+ r_arity = arity+1;
+ NEW_ARR_A (ir_node *, r_in, r_arity);
+ r_in[0] = callee;
+ memcpy (&r_in[1], in, sizeof (ir_node *) * arity);
+
+ res = new_ir_node (db, irg, block, op_FuncCall, mode_T, r_arity, r_in);
+
+ assert(is_method_type(tp));
+ set_FuncCall_type(res, tp);
+ res->attr.call.callee_arr = NULL;
+ res = optimize_node (res);
+ irn_vrfy_irg (res, irg);
+ return res;
+}
+
+
+INLINE ir_node *new_r_Block (ir_graph *irg, int arity, ir_node **in) {
+ return new_rd_Block(NULL, irg, arity, in);
+}
+INLINE ir_node *new_r_Start (ir_graph *irg, ir_node *block) {
+ return new_rd_Start(NULL, irg, block);
+}
+INLINE ir_node *new_r_End (ir_graph *irg, ir_node *block) {
+ return new_rd_End(NULL, irg, block);
+}
+INLINE ir_node *new_r_Jmp (ir_graph *irg, ir_node *block) {
+ return new_rd_Jmp(NULL, irg, block);
+}
+INLINE ir_node *new_r_Cond (ir_graph *irg, ir_node *block, ir_node *c) {
+ return new_rd_Cond(NULL, irg, block, c);
+}
+INLINE ir_node *new_r_Return (ir_graph *irg, ir_node *block,
+ ir_node *store, int arity, ir_node **in) {
+ return new_rd_Return(NULL, irg, block, store, arity, in);
+}
+INLINE ir_node *new_r_Raise (ir_graph *irg, ir_node *block,
+ ir_node *store, ir_node *obj) {
+ return new_rd_Raise(NULL, irg, block, store, obj);
+}
+INLINE ir_node *new_r_Const (ir_graph *irg, ir_node *block,
+ ir_mode *mode, tarval *con) {
+ return new_rd_Const(NULL, irg, block, mode, con);
+}
+INLINE ir_node *new_r_SymConst (ir_graph *irg, ir_node *block,
+ type_or_id_p value, symconst_kind symkind) {
+ return new_rd_SymConst(NULL, irg, block, value, symkind);
+}
+INLINE ir_node *new_r_Sel (ir_graph *irg, ir_node *block, ir_node *store,
+ ir_node *objptr, int n_index, ir_node **index,
+ entity *ent) {
+ return new_rd_Sel(NULL, irg, block, store, objptr, n_index, index, ent);
+}
+INLINE ir_node *new_r_InstOf (ir_graph *irg, ir_node *block, ir_node *store, ir_node *objptr,
+ type *ent) {
+ return (new_rd_InstOf (NULL, irg, block, store, objptr, ent));
+}
+INLINE ir_node *new_r_Call (ir_graph *irg, ir_node *block, ir_node *store,
+ ir_node *callee, int arity, ir_node **in,
+ type *tp) {
+ return new_rd_Call(NULL, irg, block, store, callee, arity, in, tp);
+}
+INLINE ir_node *new_r_Add (ir_graph *irg, ir_node *block,
+ ir_node *op1, ir_node *op2, ir_mode *mode) {
+ return new_rd_Add(NULL, irg, block, op1, op2, mode);
+}
+INLINE ir_node *new_r_Sub (ir_graph *irg, ir_node *block,
+ ir_node *op1, ir_node *op2, ir_mode *mode) {
+ return new_rd_Sub(NULL, irg, block, op1, op2, mode);
+}
+INLINE ir_node *new_r_Minus (ir_graph *irg, ir_node *block,
+ ir_node *op, ir_mode *mode) {
+ return new_rd_Minus(NULL, irg, block, op, mode);
+}
+INLINE ir_node *new_r_Mul (ir_graph *irg, ir_node *block,
+ ir_node *op1, ir_node *op2, ir_mode *mode) {
+ return new_rd_Mul(NULL, irg, block, op1, op2, mode);
+}
+INLINE ir_node *new_r_Quot (ir_graph *irg, ir_node *block,
+ ir_node *memop, ir_node *op1, ir_node *op2) {
+ return new_rd_Quot(NULL, irg, block, memop, op1, op2);
+}
