* For conditions try harder and lookup single-argument
PHI nodes. Only do so from the same basic-block though
as other basic-blocks may be dead already. */
- if (TREE_CODE (lhs) == SSA_NAME)
+ if (TREE_CODE (lhs) == SSA_NAME
+ && !name_registered_for_update_p (lhs))
{
gimple def_stmt = SSA_NAME_DEF_STMT (lhs);
if (gimple_code (def_stmt) == GIMPLE_PHI
&& gimple_phi_num_args (def_stmt) == 1
- && gimple_bb (def_stmt) == gimple_bb (stmt))
+ && gimple_bb (def_stmt) == gimple_bb (stmt)
+ && (TREE_CODE (PHI_ARG_DEF (def_stmt, 0)) != SSA_NAME
+ || !name_registered_for_update_p (PHI_ARG_DEF (def_stmt,
+ 0))))
lhs = PHI_ARG_DEF (def_stmt, 0);
}
- if (TREE_CODE (rhs) == SSA_NAME)
+ if (TREE_CODE (rhs) == SSA_NAME
+ && !name_registered_for_update_p (rhs))
{
gimple def_stmt = SSA_NAME_DEF_STMT (rhs);
if (gimple_code (def_stmt) == GIMPLE_PHI
&& gimple_phi_num_args (def_stmt) == 1
- && gimple_bb (def_stmt) == gimple_bb (stmt))
+ && gimple_bb (def_stmt) == gimple_bb (stmt)
+ && (TREE_CODE (PHI_ARG_DEF (def_stmt, 0)) != SSA_NAME
+ || !name_registered_for_update_p (PHI_ARG_DEF (def_stmt,
+ 0))))
rhs = PHI_ARG_DEF (def_stmt, 0);
}
val = fold_binary_loc (loc, gimple_cond_code (stmt),
tree_forwarder_block_p (basic_block bb, bool phi_wanted)
{
gimple_stmt_iterator gsi;
+ location_t locus;
/* BB must have a single outgoing edge. */
if (single_succ_p (bb) != 1
|| (single_succ_edge (bb)->flags & EDGE_ABNORMAL))
return false;
-#if ENABLE_CHECKING
- gcc_assert (bb != ENTRY_BLOCK_PTR);
-#endif
+ gcc_checking_assert (bb != ENTRY_BLOCK_PTR);
+
+ locus = single_succ_edge (bb)->goto_locus;
/* There should not be an edge coming from entry, or an EH edge. */
{
FOR_EACH_EDGE (e, ei, bb->preds)
if (e->src == ENTRY_BLOCK_PTR || (e->flags & EDGE_EH))
return false;
+ /* If goto_locus of any of the edges differs, prevent removing
+ the forwarder block for -O0. */
+ else if (optimize == 0 && e->goto_locus != locus)
+ return false;
}
/* Now walk through the statements backward. We can ignore labels,
case GIMPLE_LABEL:
if (DECL_NONLOCAL (gimple_label_label (stmt)))
return false;
+ if (optimize == 0 && gimple_location (stmt) != locus)
+ return false;
break;
/* ??? For now, hope there's a corresponding debug
return true;
}
-/* Return true if BB has at least one abnormal incoming edge. */
-
-static inline bool
-has_abnormal_incoming_edge_p (basic_block bb)
-{
- edge e;
- edge_iterator ei;
-
- FOR_EACH_EDGE (e, ei, bb->preds)
- if (e->flags & EDGE_ABNORMAL)
- return true;
-
- return false;
-}
-
/* If all the PHI nodes in DEST have alternatives for E1 and E2 and
those alternatives are equal in each of the PHI nodes, then return
true, else return false. */
So if there is an abnormal edge to BB, proceed only if there is
no abnormal edge to DEST and there are no phi nodes in DEST. */
- if (has_abnormal_incoming_edge_p (bb)
- && (has_abnormal_incoming_edge_p (dest)
+ if (bb_has_abnormal_pred (bb)
+ && (bb_has_abnormal_pred (dest)
|| !gimple_seq_empty_p (phi_nodes (dest))))
return false;
}
}
- can_move_debug_stmts = single_pred_p (dest);
+ can_move_debug_stmts = MAY_HAVE_DEBUG_STMTS && single_pred_p (dest);
/* Redirect the edges. */
for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
gsi_next (&gsi);
}
- /* Move debug statements if the destination has just a single
- predecessor. */
+ /* Move debug statements if the destination has a single predecessor. */
if (can_move_debug_stmts)
{
gsi_to = gsi_after_labels (dest);
return true;
}
+/* STMT is a call that has been discovered noreturn. Fixup the CFG
+ and remove LHS. Return true if something changed. */
+
+bool
+fixup_noreturn_call (gimple stmt)
+{
+ basic_block bb = gimple_bb (stmt);
+ bool changed = false;
+
+ if (gimple_call_builtin_p (stmt, BUILT_IN_RETURN))
+ return false;
+
+ /* First split basic block if stmt is not last. */
+ if (stmt != gsi_stmt (gsi_last_bb (bb)))
+ split_block (bb, stmt);
+
+ changed |= remove_fallthru_edge (bb->succs);
+
+ /* If there is LHS, remove it. */
+ if (gimple_call_lhs (stmt))
+ {
+ tree op = gimple_call_lhs (stmt);
+ gimple_call_set_lhs (stmt, NULL_TREE);
+
+ /* We need to remove SSA name to avoid checking errors.
