- add more passes
[libfirm] / ir / opt / ldst2.c
index 32e9297..0c72988 100644 (file)
@@ -1,5 +1,33 @@
-#include <stdint.h>
-#include "array.h"
+/*
+ * Copyright (C) 1995-2008 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   parallelizing Load/Store optimisation
+ * @author  Christoph Mallon
+ * @version $Id: $
+ */
+#include "config.h"
+
+#include "iroptimize.h"
+
+#include "array_t.h"
 #include "debug.h"
 #include "ircons.h"
 #include "irgraph.h"
 #include "irmemory.h"
 #include "irnode.h"
 #include "irnodeset.h"
-#include "ldst2.h"
 #include "obst.h"
-#include "return.h"
-
+#include "irdump.h"
+#include "irflag_t.h"
+#include "irprintf.h"
+#include "irtools.h"
 
+#if +0
 #define OPTIMISE_LOAD_AFTER_LOAD
 
 
@@ -53,7 +83,7 @@ static void CollectAddresses(ir_graph* irg)
        irg_walk_graph(irg, AddressCollector, NULL, &addrs_set);
 
        count_addrs = ir_nodeset_size(&addrs_set);
-       DB((dbg, LEVEL_1, "===> %+F uses %u unique addresses\n", irg, (uint)count_addrs));
+       DB((dbg, LEVEL_1, "===> %+F uses %u unique addresses\n", irg, (unsigned int)count_addrs));
        if (count_addrs != 0) {
                ir_nodeset_iterator_t addr_iter;
                size_t i;
@@ -63,7 +93,7 @@ static void CollectAddresses(ir_graph* irg)
                for (i = 0; i < count_addrs; i++) {
                        ir_node* addr = ir_nodeset_iterator_next(&addr_iter);
                        assert(addr != NULL);
-                       set_irn_link(addr, (void*)(uintptr_t)i);
+                       set_irn_link(addr, (void *)i);
                        addrs[i] = addr;
                        DB((dbg, LEVEL_2, "===> Collected unique symbolic address %+F\n", addr));
                }
@@ -75,6 +105,7 @@ static void AliasSetAdder(ir_node* block, void* env)
 {
        ir_nodeset_t* alias_set;
        size_t i;
+       (void) env;
 
        alias_set = NEW_ARR_D(ir_nodeset_t, &obst, count_addrs);
        for (i = 0; i < count_addrs; i++) {
@@ -105,6 +136,7 @@ static void AliasSetDestroyer(ir_node* block, void* env)
 {
        ir_nodeset_t* alias_set = get_irn_link(block);
        size_t i;
+       (void) env;
 
        for (i = 0; i < count_addrs; i++) {
                ir_nodeset_destroy(&alias_set[i]);
@@ -124,7 +156,7 @@ static ir_alias_relation AliasTest(ir_graph* irg, ir_node* addr, ir_mode* mode,
        } else if (is_Store(other)) {
                other_addr = get_Store_ptr(other);
        } else {
-               return may_alias;
+               return ir_may_alias;
        }
 
        other_mode = get_irn_mode(other);
@@ -132,51 +164,90 @@ static ir_alias_relation AliasTest(ir_graph* irg, ir_node* addr, ir_mode* mode,
 }
 
 
-static int WalkMem(ir_graph* irg, ir_node* node, ir_node* last_block);
+static int in_cmp(void const* va, void const* vb)
+{
+       ir_node const* const a = *(ir_node const*const*)va;
+       ir_node const* const b = *(ir_node const*const*)vb;
+       return get_irn_idx(a) - get_irn_idx(b);
+}
 
 
-static void WalkMemPhi(ir_graph* irg, ir_node* block, ir_node* phi)
+static ir_node* GenerateSync(ir_graph* irg, ir_node* block, ir_nodeset_t* after_set)
 {
-       size_t n = get_Phi_n_preds(phi);
-       size_t i;
-       size_t j;
-       ir_node** in;
-       ir_nodeset_t* thissets;
+       size_t set_size = ir_nodeset_size(after_set);
+       ir_nodeset_iterator_t iter;
 