+INLINE ir_node *new_r_DivMod (ir_graph *irg, ir_node *block,
+ ir_node *memop, ir_node *op1, ir_node *op2) {
+ return new_rd_DivMod(NULL, irg, block, memop, op1, op2);
+}
+INLINE ir_node *new_r_Div (ir_graph *irg, ir_node *block,
+ ir_node *memop, ir_node *op1, ir_node *op2) {
+ return new_rd_Div(NULL, irg, block, memop, op1, op2);
+}
+INLINE ir_node *new_r_Mod (ir_graph *irg, ir_node *block,
+ ir_node *memop, ir_node *op1, ir_node *op2) {
+ return new_rd_Mod(NULL, irg, block, memop, op1, op2);
+}
+INLINE ir_node *new_r_Abs (ir_graph *irg, ir_node *block,
+ ir_node *op, ir_mode *mode) {
+ return new_rd_Abs(NULL, irg, block, op, mode);
+}
+INLINE ir_node *new_r_And (ir_graph *irg, ir_node *block,
+ ir_node *op1, ir_node *op2, ir_mode *mode) {
+ return new_rd_And(NULL, irg, block, op1, op2, mode);
+}
+INLINE ir_node *new_r_Or (ir_graph *irg, ir_node *block,
+ ir_node *op1, ir_node *op2, ir_mode *mode) {
+ return new_rd_Or(NULL, irg, block, op1, op2, mode);
+}
+INLINE ir_node *new_r_Eor (ir_graph *irg, ir_node *block,
+ ir_node *op1, ir_node *op2, ir_mode *mode) {
+ return new_rd_Eor(NULL, irg, block, op1, op2, mode);
+}
+INLINE ir_node *new_r_Not (ir_graph *irg, ir_node *block,
+ ir_node *op, ir_mode *mode) {
+ return new_rd_Not(NULL, irg, block, op, mode);
+}
+INLINE ir_node *new_r_Cmp (ir_graph *irg, ir_node *block,
+ ir_node *op1, ir_node *op2) {
+ return new_rd_Cmp(NULL, irg, block, op1, op2);
+}
+INLINE ir_node *new_r_Shl (ir_graph *irg, ir_node *block,
+ ir_node *op, ir_node *k, ir_mode *mode) {
+ return new_rd_Shl(NULL, irg, block, op, k, mode);
+}
+INLINE ir_node *new_r_Shr (ir_graph *irg, ir_node *block,
+ ir_node *op, ir_node *k, ir_mode *mode) {
+ return new_rd_Shr(NULL, irg, block, op, k, mode);
+}
+INLINE ir_node *new_r_Shrs (ir_graph *irg, ir_node *block,
+ ir_node *op, ir_node *k, ir_mode *mode) {
+ return new_rd_Shrs(NULL, irg, block, op, k, mode);
+}
+INLINE ir_node *new_r_Rot (ir_graph *irg, ir_node *block,
+ ir_node *op, ir_node *k, ir_mode *mode) {
+ return new_rd_Rot(NULL, irg, block, op, k, mode);
+}
+INLINE ir_node *new_r_Conv (ir_graph *irg, ir_node *block,
+ ir_node *op, ir_mode *mode) {
+ return new_rd_Conv(NULL, irg, block, op, mode);
+}
+INLINE ir_node *new_r_Cast (ir_graph *irg, ir_node *block, ir_node *op, type *to_tp) {
+ return new_rd_Cast(NULL, irg, block, op, to_tp);
+}
+INLINE ir_node *new_r_Phi (ir_graph *irg, ir_node *block, int arity,
+ ir_node **in, ir_mode *mode) {
+ return new_rd_Phi(NULL, irg, block, arity, in, mode);
+}
+INLINE ir_node *new_r_Load (ir_graph *irg, ir_node *block,
+ ir_node *store, ir_node *adr) {
+ return new_rd_Load(NULL, irg, block, store, adr);
+}
+INLINE ir_node *new_r_Store (ir_graph *irg, ir_node *block,
+ ir_node *store, ir_node *adr, ir_node *val) {
+ return new_rd_Store(NULL, irg, block, store, adr, val);
+}
+INLINE ir_node *new_r_Alloc (ir_graph *irg, ir_node *block, ir_node *store,
+ ir_node *size, type *alloc_type, where_alloc where) {
+ return new_rd_Alloc(NULL, irg, block, store, size, alloc_type, where);
