set_register_defs (stmt, false);
set_rewrite_uses (stmt, false);
+ if (is_gimple_debug (stmt))
+ return;
+
/* If a variable is used before being set, then the variable is live
across a block boundary, so mark it live-on-entry to BB. */
FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
VEC_replace (gimple_vec, phis_to_rewrite, idx, phis);
}
-
/* Insert PHI nodes for variable VAR using the iterated dominance
frontier given in PHI_INSERTION_POINTS. If UPDATE_P is true, this
function assumes that the caller is incrementally updating the
}
else
{
+ tree tracked_var;
+
gcc_assert (DECL_P (var));
phi = create_phi_node (var, bb);
+
+ tracked_var = target_for_debug_bind (var);
+ if (tracked_var)
+ {
+ gimple note = gimple_build_debug_bind (tracked_var,
+ PHI_RESULT (phi),
+ phi);
+ gimple_stmt_iterator si = gsi_after_labels (bb);
+ gsi_insert_before (&si, note, GSI_SAME_STMT);
+ }
}
/* Mark this PHI node as interesting for update_ssa. */
definition of a variable when a new real or virtual definition is found. */
static void
-rewrite_stmt (gimple stmt)
+rewrite_stmt (gimple_stmt_iterator si)
{
use_operand_p use_p;
def_operand_p def_p;
ssa_op_iter iter;
+ gimple stmt = gsi_stmt (si);
/* If mark_def_sites decided that we don't need to rewrite this
statement, ignore it. */
FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF)
{
tree var = DEF_FROM_PTR (def_p);
+ tree name = make_ssa_name (var, stmt);
+ tree tracked_var;
gcc_assert (DECL_P (var));
- SET_DEF (def_p, make_ssa_name (var, stmt));
+ SET_DEF (def_p, name);
register_new_def (DEF_FROM_PTR (def_p), var);
+
+ tracked_var = target_for_debug_bind (var);
+ if (tracked_var)
+ {
+ gimple note = gimple_build_debug_bind (tracked_var, name, stmt);
+ gsi_insert_after (&si, note, GSI_SAME_STMT);
+ }
}
}
of a variable when a new real or virtual definition is found. */
if (TEST_BIT (interesting_blocks, bb->index))
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
- rewrite_stmt (gsi_stmt (gsi));
+ rewrite_stmt (gsi);
/* Step 3. Visit all the successor blocks of BB looking for PHI nodes.
For every PHI node found, add a new argument containing the current
}
+/* Same as maybe_replace_use, but without introducing default stmts,
+ returning false to indicate a need to do so. */
+
+static inline bool
+maybe_replace_use_in_debug_stmt (use_operand_p use_p)
+{
+ tree rdef = NULL_TREE;
+ tree use = USE_FROM_PTR (use_p);
+ tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use);
+
+ if (symbol_marked_for_renaming (sym))
+ rdef = get_current_def (sym);
+ else if (is_old_name (use))
+ {
+ rdef = get_current_def (use);
+ /* We can't assume that, if there's no current definition, the
+ default one should be used. It could be the case that we've
+ rearranged blocks so that the earlier definition no longer
+ dominates the use. */
+ if (!rdef && SSA_NAME_IS_DEFAULT_DEF (use))
+ rdef = use;
+ }
+ else
+ rdef = use;
+
+ if (rdef && rdef != use)
+ SET_USE (use_p, rdef);
+
+ return rdef != NULL_TREE;
+}
+
+
/* If the operand pointed to by DEF_P is an SSA name in NEW_SSA_NAMES
or OLD_SSA_NAMES, or if it is a symbol marked for renaming,
register it as the current definition for the names replaced by
DEF_P. */
static inline void
-maybe_register_def (def_operand_p def_p, gimple stmt)
+maybe_register_def (def_operand_p def_p, gimple stmt,
+ gimple_stmt_iterator gsi)
{
tree def = DEF_FROM_PTR (def_p);
tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def);
{
if (DECL_P (def))
{
+ tree tracked_var;
+
def = make_ssa_name (def, stmt);
SET_DEF (def_p, def);
+
+ tracked_var = target_for_debug_bind (sym);
+ if (tracked_var)
+ {
+ gimple note = gimple_build_debug_bind (tracked_var, def, stmt);
+ gsi_insert_after (&gsi, note, GSI_SAME_STMT);
+ }
}
register_new_update_single (def, sym);
in OLD_SSA_NAMES. */
static void
-rewrite_update_stmt (gimple stmt)
+rewrite_update_stmt (gimple stmt, gimple_stmt_iterator gsi)
{
use_operand_p use_p;
def_operand_p def_p;
/* Rewrite USES included in OLD_SSA_NAMES and USES whose underlying
symbol is marked for renaming. */
if (rewrite_uses_p (stmt))
- FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES)
- maybe_replace_use (use_p);
+ {
+ if (is_gimple_debug (stmt))
+ {
+ bool failed = false;
+
+ FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
+ if (!maybe_replace_use_in_debug_stmt (use_p))
+ {
+ failed = true;
+ break;
+ }
+
+ if (failed)
+ {
+ /* DOM sometimes threads jumps in such a way that a
+ debug stmt ends up referencing a SSA variable that no
+ longer dominates the debug stmt, but such that all
+ incoming definitions refer to the same definition in
+ an earlier dominator. We could try to recover that
+ definition somehow, but this will have to do for now.
+
+ Introducing a default definition, which is what
+ maybe_replace_use() would do in such cases, may
+ modify code generation, for the otherwise-unused
+ default definition would never go away, modifying SSA
+ version numbers all over. */
+ gimple_debug_bind_reset_value (stmt);
+ update_stmt (stmt);
+ }
+ }
+ else
+ {
+ FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES)
+ maybe_replace_use (use_p);
+ }
+ }
/* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES.
Also register definitions for names whose underlying symbol is
marked for renaming. */
if (register_defs_p (stmt))
FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS)
- maybe_register_def (def_p, stmt);
+ maybe_register_def (def_p, stmt, gsi);
}
/* Step 2. Rewrite every variable used in each statement in the block. */
if (TEST_BIT (interesting_blocks, bb->index))
- {
- gcc_assert (bitmap_bit_p (blocks_to_update, bb->index));
+ {
+ gcc_assert (bitmap_bit_p (blocks_to_update, bb->index));
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
- rewrite_update_stmt (gsi_stmt (gsi));
- }
+ rewrite_update_stmt (gsi_stmt (gsi), gsi);
+ }
/* Step 3. Update PHI nodes. */
rewrite_update_phi_arguments (bb);
BITMAP_FREE (dfs[bb->index]);
free (dfs);
+ sbitmap_free (interesting_blocks);
+
fini_ssa_renamer ();
timevar_pop (TV_TREE_SSA_OTHER);
if (gimple_code (stmt) == GIMPLE_PHI)
mark_phi_for_rewrite (def_bb, stmt);
else
- set_rewrite_uses (stmt, true);
+ {
+ set_rewrite_uses (stmt, true);
+
+ if (is_gimple_debug (stmt))
+ return;
+ }
/* If VAR has not been defined in BB, then it is live-on-entry
to BB. Note that we cannot just use the block holding VAR's
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