-       for (i = 0; i < n; i++) {
-               WalkMem(irg, get_Phi_pred(phi, i), block);
+       assert(set_size != 0);
+
+       ir_nodeset_iterator_init(&iter, after_set);
+       if (set_size == 1) {
+               return ir_nodeset_iterator_next(&iter);
+       } else {
+               ir_node** in;
+               size_t i;
+
+               NEW_ARR_A(ir_node*, in, set_size);
+               for (i = 0; i < set_size; i++) {
+                       in[i] = ir_nodeset_iterator_next(&iter);
+               }
+               qsort(in, set_size, sizeof(*in), in_cmp);
+               return new_r_Sync(irg, block, set_size, in);
        }
+}
+
+
+static ir_node** unfinished_phis;
+
+
+static void PlaceMemPhis(ir_graph* irg, ir_node* block, ir_node* phi)
+{
+       int unfinished = 0;
+       size_t block_n_preds = get_Block_n_cfgpreds(block);
+       ir_nodeset_t* thissets;
+       ir_node** in;
+       size_t i;
+       size_t j;
 
        thissets = get_irn_link(block);
-       NEW_ARR_A(ir_node*, in, n);
+       NEW_ARR_A(ir_node*, in, block_n_preds);
        for (j = 0; j < count_addrs; j++) {
                ir_node* new_phi;
 
-               for (i = 0; i < n; i++) {
-                       ir_nodeset_t* predsets = get_irn_link(get_nodes_block(get_Phi_pred(phi, i)));
-                       size_t size = ir_nodeset_size(&predsets[j]);
-                       ir_nodeset_iterator_t iter;
+               for (i = 0; i < block_n_preds; i++) {
+                       ir_node* pred_block = get_nodes_block(get_Phi_pred(phi, i)); // TODO get_Block_cfgpred_block(block, i);
+                       ir_nodeset_t* predsets = get_irn_link(pred_block);
+                       size_t predset_size = ir_nodeset_size(&predsets[j]);
 
-                       ir_nodeset_iterator_init(&iter, &predsets[j]);
-                       if (size == 0) {
-                               UNIMPLEMENTED
-                       } else if (size == 1) {
-                               in[i] = ir_nodeset_iterator_next(&iter);
+                       if (predset_size == 0) {
+                               in[i] = new_r_Unknown(irg, mode_M);
+                               unfinished = 1;
                        } else {
-                               ir_node** sync_in;
-                               size_t k;
-
-                               NEW_ARR_A(ir_node*, sync_in, size);
-                               for (k = 0; k < size; k++) {
-                                       sync_in[k] = ir_nodeset_iterator_next(&iter);
-                               }
-                               in[i] = new_r_Sync(irg, get_Block_cfgpred_block(block, i), size, sync_in);
+                               in[i] = GenerateSync(irg, pred_block, &predsets[j]);
                        }
                }
-               new_phi = new_r_Phi(irg, block, n, in, mode_M);
+               new_phi = new_r_Phi(irg, block, block_n_preds, in, mode_M);
+               if (unfinished) {
+                       set_irn_link(new_phi, unfinished_phis[j]);
+                       unfinished_phis[j] = new_phi;
+               }
                ir_nodeset_insert(&thissets[j], new_phi);
        }
+}
+
+
+static int WalkMem(ir_graph* irg, ir_node* node, ir_node* last_block);
+
+
+static void WalkMemPhi(ir_graph* irg, ir_node* block, ir_node* phi)
+{
+       size_t n = get_Phi_n_preds(phi);
+       size_t i;
+
+       for (i = 0; i < n; i++) {
+               WalkMem(irg, get_Phi_pred(phi, i), block);
+       }
 
+       PlaceMemPhis(irg, block, phi);
        exchange(phi, new_Bad());
 }
 
@@ -184,7 +255,7 @@ static void WalkMemPhi(ir_graph* irg, ir_node* block, ir_node* phi)
 static void PlaceLoad(ir_graph* irg, ir_node* block, ir_node* load, ir_node* memory)
 {
        ir_node* addr = get_Load_ptr(load);
-       size_t addr_idx = (size_t)(uintptr_t)get_irn_link(addr);
+       size_t addr_idx = (size_t)get_irn_link(addr);
        ir_nodeset_t* interfere_sets = get_irn_link(block);
        ir_nodeset_t* interfere_set = &interfere_sets[addr_idx];
        size_t size = ir_nodeset_size(interfere_set);
@@ -195,27 +266,18 @@ static void PlaceLoad(ir_graph* irg, ir_node* block, ir_node* load, ir_node* mem
        ir_nodeset_iterator_init(&interfere_iter, interfere_set);
        if (size == 1) {
                ir_node* after = ir_nodeset_iterator_next(&interfere_iter);
-               if (is_Proj(after)) {
-                       ir_node* pred = get_Proj_pred(after);
-                       if (is_Load(pred)) {
-#ifdef OPTIMISE_LOAD_AFTER_LOAD
-                               if (get_Load_ptr(pred) == addr && get_Load_mode(pred) == get_Load_mode(load)) {
-                                       exchange(load, pred);
-                                       return;
-                               }
-#endif
-                               after = get_Load_mem(pred);
-                       }
-               }
+               assert(!is_Proj(after) || !is_Load(get_Proj_pred(after)));
                DB((dbg, LEVEL_3, "===> %+F must be executed after %+F\n", load, after));
                set_Load_mem(load, after);
        } else {
                ir_node** after_set;
-               ir_node* sync;
+               ir_node* after;
+               ir_node* mem;
+               size_t i;
 