+}
+INLINE ir_node *new_r_Free (ir_graph *irg, ir_node *block, ir_node *store,
+ ir_node *ptr, ir_node *size, type *free_type) {
+ return new_rd_Free(NULL, irg, block, store, ptr, size, free_type);
+}
+INLINE ir_node *new_r_Sync (ir_graph *irg, ir_node *block, int arity, ir_node **in) {
+ return new_rd_Sync(NULL, irg, block, arity, in);
+}
+INLINE ir_node *new_r_Proj (ir_graph *irg, ir_node *block, ir_node *arg,
+ ir_mode *mode, long proj) {
+ return new_rd_Proj(NULL, irg, block, arg, mode, proj);
+}
+INLINE ir_node *new_r_defaultProj (ir_graph *irg, ir_node *block, ir_node *arg,
+ long max_proj) {
+ return new_rd_defaultProj(NULL, irg, block, arg, max_proj);
+}
+INLINE ir_node *new_r_Tuple (ir_graph *irg, ir_node *block,
+ int arity, ir_node **in) {
+ return new_rd_Tuple(NULL, irg, block, arity, in );
+}
+INLINE ir_node *new_r_Id (ir_graph *irg, ir_node *block,
+ ir_node *val, ir_mode *mode) {
+ return new_rd_Id(NULL, irg, block, val, mode);
+}
+INLINE ir_node *new_r_Bad (ir_graph *irg) {
+ return new_rd_Bad(irg);
+}
+INLINE ir_node *new_r_Confirm (ir_graph *irg, ir_node *block, ir_node *val, ir_node *bound, pn_Cmp cmp) {
+ return new_rd_Confirm (NULL, irg, block, val, bound, cmp);
+}
+INLINE ir_node *new_r_Unknown (ir_graph *irg, ir_mode *m) {
+ return new_rd_Unknown(irg, m);
+}
+INLINE ir_node *new_r_CallBegin (ir_graph *irg, ir_node *block, ir_node *callee) {
+ return new_rd_CallBegin(NULL, irg, block, callee);
+}
+INLINE ir_node *new_r_EndReg (ir_graph *irg, ir_node *block) {
+ return new_rd_EndReg(NULL, irg, block);
+}
+INLINE ir_node *new_r_EndExcept (ir_graph *irg, ir_node *block) {
+ return new_rd_EndExcept(NULL, irg, block);
+}
+INLINE ir_node *new_r_Break (ir_graph *irg, ir_node *block) {
+ return new_rd_Break(NULL, irg, block);
+}
+INLINE ir_node *new_r_Filter (ir_graph *irg, ir_node *block, ir_node *arg,
+ ir_mode *mode, long proj) {
+ return new_rd_Filter(NULL, irg, block, arg, mode, proj);
+}
+INLINE ir_node *new_r_FuncCall (ir_graph *irg, ir_node *block,
+ ir_node *callee, int arity, ir_node **in,
+ type *tp) {
+ return new_rd_FuncCall(NULL, irg, block, callee, arity, in, tp);
+}
+
+
+/** ********************/
+/** public interfaces */
+/** construction tools */
+
+/**
+ *
+ * - create a new Start node in the current block
+ *
+ * @return s - pointer to the created Start node
+ *
+ *
+ */
+ir_node *
+new_d_Start (dbg_info* db)
+{
+ ir_node *res;
+
+ res = new_ir_node (db, current_ir_graph, current_ir_graph->current_block,
+ op_Start, mode_T, 0, NULL);
+ //res->attr.start.irg = current_ir_graph;
+
+ res = optimize_node (res);
+ irn_vrfy_irg (res, current_ir_graph);
+ return res;
+}
+
+ir_node *
+new_d_End (dbg_info* db)
+{
+ ir_node *res;
+ res = new_ir_node (db, current_ir_graph, current_ir_graph->current_block,
+ op_End, mode_X, -1, NULL);
+ res = optimize_node (res);
+ irn_vrfy_irg (res, current_ir_graph);
+
+ return res;
+}
+
+/* Constructs a Block with a fixed number of predecessors.
