flags fixup phase

[r15763]

ir/be/beflags.c

+/*
+ * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
+ *
+ * This file is part of libFirm.
+ *
+ * This file may be distributed and/or modified under the terms of the
+ * GNU General Public License version 2 as published by the Free Software
+ * Foundation and appearing in the file LICENSE.GPL included in the
+ * packaging of this file.
+ *
+ * Licensees holding valid libFirm Professional Edition licenses may use
+ * this file in accordance with the libFirm Commercial License.
+ * Agreement provided with the Software.
+ *
+ * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+ * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE.
+ */
+
+/**
+ * @file
+ * @brief       modifies schedule so flags dependencies are respected.
+ * @author      Matthias Braun, Christoph Mallon
+ * @version     $Id: besched.h 14693 2007-06-21 15:35:49Z beck $
+ */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "irgwalk.h"
+#include "irnode_t.h"
+#include "irtools.h"
+#include "ircons.h"
+#include "iredges_t.h"
+#include "irprintf.h"
+#include "error.h"
+
+#include "beflags.h"
+#include "bearch_t.h"
+#include "beirg_t.h"
+#include "besched_t.h"
+
+static const arch_env_t            *arch_env   = NULL;
+static const arch_register_class_t *flag_class = NULL;
+static const arch_register_t       *flags_reg  = NULL;
+static func_rematerialize           remat      = NULL;
+
+static ir_node *default_remat(ir_node *node, ir_node *after)
+{
+	ir_node *copy  = exact_copy(node);
+	sched_add_after(after, copy);
+
+	return copy;
+}
+
+/**
+ * tests wether we can legally move node node after node after
+ * (only works for nodes in same block)
+ */
+static int can_move(ir_node *node, ir_node *after)
+{
+	const ir_edge_t *edge;
+	assert(get_nodes_block(node) == get_nodes_block(after));
+
+	/* TODO respect dep edges */
+	assert(get_irn_n_edges_kind(node, EDGE_KIND_DEP) == 0);
+
+	/** all users have to be after the after node */
+	foreach_out_edge(node, edge) {
+		ir_node *out = get_edge_src_irn(edge);
+		if(is_Proj(out)) {
+			const ir_edge_t *edge2;
+			assert(get_irn_n_edges_kind(out, EDGE_KIND_DEP) == 0);
+			foreach_out_edge(out, edge2) {
+				ir_node *out2 = get_edge_src_irn(edge2);
+				/* phi represents a usage at block end */
+				if(is_Phi(out2))
+					continue;
+				if(sched_get_time_step(out2) <= sched_get_time_step(after)) {
+					return 0;
+				}
+			}
+		} else {
+			/* phi represents a usage at block end */
+			if(is_Phi(out))
+				continue;
+			if(sched_get_time_step(out) <= sched_get_time_step(after)) {
+				return 0;
+			}
+		}
+	}
+
+	ir_fprintf(stderr, "Can move node %+F after node %+F\n", node, after);
+	return 1;
+}
+
+static void rematerialize_or_move(ir_node *flags_needed, ir_node *node,
+                                  ir_node *flag_consumers, int pn)
+{
+	ir_node *n;
+	ir_node *copy;
+	ir_node *value;
+
+	if(can_move(flags_needed, node)) {
+		/* move it */
+		sched_remove(flags_needed);
+		sched_add_after(node, flags_needed);
+		return;
+	}
+
+	copy = remat(flags_needed, node);
+
+	if(get_irn_mode(copy) == mode_T) {
+		ir_node *block = get_nodes_block(copy);
+		ir_mode *mode  = flag_class->mode;
+		value = new_rd_Proj(NULL, current_ir_graph, block,
+							copy, mode, pn);
+	} else {
+		value = copy;
+	}
+
+	n = flag_consumers;
+	do {
+		int i;
+		int arity = get_irn_arity(n);
+		for(i = 0; i < arity; ++i) {
+			ir_node *in = get_irn_n(n, i);
+			in = skip_Proj(in);
+			if(in == flags_needed) {
+				set_irn_n(n, i, value);
+				break;
+			}
+		}
+		n = get_irn_link(n);
+	} while(n != NULL);
+}
+
+static void fix_flags_walker(ir_node *block, void *env)
+{
+	ir_node *node;
+	ir_node *flags_needed   = NULL;
+	ir_node *flag_consumers = NULL;
+	int      pn;
+	(void) env;
+
+	sched_foreach_reverse(block, node) {
+		int i, arity;
+		ir_node *new_flags_needed = NULL;
+
+		if(node == flags_needed) {
+			/* all ok */
+			flags_needed   = NULL;
+			flag_consumers = NULL;
+		}
+
+		/* test wether node destroys the flags */
+		if(flags_needed != NULL && arch_irn_is(arch_env, node, modify_flags)) {
+			/* rematerialize */
+			rematerialize_or_move(flags_needed, node, flag_consumers, pn);
+			flags_needed   = NULL;
+			flag_consumers = NULL;
+		}
+
+		/* test wether the current node needs flags */
+		arity = get_irn_arity(node);
+		for(i = 0; i < arity; ++i) {
+			//ir_node *in = get_irn_n(node, i);
+			const arch_register_class_t *cls
+				= arch_get_irn_reg_class(arch_env, node, i);
+			if(cls == flag_class) {
+				assert(new_flags_needed == NULL);
+				new_flags_needed = get_irn_n(node, i);
+			}
+		}
+
+		if(new_flags_needed == NULL)
+			continue;
+
+		if(new_flags_needed != flags_needed) {
+			if(flags_needed != NULL) {
+				/* rematerialize node */
+				rematerialize_or_move(flags_needed, node, flag_consumers, pn);
+				flags_needed    = NULL;
+				flag_consumers = NULL;
+			}
+
+			if(get_nodes_block(new_flags_needed) != block) {
+				panic("remat across blocks not implemented yet");
+				flags_needed   = NULL;
+				flag_consumers = NULL;
+			} else {
+				flags_needed = new_flags_needed;
+				arch_set_irn_register(arch_env, flags_needed, flags_reg);
+				if(is_Proj(flags_needed)) {
+					pn           = get_Proj_proj(flags_needed);
+					flags_needed = get_Proj_pred(flags_needed);
+				}
+				flag_consumers = node;
+				set_irn_link(flag_consumers, NULL);
+				assert(arch_irn_is(arch_env, flags_needed, rematerializable));
+			}
+		} else {
+			/* link all consumers in a list */
+			set_irn_link(flag_consumers, node);
+			flag_consumers = node;
+		}
+	}
+
+	assert(flags_needed   == NULL);
+	assert(flag_consumers == NULL);
+}
+
+void be_sched_fix_flags(be_irg_t *birg, const arch_register_class_t *flag_cls,
+                        func_rematerialize remat_func)
+{
+	ir_graph *irg = be_get_birg_irg(birg);
+
+	arch_env   = be_get_birg_arch_env(birg);
+	flag_class = flag_cls;
+	flags_reg  = & flag_class->regs[0];
+	remat      = remat_func;
+	if(remat == NULL)
+		remat = &default_remat;
+
+	set_using_irn_link(irg);
+	irg_block_walk_graph(irg, fix_flags_walker, NULL, NULL);
+	clear_using_irn_link(irg);
+}

