#include "cfgloop.h"
#include "cfglayout.h"
#include "hashtab.h"
+#include "tree-ssa-propagate.h"
/* This file contains functions for building the Control Flow Graph (CFG)
for a function tree. */
}
}
+#ifdef ENABLE_CHECKING
+ verify_stmts ();
+#endif
+
/* Dump a textual representation of the flowgraph. */
if (dump_file)
dump_tree_cfg (dump_file, dump_flags);
/* Fold COND_EXPR_COND of each COND_EXPR. */
-static void
+void
fold_cond_expr_cond (void)
{
basic_block bb;
{
tree stmt;
block_stmt_iterator bsi;
+ tree phi;
if (!single_succ_p (a))
return false;
&& DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
return false;
- /* There may be no PHI nodes at the start of B. */
- if (phi_nodes (b))
- return false;
+ /* It must be possible to eliminate all phi nodes in B. If ssa form
+ is not up-to-date, we cannot eliminate any phis. */
+ phi = phi_nodes (b);
+ if (phi)
+ {
+ if (need_ssa_update_p ())
+ return false;
+
+ for (; phi; phi = PHI_CHAIN (phi))
+ if (!is_gimple_reg (PHI_RESULT (phi))
+ && !may_propagate_copy (PHI_RESULT (phi), PHI_ARG_DEF (phi, 0)))
+ return false;
+ }
/* Do not remove user labels. */
for (bsi = bsi_start (b); !bsi_end_p (bsi); bsi_next (&bsi))
return true;
}
+/* Replaces all uses of NAME by VAL. */
+
+void
+replace_uses_by (tree name, tree val)
+{
+ imm_use_iterator imm_iter;
+ use_operand_p use;
+ tree stmt;
+ edge e;
+ unsigned i;
+ VEC(tree,heap) *stmts = VEC_alloc (tree, heap, 20);
+
+ FOR_EACH_IMM_USE_SAFE (use, imm_iter, name)
+ {
+ stmt = USE_STMT (use);
+
+ SET_USE (use, val);
+
+ if (TREE_CODE (stmt) == PHI_NODE)
+ {
+ e = PHI_ARG_EDGE (stmt, PHI_ARG_INDEX_FROM_USE (use));
+ if (e->flags & EDGE_ABNORMAL)
+ {
+ /* This can only occur for virtual operands, since
+ for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
+ would prevent replacement. */
+ gcc_assert (!is_gimple_reg (name));
+ SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
+ }
+ }
+ else
+ VEC_safe_push (tree, heap, stmts, stmt);
+ }
+
+ /* We do not update the statements in the loop above. Consider
+ x = w * w;
+
+ If we performed the update in the first loop, the statement
+ would be rescanned after first occurrence of w is replaced,
+ the new uses would be placed to the beginning of the list,
+ and we would never process them. */
+ for (i = 0; VEC_iterate (tree, stmts, i, stmt); i++)
+ {
+ tree rhs;
+
+ fold_stmt_inplace (stmt);
+
+ rhs = get_rhs (stmt);
+ if (TREE_CODE (rhs) == ADDR_EXPR)
+ recompute_tree_invarant_for_addr_expr (rhs);
+
+ update_stmt (stmt);
+ }
+
+ VEC_free (tree, heap, stmts);
+}
/* Merge block B into block A. */
{
block_stmt_iterator bsi;
tree_stmt_iterator last;
+ tree phi;
if (dump_file)
fprintf (dump_file, "Merging blocks %d and %d\n", a->index, b->index);
+ /* Remove the phi nodes. */
+ bsi = bsi_last (a);
+ for (phi = phi_nodes (b); phi; phi = phi_nodes (b))
+ {
+ tree def = PHI_RESULT (phi), use = PHI_ARG_DEF (phi, 0);
+ tree copy;
+
+ if (!may_propagate_copy (def, use)
+ /* Propagating pointers might cause the set of vops for statements
+ to be changed, and thus require ssa form update. */
+ || (is_gimple_reg (def)
+ && POINTER_TYPE_P (TREE_TYPE (def))))
+ {
+ gcc_assert (is_gimple_reg (def));
+
+ /* Note that just emitting the copies is fine -- there is no problem
+ with ordering of phi nodes. This is because A is the single
+ predecessor of B, therefore results of the phi nodes cannot
+ appear as arguments of the phi nodes. */
+ copy = build2 (MODIFY_EXPR, void_type_node, def, use);
+ bsi_insert_after (&bsi, copy, BSI_NEW_STMT);
+ SET_PHI_RESULT (phi, NULL_TREE);
+ SSA_NAME_DEF_STMT (def) = copy;
+ }
+ else
+ replace_uses_by (def, use);
+ remove_phi_node (phi, NULL);
+ }
+
/* Ensure that B follows A. */
move_block_after (b, a);
edge e;
edge_iterator ei;
- if (warn_missing_noreturn
- && !TREE_THIS_VOLATILE (cfun->decl)
- && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
- && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
- warning (0, "%Jfunction might be possible candidate for "
- "attribute %<noreturn%>",
- cfun->decl);
-
/* If we have a path to EXIT, then we do return. */
if (TREE_THIS_VOLATILE (cfun->decl)
&& EDGE_COUNT (EXIT_BLOCK_PTR->preds) > 0)
0, /* todo_flags_finish */
0 /* letter */
};
+
+/* Emit noreturn warnings. */
+
+static void
+execute_warn_function_noreturn (void)
+{
+ if (warn_missing_noreturn
+ && !TREE_THIS_VOLATILE (cfun->decl)
+ && EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0
+ && !lang_hooks.function.missing_noreturn_ok_p (cfun->decl))
+ warning (0, "%Jfunction might be possible candidate for "
+ "attribute %<noreturn%>",
+ cfun->decl);
+}
+
+struct tree_opt_pass pass_warn_function_noreturn =
+{
+ NULL, /* name */
+ NULL, /* gate */
+ execute_warn_function_noreturn, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ 0, /* tv_id */
+ PROP_cfg, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ 0, /* todo_flags_finish */
+ 0 /* letter */
+};
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