                NEW_ARR_A(ir_node*, after_set, size);
-               for (i = 0; i < size; i++) {
-                       ir_node* mem = ir_nodeset_iterator_next(&interfere_iter);
+               i = 0;
+               while ((mem = ir_nodeset_iterator_next(&interfere_iter)) != NULL) {
                        if (is_Proj(mem)) {
                                ir_node* pred = get_Proj_pred(mem);
                                if (is_Load(pred)) {
@@ -225,13 +287,19 @@ static void PlaceLoad(ir_graph* irg, ir_node* block, ir_node* load, ir_node* mem
                                                return;
                                        }
 #endif
-                                       mem = get_Load_mem(pred);
+                                       continue;
                                }
                        }
-                       after_set[i] = mem;
-                       sync = new_r_Sync(irg, block, size, after_set);
+                       DB((dbg, LEVEL_3, "===> %+F must be executed after %+F\n", load, mem));
+                       after_set[i++] = mem;
                }
-               set_Load_mem(load, sync);
+               assert(i != 0);
+               if (i == 1) {
+                       after = after_set[0];
+               } else {
+                       after = new_r_Sync(irg, block, i, after_set);
+               }
+               set_Load_mem(load, after);
        }
 
        for (i = 0; i < count_addrs; i++) {
@@ -239,23 +307,13 @@ static void PlaceLoad(ir_graph* irg, ir_node* block, ir_node* load, ir_node* mem
                ir_node* other_addr = addrs[i];
                ir_mode* other_mode = mode; // XXX second mode is nonsense
                ir_alias_relation rel = get_alias_relation(irg, addr, mode, other_addr, other_mode);
-               ir_node* other_node;
 
                DB((dbg, LEVEL_3, "===> Testing for alias between %+F and %+F. Relation is %d\n", addr, other_addr, rel));
-               if (rel == no_alias) {
+               if (rel == ir_no_alias) {
                        continue;
                }
                DB((dbg, LEVEL_3, "===> %+F potentially aliases address %+F\n", load, other_addr));
 
-               ir_nodeset_iterator_init(&interfere_iter, &interfere_sets[i]);
-               while ((other_node = ir_nodeset_iterator_next(&interfere_iter)) != NULL) {
-                       if (is_Proj(other_node) && is_Load(get_Proj_pred(other_node))) continue;
-                       if (AliasTest(irg, addr, mode, other_node) != no_alias) {
-                               DB((dbg, LEVEL_3, "===> Removing %+F from execute-after set of %+F due to %+F\n", other_node, addrs[i], load));
-                               ir_nodeset_remove_iterator(&interfere_sets[i], &interfere_iter);
-                       }
-               }
-
                ir_nodeset_insert(&interfere_sets[i], memory);
        }
 }
@@ -264,32 +322,17 @@ static void PlaceLoad(ir_graph* irg, ir_node* block, ir_node* load, ir_node* mem
 static void PlaceStore(ir_graph* irg, ir_node* block, ir_node* store, ir_node* memory)
 {
        ir_node* addr = get_Store_ptr(store);
-       size_t addr_idx = (size_t)(uintptr_t)get_irn_link(addr);
+       size_t addr_idx = (size_t)get_irn_link(addr);
        ir_nodeset_t* interfere_sets = get_irn_link(block);
        ir_nodeset_t* interfere_set = &interfere_sets[addr_idx];
-       size_t size = ir_nodeset_size(interfere_set);
-       ir_nodeset_iterator_t interfere_iter;
+       ir_node* after;
        size_t i;
 