+ Does set current_block. Can be used with automatic Phi
+ node construction. */
+ir_node *
+new_d_Block (dbg_info* db, int arity, ir_node **in)
+{
+ ir_node *res;
+ int i;
+ bool has_unknown = false;
+
+ res = new_rd_Block (db, current_ir_graph, arity, in);
+
+ /* Create and initialize array for Phi-node construction. */
+ res->attr.block.graph_arr = NEW_ARR_D (ir_node *, current_ir_graph->obst,
+ current_ir_graph->n_loc);
+ memset(res->attr.block.graph_arr, 0, sizeof(ir_node *)*current_ir_graph->n_loc);
+
+ for (i = arity-1; i >= 0; i--) if (get_irn_op(in[i]) == op_Unknown) has_unknown = true;
+
+ if (!has_unknown) res = optimize_node (res);
+ current_ir_graph->current_block = res;
+
+ irn_vrfy_irg (res, current_ir_graph);
+
+ return res;
+}
+
+/* ***********************************************************************/
+/* Methods necessary for automatic Phi node creation */
+/*
+ ir_node *phi_merge (ir_node *block, int pos, ir_mode *mode, ir_node **nin, int ins)
+ ir_node *get_r_value_internal (ir_node *block, int pos, ir_mode *mode);
+ ir_node *new_rd_Phi0 (ir_graph *irg, ir_node *block, ir_mode *mode)
+ ir_node *new_rd_Phi_in (ir_graph *irg, ir_node *block, ir_mode *mode, ir_node **in, int ins)
+
+ Call Graph: ( A ---> B == A "calls" B)
+
+ get_value mature_block
+ | |
+ | |
+ | |
+ | ---> phi_merge
+ | / / \
+ | / / \
+ \|/ / |/_ \
+ get_r_value_internal |
+ | |
+ | |
+ \|/ \|/
+ new_rd_Phi0 new_rd_Phi_in
+
+* *************************************************************************** */
+
+/* Creates a Phi node with 0 predecessors */
+static INLINE ir_node *
+new_rd_Phi0 (ir_graph *irg, ir_node *block, ir_mode *mode)
+{
+ ir_node *res;
+ res = new_ir_node (NULL, irg, block, op_Phi, mode, 0, NULL);
+ irn_vrfy_irg (res, irg);
+ return res;
+}
+
+/* There are two implementations of the Phi node construction. The first
+ is faster, but does not work for blocks with more than 2 predecessors.
+ The second works always but is slower and causes more unnecessary Phi
+ nodes.
+ Select the implementations by the following preprocessor flag set in
+ common/common.h: */
+#if USE_FAST_PHI_CONSTRUCTION
+
+/* This is a stack used for allocating and deallocating nodes in
+ new_rd_Phi_in. The original implementation used the obstack
+ to model this stack, now it is explicit. This reduces side effects.
+*/
+#if USE_EXPLICIT_PHI_IN_STACK
+INLINE Phi_in_stack *
+new_Phi_in_stack(void) {
+ Phi_in_stack *res;
+
+ res = (Phi_in_stack *) malloc ( sizeof (Phi_in_stack));
+
+ res->stack = NEW_ARR_F (ir_node *, 1);
+ res->pos = 0;
+
+ return res;
+}
+
+INLINE void
+free_Phi_in_stack(Phi_in_stack *s) {
+ DEL_ARR_F(s->stack);
+ free(s);
+}
+static INLINE void
+free_to_Phi_in_stack(ir_node *phi) {
+ assert(get_irn_opcode(phi) == iro_Phi);
+
+ if (ARR_LEN(current_ir_graph->Phi_in_stack->stack) ==
+ current_ir_graph->Phi_in_stack->pos)
+ ARR_APP1 (ir_node *, current_ir_graph->Phi_in_stack->stack, phi);
+ else
+ current_ir_graph->Phi_in_stack->stack[current_ir_graph->Phi_in_stack->pos] = phi;
+
+ (current_ir_graph->Phi_in_stack->pos)++;
+}
+
+static INLINE ir_node *
+alloc_or_pop_from_Phi_in_stack(ir_graph *irg, ir_node *block, ir_mode *mode,
+ int arity, ir_node **in) {
+ ir_node *res;
+ ir_node **stack = current_ir_graph->Phi_in_stack->stack;
+ int pos = current_ir_graph->Phi_in_stack->pos;
+
+
+ if (pos == 0) {
+ /* We need to allocate a new node */
+ res = new_ir_node (db, irg, block, op_Phi, mode, arity, in);
+ res->attr.phi_backedge = new_backedge_arr(irg->obst, arity);
+ } else {
+ /* reuse the old node and initialize it again. */
+ res = stack[pos-1];
+
+ assert (res->kind == k_ir_node);
+ assert (res->op == op_Phi);
+ res->mode = mode;
+ res->visited = 0;
+ res->link = NULL;
+ assert (arity >= 0);
+ /* ???!!! How to free the old in array?? Not at all: on obstack ?!! */
+ res->in = NEW_ARR_D (ir_node *, irg->obst, (arity+1));
+ res->in[0] = block;
+ memcpy (&res->in[1], in, sizeof (ir_node *) * arity);
+
+ (current_ir_graph->Phi_in_stack->pos)--;
+ }
+ return res;
+}
+#endif /* USE_EXPLICIT_PHI_IN_STACK */
+
+/* Creates a Phi node with a given, fixed array **in of predecessors.