ir/be/beflags.h

+/*
+ * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
+ *
+ * This file is part of libFirm.
+ *
+ * This file may be distributed and/or modified under the terms of the
+ * GNU General Public License version 2 as published by the Free Software
+ * Foundation and appearing in the file LICENSE.GPL included in the
+ * packaging of this file.
+ *
+ * Licensees holding valid libFirm Professional Edition licenses may use
+ * this file in accordance with the libFirm Commercial License.
+ * Agreement provided with the Software.
+ *
+ * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+ * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE.
+ */
+
+/**
+ * @file
+ * @brief       modifies schedule so flags dependencies are respected.
+ * @author      Matthias Braun, Christoph Mallon
+ * @version     $Id: besched.h 14693 2007-06-21 15:35:49Z beck $
+ */
+#ifndef FIRM_BE_BEFLAGS_H
+#define FIRM_BE_BEFLAGS_H
+
+#include "bearch.h"
+#include "beirg.h"
+
+typedef ir_node * (*func_rematerialize) (ir_node *node, ir_node *after);
+
+/**
+ * Walks the schedule and ensures that flags aren't destroyed between producer
+ * and consumer of flags. It does so by moving down/rematerialising of the
+ * nodes. This does not work across blocks.
+ */
+void be_sched_fix_flags(be_irg_t *birg, const arch_register_class_t *flag_cls,
+                        func_rematerialize remat_func);
+
+#endif