-       assert(size > 0);
-       ir_nodeset_iterator_init(&interfere_iter, interfere_set);
-       if (size == 1) {
-               ir_node* after = ir_nodeset_iterator_next(&interfere_iter);
-               DB((dbg, LEVEL_3, "===> %+F must be executed after %+F\n", store, after));
-               set_Store_mem(store, after);
-       } else {
-               ir_node** after_set;
-               ir_node* sync;
-
-               NEW_ARR_A(ir_node*, after_set, size);
-               for (i = 0; i < size; i++) {
-                       after_set[i] = ir_nodeset_iterator_next(&interfere_iter);
-                       sync = new_r_Sync(irg, block, size, after_set);
-               }
-               set_Store_mem(store, sync);
-       }
+       after = GenerateSync(irg, block, interfere_set);
+       set_Store_mem(store, after);
 
        for (i = 0; i < count_addrs; i++) {
+               ir_nodeset_iterator_t interfere_iter;
                ir_mode* mode = get_irn_mode(get_Store_value(store));
                ir_node* other_addr = addrs[i];
                ir_mode* other_mode = mode; // XXX second mode is nonsense
@@ -297,14 +340,14 @@ static void PlaceStore(ir_graph* irg, ir_node* block, ir_node* store, ir_node* m
                ir_node* other_node;
 
                DB((dbg, LEVEL_3, "===> Testing for alias between %+F and %+F. Relation is %d\n", addr, other_addr, rel));
-               if (rel == no_alias) {
+               if (rel == ir_no_alias) {
                        continue;
                }
                DB((dbg, LEVEL_3, "===> %+F potentially aliases address %+F\n", store, other_addr));
 
                ir_nodeset_iterator_init(&interfere_iter, &interfere_sets[i]);
                while ((other_node = ir_nodeset_iterator_next(&interfere_iter)) != NULL) {
-                       if (AliasTest(irg, addr, mode, other_node) != no_alias) {
+                       if (AliasTest(irg, addr, mode, other_node) != ir_no_alias) {
                                DB((dbg, LEVEL_3, "===> Removing %+F from execute-after set of %+F due to %+F\n", other_node, addrs[i], store));
                                ir_nodeset_remove_iterator(&interfere_sets[i], &interfere_iter);
                        }
@@ -324,8 +367,9 @@ static int WalkMem(ir_graph* irg, ir_node* node, ir_node* last_block)
        ir_nodeset_t* addr_sets;
 
        if (block != last_block) {
+               DB((dbg, LEVEL_3, "===> Changing block from %+F to %+F\n", last_block, block));
                block_change = 1;
-               if (Block_not_block_visited(block)) {
+               if (!Block_block_visited(block)) {
                        mark_Block_block_visited(block);
                } else {
                        DB((dbg, LEVEL_2, "===> Hit already visited block at %+F\n", node));
@@ -338,7 +382,7 @@ static int WalkMem(ir_graph* irg, ir_node* node, ir_node* last_block)
 
        if (is_Phi(node)) {
                WalkMemPhi(irg, block, node);
-               return 0;
+               return block_change;
        } else if (is_Sync(node)) {
                UNIMPLEMENTED
        } else if (is_Return(node)) {
@@ -349,22 +393,41 @@ static int WalkMem(ir_graph* irg, ir_node* node, ir_node* last_block)
 
        if (WalkMem(irg, pred, block)) {
                // There was a block change
+               size_t block_arity = get_Block_n_cfgpreds(block);
+
                DB((dbg, LEVEL_3, "===> There is a block change before %+F\n", node));
-               if (get_Block_n_cfgpreds(block) == 1) {
+               if (block_arity == 1) {
                        // Just one predecessor, inherit its alias sets
-                       ir_nodeset_t* predsets = get_irn_link(get_nodes_block(pred));
+                       ir_node* pred_block = get_nodes_block(pred);
+                       ir_nodeset_t* predsets = get_irn_link(pred_block);
                        ir_nodeset_t* thissets = get_irn_link(block);
                        size_t i;
 
                        DB((dbg, LEVEL_3, "===> Copying the only predecessor's address sets\n"));
 