+ If the Phi node is unnecessary, as the same value reaches the block
+ through all control flow paths, it is eliminated and the value
+ returned directly. This constructor is only intended for use in
+ the automatic Phi node generation triggered by get_value or mature.
+ The implementation is quite tricky and depends on the fact, that
+ the nodes are allocated on a stack:
+ The in array contains predecessors and NULLs. The NULLs appear,
+ if get_r_value_internal, that computed the predecessors, reached
+ the same block on two paths. In this case the same value reaches
+ this block on both paths, there is no definition in between. We need
+ not allocate a Phi where these path's merge, but we have to communicate
+ this fact to the caller. This happens by returning a pointer to the
+ node the caller _will_ allocate. (Yes, we predict the address. We can
+ do so because the nodes are allocated on the obstack.) The caller then
+ finds a pointer to itself and, when this routine is called again,
+ eliminates itself.
+ */
+static INLINE ir_node *
+new_rd_Phi_in (ir_graph *irg, ir_node *block, ir_mode *mode,
+ ir_node **in, int ins)
+{
+ int i;
+ ir_node *res, *known;
+
+ /* allocate a new node on the obstack.
+ This can return a node to which some of the pointers in the in-array
+ already point.
+ Attention: the constructor copies the in array, i.e., the later changes
+ to the array in this routine do not affect the constructed node! If
+ the in array contains NULLs, there will be missing predecessors in the
+ returned node.
+ Is this a possible internal state of the Phi node generation? */
+#if USE_EXPLICIT_PHI_IN_STACK
+ res = known = alloc_or_pop_from_Phi_in_stack(irg, block, mode, ins, in);
+#else
+ res = known = new_ir_node (NULL, irg, block, op_Phi, mode, ins, in);
+ res->attr.phi_backedge = new_backedge_arr(irg->obst, ins);
+#endif
+ /* The in-array can contain NULLs. These were returned by
+ get_r_value_internal if it reached the same block/definition on a
+ second path.
+ The NULLs are replaced by the node itself to simplify the test in the
+ next loop. */
+ for (i=0; i < ins; ++i)
+ if (in[i] == NULL) in[i] = res;
+
+ /* This loop checks whether the Phi has more than one predecessor.
+ If so, it is a real Phi node and we break the loop. Else the
+ Phi node merges the same definition on several paths and therefore
+ is not needed. */
+ for (i=0; i < ins; ++i)
+ {
+ if (in[i]==res || in[i]==known) continue;
+
+ if (known==res)
+ known = in[i];
+ else
+ break;
+ }
+
+ /* i==ins: there is at most one predecessor, we don't need a phi node. */
+ if (i==ins) {
+#if USE_EXPLICIT_PHI_IN_STACK
+ free_to_Phi_in_stack(res);
+#else
+ obstack_free (current_ir_graph->obst, res);
+#endif
+ res = known;
+ } else {
+ res = optimize_node (res);
+ irn_vrfy_irg (res, irg);
+ }
+
+ /* return the pointer to the Phi node. This node might be deallocated! */
+ return res;
+}
+
+static ir_node *
+get_r_value_internal (ir_node *block, int pos, ir_mode *mode);
+
+/**
+ allocates and returns this node. The routine called to allocate the
+ node might optimize it away and return a real value, or even a pointer
+ to a deallocated Phi node on top of the obstack!