+ All uses are dominated by the noreturn and thus will
+ be removed afterwards.
+ We proactively remove affected non-PHI statements to avoid
+ fixup_cfg from trying to update them and crashing. */
+ if (TREE_CODE (op) == SSA_NAME)
+ {
+ use_operand_p use_p;
+ imm_use_iterator iter;
+ gimple use_stmt;
+ bitmap_iterator bi;
+ unsigned int bb_index;
+
+ bitmap blocks = BITMAP_ALLOC (NULL);
+
+ FOR_EACH_IMM_USE_STMT (use_stmt, iter, op)
+ {
+ if (gimple_code (use_stmt) != GIMPLE_PHI)
+ bitmap_set_bit (blocks, gimple_bb (use_stmt)->index);
+ else
+ FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
+ SET_USE (use_p, error_mark_node);
+ }
+ EXECUTE_IF_SET_IN_BITMAP (blocks, 0, bb_index, bi)
+ delete_basic_block (BASIC_BLOCK (bb_index));
+ BITMAP_FREE (blocks);
+ release_ssa_name (op);
+ }
+ update_stmt (stmt);
+ changed = true;
+ }
+ /* Similarly remove VDEF if there is any. */
+ else if (gimple_vdef (stmt))
+ update_stmt (stmt);
+ return changed;
+}
+
+
/* Split basic blocks on calls in the middle of a basic block that are now
known not to return, and remove the unreachable code. */
BB is present in the cfg. */
if (bb == NULL
|| bb->index < NUM_FIXED_BLOCKS
- || bb->index >= n_basic_blocks
+ || bb->index >= last_basic_block
|| BASIC_BLOCK (bb->index) != bb
- || last_stmt (bb) == stmt
|| !gimple_call_noreturn_p (stmt))
continue;
- changed = true;
- split_block (bb, stmt);
- remove_fallthru_edge (bb->succs);
+ changed |= fixup_noreturn_call (stmt);
}
return changed;
}
-/* If GIMPLE_OMP_RETURN in basic block BB is unreachable, remove it. */
-
-static bool
-cleanup_omp_return (basic_block bb)
-{
- gimple stmt = last_stmt (bb);
- basic_block control_bb;
-
- if (stmt == NULL
- || gimple_code (stmt) != GIMPLE_OMP_RETURN
- || !single_pred_p (bb))
- return false;
-
- control_bb = single_pred (bb);
- stmt = last_stmt (control_bb);
-
- if (stmt == NULL || gimple_code (stmt) != GIMPLE_OMP_SECTIONS_SWITCH)
- return false;
-
- /* The block with the control statement normally has two entry edges -- one
- from entry, one from continue. If continue is removed, return is
- unreachable, so we remove it here as well. */
- if (EDGE_COUNT (control_bb->preds) == 2)
- return false;
-
- gcc_assert (EDGE_COUNT (control_bb->preds) == 1);
- remove_edge_and_dominated_blocks (single_pred_edge (bb));
- return true;
-}
-
/* Tries to cleanup cfg in basic block BB. Returns true if anything
changes. */
static bool
cleanup_tree_cfg_bb (basic_block bb)
{
- bool retval = false;
-
- if (cleanup_omp_return (bb))
- return true;
-
- retval = cleanup_control_flow_bb (bb);
+ bool retval = cleanup_control_flow_bb (bb);
- /* Forwarder blocks can carry line number information which is
- useful when debugging, so we only clean them up when
- optimizing. */
- if (optimize > 0
- && tree_forwarder_block_p (bb, false)
+ if (tree_forwarder_block_p (bb, false)
&& remove_forwarder_block (bb))
return true;
static void
repair_loop_structures (void)
{
- bitmap changed_bbs = BITMAP_ALLOC (NULL);
+ bitmap changed_bbs;
+
+ timevar_push (TV_REPAIR_LOOPS);
+ changed_bbs = BITMAP_ALLOC (NULL);
fix_loop_structure (changed_bbs);
/* This usually does nothing. But sometimes parts of cfg that originally
scev_reset ();
loops_state_clear (LOOPS_NEED_FIXUP);
+ timevar_pop (TV_REPAIR_LOOPS);
}
/* Cleanup cfg and repair loop structures. */
redirection, replace it with the PHI argument that used
to be on E. */
head = redirect_edge_var_map_vector (e);
- for (i = 0; VEC_iterate (edge_var_map, head, i, vm); ++i)
+ FOR_EACH_VEC_ELT (edge_var_map, head, i, vm)
{
tree old_arg = redirect_edge_var_map_result (vm);
tree new_arg = redirect_edge_var_map_def (vm);
if (gimple_seq_empty_p (phi_nodes (dest))
/* We don't want to deal with a basic block with
abnormal edges. */
- || has_abnormal_incoming_edge_p (bb))
+ || bb_has_abnormal_pred (bb))
continue;
if (!dominated_by_p (CDI_DOMINATORS, dest, bb))
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func | TODO_ggc_collect /* todo_flags_finish */
+ TODO_ggc_collect /* todo_flags_finish */
| TODO_verify_ssa
}
};
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