-                       for (i = 0; i < count_addrs; i++) {
-                               ir_nodeset_iterator_t prediter;
-                               ir_node* addr;
+                       if (ir_nodeset_size(&predsets[0]) == 0) {
+                               ir_node* unknown;
+
+                               DB((dbg, LEVEL_3, "===> The predecessor was not finished yet\n"));
+                               assert(Block_block_visited(pred_block));
+
+                               unknown = new_r_Unknown(irg, mode_M);
+                               for (i = 0; i < count_addrs; i++) {
+                                       ir_node* phi_unk = new_r_Phi(irg, block, 1, &unknown, mode_M);
+                                       DB((dbg, LEVEL_3, "===> Placing unfinished %+F for %+F in %+F\n", phi_unk, addrs[i], block));
+                                       set_irn_link(phi_unk, unfinished_phis[i]);
+                                       unfinished_phis[i] = phi_unk;
+                                       ir_nodeset_insert(&thissets[i], phi_unk);
+                               }
+                       } else {
+                               for (i = 0; i < count_addrs; i++) {
+                                       ir_nodeset_iterator_t prediter;
+                                       ir_node* addr;
 
-                               ir_nodeset_iterator_init(&prediter, &predsets[i]);
-                               while ((addr = ir_nodeset_iterator_next(&prediter)) != NULL) {
-                                       ir_nodeset_insert(&thissets[i], addr);
+                                       ir_nodeset_iterator_init(&prediter, &predsets[i]);
+                                       while ((addr = ir_nodeset_iterator_next(&prediter)) != NULL) {
+                                               ir_nodeset_insert(&thissets[i], addr);
+                                       }
                                }
                        }
                }
@@ -381,8 +444,7 @@ static int WalkMem(ir_graph* irg, ir_node* node, ir_node* last_block)
        } else {
                ir_nodeset_t sync_set;
                size_t i;
-               size_t sync_arity;
-               ir_nodeset_iterator_t sync_set_iter;
+               ir_node* after;
 
                DB((dbg, LEVEL_3, "===> Fallback: %+F aliases everything\n", node));
 
@@ -397,23 +459,8 @@ static int WalkMem(ir_graph* irg, ir_node* node, ir_node* last_block)
                        }
                }
 
-               assert(is_Return(node)); // XXX extend to other node types
-
-               sync_arity = ir_nodeset_size(&sync_set);
-               ir_nodeset_iterator_init(&sync_set_iter, &sync_set);
-               if (sync_arity == 1) {
-                       set_Return_mem(node, ir_nodeset_iterator_next(&sync_set_iter));
-               } else {
-                       ir_node** sync_in;
-                       ir_node* sync;
-
-                       NEW_ARR_A(ir_node*, sync_in, sync_arity);
-                       for (i = 0; i < sync_arity; i++) {
-                               sync_in[i] = ir_nodeset_iterator_next(&sync_set_iter);
-                       }
-                       sync = new_r_Sync(irg, block, sync_arity, sync_in);
-                       set_Return_mem(node, sync);
-               }
+               after = GenerateSync(irg, block, &sync_set);
+               set_irn_n(node, 0, after); // XXX unnice way to set the memory input
 
                for (i = 0; i < count_addrs; i++) {
                        ir_nodeset_iterator_t iter;
@@ -429,21 +476,73 @@ static int WalkMem(ir_graph* irg, ir_node* node, ir_node* last_block)
 }
 
 
+static void FinalisePhis(ir_graph* irg)
+{
+       size_t i;
+
+       for (i = 0; i < count_addrs; i++) {
+               ir_node* next_phi;
+               ir_node* phi;
+
+               for (phi = unfinished_phis[i]; phi != NULL; phi = next_phi) {
+                       ir_node* block = get_nodes_block(phi);
+                       size_t block_n_preds = get_Block_n_cfgpreds(block);
+
+                       next_phi = get_irn_link(phi);
+
+                       DB((dbg, LEVEL_4, "===> Finialising phi %+F in %+F\n", phi, block));
+
+                       if (block_n_preds == 1) {
+                               ir_node* pred_block = get_Block_cfgpred_block(block, 0);
+                               ir_nodeset_t* pred_sets = get_irn_link(pred_block);
+                               ir_node* after = GenerateSync(irg, pred_block, &pred_sets[i]);
+
+                               assert(is_Unknown(get_Phi_pred(phi, 0)));
+                               exchange(phi, after);
+                       } else {
+                               ir_node** in;
+                               size_t j;
+
+                               NEW_ARR_A(ir_node*, in, block_n_preds);
+                               for (j = 0; j < block_n_preds; j++) {
+                                       ir_node* pred_block = get_Block_cfgpred_block(block, j);
+                                       ir_nodeset_t* pred_sets = get_irn_link(pred_block);
+
+                                       if (is_Unknown(get_Phi_pred(phi, j))) {
+                                               set_Phi_pred(phi, j, GenerateSync(irg, pred_block, &pred_sets[i]));
+                                       }
+                               }
+                       }
+               }
+       }
+}
+
+
 static void Detotalise(ir_graph* irg)
 {
        ir_node* end_block = get_irg_end_block(irg);
        size_t npreds = get_Block_n_cfgpreds(end_block);
        size_t i;
 