+ This function is called with an in-array of proper size. **/
+static ir_node *
+phi_merge (ir_node *block, int pos, ir_mode *mode, ir_node **nin, int ins)
+{
+ ir_node *prevBlock, *res;
+ int i;
+
+ /* This loop goes to all predecessor blocks of the block the Phi node is in
+ and there finds the operands of the Phi node by calling
+ get_r_value_internal. */
+ for (i = 1; i <= ins; ++i) {
+ assert (block->in[i]);
+ prevBlock = block->in[i]->in[0]; /* go past control flow op to prev block */
+ assert (prevBlock);
+ nin[i-1] = get_r_value_internal (prevBlock, pos, mode);
+ }
+
+ /* After collecting all predecessors into the array nin a new Phi node
+ with these predecessors is created. This constructor contains an
+ optimization: If all predecessors of the Phi node are identical it
+ returns the only operand instead of a new Phi node. If the value
+ passes two different control flow edges without being defined, and
+ this is the second path treated, a pointer to the node that will be
+ allocated for the first path (recursion) is returned. We already
+ know the address of this node, as it is the next node to be allocated
+ and will be placed on top of the obstack. (The obstack is a _stack_!) */
+ res = new_rd_Phi_in (current_ir_graph, block, mode, nin, ins);
+
+ /* Now we now the value for "pos" and can enter it in the array with
+ all known local variables. Attention: this might be a pointer to
+ a node, that later will be allocated!!! See new_rd_Phi_in.
+ If this is called in mature, after some set_value in the same block,
+ the proper value must not be overwritten:
+ The call order
+ get_value (makes Phi0, put's it into graph_arr)
+ set_value (overwrites Phi0 in graph_arr)
+ mature_block (upgrades Phi0, puts it again into graph_arr, overwriting
+ the proper value.)
+ fails. */
+ if (!block->attr.block.graph_arr[pos]) {
+ block->attr.block.graph_arr[pos] = res;
+ } else {
+ /* printf(" value already computed by %s\n",
+ get_id_str(block->attr.block.graph_arr[pos]->op->name)); */
+ }
+
+ return res;
+}
+
+/* This function returns the last definition of a variable. In case
+ this variable was last defined in a previous block, Phi nodes are
+ inserted. If the part of the firm graph containing the definition
+ is not yet constructed, a dummy Phi node is returned. */
+static ir_node *
+get_r_value_internal (ir_node *block, int pos, ir_mode *mode)
+{
+ ir_node *res;
+ /* There are 4 cases to treat.
+
+ 1. The block is not mature and we visit it the first time. We can not
+ create a proper Phi node, therefore a Phi0, i.e., a Phi without
+ predecessors is returned. This node is added to the linked list (field
+ "link") of the containing block to be completed when this block is
+ matured. (Completion will add a new Phi and turn the Phi0 into an Id
+ node.)
+
+ 2. The value is already known in this block, graph_arr[pos] is set and we
+ visit the block the first time. We can return the value without
+ creating any new nodes.
+
+ 3. The block is mature and we visit it the first time. A Phi node needs
+ to be created (phi_merge). If the Phi is not needed, as all it's
+ operands are the same value reaching the block through different
+ paths, it's optimized away and the value itself is returned.
+
+ 4. The block is mature, and we visit it the second time. Now two
+ subcases are possible:
+ * The value was computed completely the last time we were here. This
+ is the case if there is no loop. We can return the proper value.
+ * The recursion that visited this node and set the flag did not
+ return yet. We are computing a value in a loop and need to
+ break the recursion without knowing the result yet.
+ @@@ strange case. Straight forward we would create a Phi before
+ starting the computation of it's predecessors. In this case we will
+ find a Phi here in any case. The problem is that this implementation
+ only creates a Phi after computing the predecessors, so that it is
+ hard to compute self references of this Phi. @@@
+ There is no simple check for the second subcase. Therefore we check
+ for a second visit and treat all such cases as the second subcase.
+ Anyways, the basic situation is the same: we reached a block
+ on two paths without finding a definition of the value: No Phi
+ nodes are needed on both paths.
+ We return this information "Two paths, no Phi needed" by a very tricky
+ implementation that relies on the fact that an obstack is a stack and
+ will return a node with the same address on different allocations.