+       unfinished_phis = XMALLOCN(ir_node, count_addrs);
+       for (i = 0; i < count_addrs; i++) {
+               unfinished_phis[i] = NULL;
+       }
+
        for (i = 0; i < npreds; i++) {
                ir_node* pred = get_Block_cfgpred(end_block, i);
                assert(is_Return(pred));
                DB((dbg, LEVEL_2, "===> Starting memory walk at %+F\n", pred));
                WalkMem(irg, pred, NULL);
        }
+
+       FinalisePhis(irg);
+       xfree(unfinished_phis);
 }
+#endif
 
 
+#if 0
 static void AddSyncPreds(ir_nodeset_t* preds, ir_node* sync)
 {
        size_t n = get_Sync_n_preds(sync);
@@ -459,7 +558,6 @@ static void AddSyncPreds(ir_nodeset_t* preds, ir_node* sync)
        }
 }
 
-
 static void NormaliseSync(ir_node* node, void* env)
 {
        ir_nodeset_t preds;
@@ -467,6 +565,7 @@ static void NormaliseSync(ir_node* node, void* env)
        ir_node** in;
        size_t count_preds;
        size_t i;
+       (void) env;
 
        if (!is_Sync(node)) return;
 
@@ -474,7 +573,7 @@ static void NormaliseSync(ir_node* node, void* env)
        AddSyncPreds(&preds, node);
 
        count_preds = ir_nodeset_size(&preds);
-       if (count_preds != get_Sync_n_preds(node)) {
+       if (count_preds != (unsigned)get_Sync_n_preds(node)) {
                NEW_ARR_A(ir_node*, in, count_preds);
                ir_nodeset_iterator_init(&iter, &preds);
                for (i = 0; i < count_preds; i++) {
@@ -488,13 +587,13 @@ static void NormaliseSync(ir_node* node, void* env)
        ir_nodeset_destroy(&preds);
 }
 
-
 void opt_ldst2(ir_graph* irg)
 {
        FIRM_DBG_REGISTER(dbg, "firm.opt.ldst2");
        DB((dbg, LEVEL_1, "===> Performing load/store optimisation on %+F\n", irg));
 
        normalize_one_return(irg);
+       dump_ir_block_graph(irg, "-prefluffig");
 
        obstack_init(&obst);
 
@@ -511,6 +610,7 @@ void opt_ldst2(ir_graph* irg)
        inc_irg_block_visited(irg);
        SetStartAddressesTop(irg);
        Detotalise(irg);
+       dump_ir_block_graph(irg, "-fluffig");
 
        irg_block_walk_graph(irg, AliasSetDestroyer, NULL, NULL);
        obstack_free(&obst, NULL);
@@ -519,4 +619,235 @@ void opt_ldst2(ir_graph* irg)
        irg_walk_graph(irg, NormaliseSync, NULL, NULL);
   optimize_graph_df(irg);
        irg_walk_graph(irg, NormaliseSync, NULL, NULL);
+       dump_ir_block_graph(irg, "-postfluffig");
+}
+#endif
+
+
+typedef struct parallelise_info
+{
+       ir_node      *origin_block;
+       ir_node      *origin_ptr;
+       ir_mode      *origin_mode;
+       ir_nodeset_t  this_mem;
+       ir_nodeset_t  user_mem;
+} parallelise_info;
+
+
+static void parallelise_load(parallelise_info *pi, ir_node *irn)
+{
+       /* There is no point in investigating the same subgraph twice */
+       if (ir_nodeset_contains(&pi->user_mem, irn))
+               return;
+
+       //ir_fprintf(stderr, "considering %+F\n", irn);
+       if (get_nodes_block(irn) == pi->origin_block) {
+               if (is_Proj(irn)) {
+                       ir_node *pred = get_Proj_pred(irn);
+                       if (is_Load(pred) &&
+                                       get_Load_volatility(pred) == volatility_non_volatile) {
+                               ir_node *mem = get_Load_mem(pred);
+                               //ir_nodeset_insert(&pi->this_mem, mem);
+                               ir_nodeset_insert(&pi->user_mem, irn);
+                               //ir_fprintf(stderr, "adding %+F to user set\n", irn);
+                               parallelise_load(pi, mem);
+                               return;
+                       } else if (is_Store(pred) &&
+                                       get_Store_volatility(pred) == volatility_non_volatile) {
+                               ir_mode *org_mode   = pi->origin_mode;
+                               ir_node *org_ptr    = pi->origin_ptr;
+                               ir_mode *store_mode = get_irn_mode(get_Store_value(pred));
+                               ir_node *store_ptr  = get_Store_ptr(pred);
+                               if (get_alias_relation(current_ir_graph, org_ptr, org_mode, store_ptr, store_mode) == ir_no_alias) {
+                                       ir_node *mem = get_Store_mem(pred);
+                                       //ir_fprintf(stderr, "Ld after St: %+F (%+F) does not alias %+F (%+F)\n", org_ptr, org_mode, store_ptr, store_mode);
+                                       ir_nodeset_insert(&pi->user_mem, irn);
+                                       //ir_fprintf(stderr, "adding %+F to user set\n", irn);
+                                       parallelise_load(pi, mem);
+                                       return;
+                               }
+                       }
+               } else if (is_Sync(irn)) {
+                       int n = get_Sync_n_preds(irn);
+                       int i;
+
+                       for (i = 0; i < n; ++i) {
+                               ir_node *sync_pred = get_Sync_pred(irn, i);
+                               parallelise_load(pi, sync_pred);
+                       }
+                       return;
+               }
+       }
+       ir_nodeset_insert(&pi->this_mem, irn);
+       //ir_fprintf(stderr, "adding %+F to this set\n", irn);
+}
+
+
+static void parallelise_store(parallelise_info *pi, ir_node *irn)
+{
+       /* There is no point in investigating the same subgraph twice */
+       if (ir_nodeset_contains(&pi->user_mem, irn))
+               return;
+
+       //ir_fprintf(stderr, "considering %+F\n", irn);
+       if (get_nodes_block(irn) == pi->origin_block) {
+               if (is_Proj(irn)) {
+                       ir_node *pred = get_Proj_pred(irn);
+                       if (is_Load(pred) &&
+                                       get_Load_volatility(pred) == volatility_non_volatile) {
+                               ir_mode *org_mode  = pi->origin_mode;
+                               ir_node *org_ptr   = pi->origin_ptr;
+                               ir_mode *load_mode = get_Load_mode(pred);
+                               ir_node *load_ptr  = get_Load_ptr(pred);
+                               if (get_alias_relation(current_ir_graph, org_ptr, org_mode, load_ptr, load_mode) == ir_no_alias) {
+                                       ir_node *mem = get_Load_mem(pred);
+                                       //ir_fprintf(stderr, "St after Ld: %+F (%+F) does not alias %+F (%+F)\n", org_ptr, org_mode, load_ptr, load_mode);
+                                       ir_nodeset_insert(&pi->user_mem, irn);
+                                       //ir_fprintf(stderr, "adding %+F to user set\n", irn);
+                                       parallelise_store(pi, mem);
+                                       return;
+                               }
+                       } else if (is_Store(pred) &&
+                                       get_Store_volatility(pred) == volatility_non_volatile) {
+                               ir_mode *org_mode   = pi->origin_mode;
+                               ir_node *org_ptr    = pi->origin_ptr;
+                               ir_mode *store_mode = get_irn_mode(get_Store_value(pred));
+                               ir_node *store_ptr  = get_Store_ptr(pred);
+                               if (get_alias_relation(current_ir_graph, org_ptr, org_mode, store_ptr, store_mode) == ir_no_alias) {