+ Look also at phi_merge and new_rd_phi_in to understand this.
+ @@@ Unfortunately this does not work, see testprogram
+ three_cfpred_example.
+
+ */
+
+ /* case 4 -- already visited. */
+ if (get_irn_visited(block) == get_irg_visited(current_ir_graph)) return NULL;
+
+ /* visited the first time */
+ set_irn_visited(block, get_irg_visited(current_ir_graph));
+
+ /* Get the local valid value */
+ res = block->attr.block.graph_arr[pos];
+
+ /* case 2 -- If the value is actually computed, return it. */
+ if (res) { return res;};
+
+ if (block->attr.block.matured) { /* case 3 */
+
+ /* The Phi has the same amount of ins as the corresponding block. */
+ int ins = get_irn_arity(block);
+ ir_node **nin;
+ NEW_ARR_A (ir_node *, nin, ins);
+
+ /* Phi merge collects the predecessors and then creates a node. */
+ res = phi_merge (block, pos, mode, nin, ins);
+
+ } else { /* case 1 */
+ /* The block is not mature, we don't know how many in's are needed. A Phi
+ with zero predecessors is created. Such a Phi node is called Phi0
+ node. (There is also an obsolete Phi0 opcode.) The Phi0 is then added
+ to the list of Phi0 nodes in this block to be matured by mature_block
+ later.
+ The Phi0 has to remember the pos of it's internal value. If the real
+ Phi is computed, pos is used to update the array with the local
+ values. */
+
+ res = new_rd_Phi0 (current_ir_graph, block, mode);
+ res->attr.phi0_pos = pos;
+ res->link = block->link;
+ block->link = res;
+ }
+
+ /* If we get here, the frontend missed a use-before-definition error */
+ if (!res) {
+ /* Error Message */
+ printf("Error: no value set. Use of undefined variable. Initializing to zero.\n");
+ assert (mode->code >= irm_F && mode->code <= irm_P);
+ res = new_rd_Const (NULL, current_ir_graph, block, mode,
+ tarval_mode_null[mode->code]);
+ }
+
+ /* The local valid value is available now. */
+ block->attr.block.graph_arr[pos] = res;
+
+ return res;
+}
+
+#else /* if 0 */
+
+/**
+ it starts the recursion. This causes an Id at the entry of
+ every block that has no definition of the value! **/
+
+#if USE_EXPLICIT_PHI_IN_STACK
+/* Just dummies */
+INLINE Phi_in_stack * new_Phi_in_stack() { return NULL; }
+INLINE void free_Phi_in_stack(Phi_in_stack *s) { }
+#endif
+
+static INLINE ir_node *
+new_rd_Phi_in (ir_graph *irg, ir_node *block, ir_mode *mode,
+ ir_node **in, int ins)
+{
+ int i;
+ ir_node *res, *known;
+
+ /* Allocate a new node on the obstack. The allocation copies the in
+ array. */
+ res = new_ir_node (NULL, irg, block, op_Phi, mode, ins, in);
+ res->attr.phi_backedge = new_backedge_arr(irg->obst, ins);
+
+ /* This loop checks whether the Phi has more than one predecessor.
+ If so, it is a real Phi node and we break the loop. Else the
+ Phi node merges the same definition on several paths and therefore
+ is not needed. Don't consider Bad nodes! */
+ known = res;
+ for (i=0; i < ins; ++i)
+ {
+ assert(in[i]);
+
+ if (in[i]==res || in[i]==known || is_Bad(in[i])) continue;
+
+ if (known==res)
+ known = in[i];
+ else
+ break;
+ }
+
+ /* i==ins: there is at most one predecessor, we don't need a phi node. */
+ if (i==ins) {
+ if (res != known) {
+ obstack_free (current_ir_graph->obst, res);
+ res = known;
+ } else {
+ /* A undefined value, e.g., in unreachable code. */
+ res = new_Bad();
+ }
+ } else {
+ res = optimize_node (res);
+ irn_vrfy_irg (res, irg);
+ /* Memory Phis in endless loops must be kept alive.
+ As we can't distinguish these easily we keep all of the alive. */
+ if ((res->op == op_Phi) && (mode == mode_M))
+ add_End_keepalive(irg->end, res);
+ }