+                                       ir_node *mem;
+
+                                       //ir_fprintf(stderr, "St after St: %+F (%+F) does not alias %+F (%+F)\n", org_ptr, org_mode, store_ptr, store_mode);
+                                       ir_nodeset_insert(&pi->user_mem, irn);
+                                       //ir_fprintf(stderr, "adding %+F to user set\n", irn);
+                                       mem = get_Store_mem(pred);
+                                       parallelise_store(pi, mem);
+                                       return;
+                               }
+                       }
+               } else if (is_Sync(irn)) {
+                       int n = get_Sync_n_preds(irn);
+                       int i;
+
+                       for (i = 0; i < n; ++i) {
+                               ir_node *sync_pred = get_Sync_pred(irn, i);
+                               parallelise_store(pi, sync_pred);
+                       }
+                       return;
+               }
+       }
+       ir_nodeset_insert(&pi->this_mem, irn);
+       //ir_fprintf(stderr, "adding %+F to this set\n", irn);
+}
+
+
+static void walker(ir_node *proj, void *env)
+{
+       ir_node          *mem_op;
+       ir_node          *pred;
+       ir_node          *block;
+       int               n;
+       parallelise_info  pi;
+
+       (void)env;
+
+       if (!is_Proj(proj)) return;
+       if (get_irn_mode(proj) != mode_M) return;
+
+       mem_op = get_Proj_pred(proj);
+       if (is_Load(mem_op)) {
+               if (get_Load_volatility(mem_op) != volatility_non_volatile) return;
+
+               block = get_nodes_block(mem_op);
+               pred  = get_Load_mem(mem_op);
+               //ir_fprintf(stderr, "starting parallelise at %+F for %+F\n", pred, proj);
+
+               pi.origin_block = block,
+               pi.origin_ptr   = get_Load_ptr(mem_op);
+               pi.origin_mode  = get_Load_mode(mem_op);
+               ir_nodeset_init(&pi.this_mem);
+               ir_nodeset_init(&pi.user_mem);
+
+               parallelise_load(&pi, pred);
+       } else if (is_Store(mem_op)) {
+               if (get_Store_volatility(mem_op) != volatility_non_volatile) return;
+
+               block = get_nodes_block(mem_op);
+               pred  = get_Store_mem(mem_op);
+               //ir_fprintf(stderr, "starting parallelise at %+F for %+F\n", pred, proj);
+
+               pi.origin_block = block,
+               pi.origin_ptr   = get_Store_ptr(mem_op);
+               pi.origin_mode  = get_irn_mode(get_Store_value(mem_op));
+               ir_nodeset_init(&pi.this_mem);
+               ir_nodeset_init(&pi.user_mem);
+
+               parallelise_store(&pi, pred);
+       } else {
+               return;
+       }
+
+       n = ir_nodeset_size(&pi.user_mem);
+       if (n != 0) { /* nothing happened otherwise */
+               ir_graph               *irg  = current_ir_graph;
+               ir_node                *sync;
+               ir_node               **in;
+               ir_nodeset_iterator_t   iter;
+               int                     i;
+
+               ++n;
+               //ir_fprintf(stderr, "creating sync for users of %+F with %d inputs\n", proj, n);
+               NEW_ARR_A(ir_node*, in, n);
+               i = 0;
+               in[i++] = new_r_Unknown(irg, mode_M);
+               ir_nodeset_iterator_init(&iter, &pi.user_mem);
+               for (;;) {
+                       ir_node* p = ir_nodeset_iterator_next(&iter);
+                       if (p == NULL) break;
+                       in[i++] = p;
+               }
+               assert(i == n);
+               sync = new_r_Sync(block, n, in);
+               exchange(proj, sync);
+
+               assert(pn_Load_M == pn_Store_M);
+               proj = new_r_Proj(block, mem_op, mode_M, pn_Load_M);
+               set_Sync_pred(sync, 0, proj);
+
+               n = ir_nodeset_size(&pi.this_mem);
+               //ir_fprintf(stderr, "creating sync for %+F with %d inputs\n", mem_op, n);
+               ir_nodeset_iterator_init(&iter, &pi.this_mem);
+               if (n == 1) {
+                       sync = ir_nodeset_iterator_next(&iter);
+               } else {
+                       NEW_ARR_A(ir_node*, in, n);
+                       i = 0;
+                       for (;;) {
+                               ir_node* p = ir_nodeset_iterator_next(&iter);
+                               if (p == NULL) break;
+                               in[i++] = p;
+                       }
+                       assert(i == n);
+                       sync = new_r_Sync(block, n, in);
+               }
+               set_memop_mem(mem_op, sync);
+       }
+
+       ir_nodeset_destroy(&pi.this_mem);
+       ir_nodeset_destroy(&pi.user_mem);
+}
+
+
+void opt_sync(ir_graph *irg)
+{
+       //assure_irg_entity_usage_computed(irg);
+       //assure_irp_globals_entity_usage_computed();
+
+       irg_walk_graph(irg, NULL, walker, NULL);
+       //optimize_graph_df(irg);
+       //irg_walk_graph(irg, NormaliseSync, NULL, NULL);
+}
+
+ir_graph_pass_t *opt_sync_pass(const char *name, int verify, int dump)
+{
+       return def_graph_pass(name ? name : "opt_sync", verify, dump, opt_sync);
 }