MemStore interface (#201)

* Hook for pre-encoding work needed by M2

* Add MemStore interface

* Add both MemLoad and MemStore interfaces

* Fix NPE printing StopNode

* Attach merged mem to return when forcing a loop exit

* Made requested changes. This breaks a few tests, possibly because...

...I am not sure whether some X86 ops are loads or stores.

* Mach ops need anti-deps too

MemOp subclasses are either "Load-like" or "Store-like" based on a flag, and not on subclassing LoadNode nor StoreNode.
Mach ops pick up anti-deps, no reg mask for those.
x86 bug: do not allow "dst = [mem] + #imm", no such instruction
Empty merge-mem folds away.
x86 add-to-mem works both ways

---------

Co-authored-by: Cliff Click <cliffc@acm.org>

2 files changed, 9 insertions, 9 deletions

diff --git a/chapter21/src/test/java/com/seaofnodes/simple/BrainFuckTest.java b/chapter21/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
index ba852c9e..991a2f66 100644
--- a/chapter21/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
+++ b/chapter21/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
@@ -63,7 +63,7 @@ for( int pc = 0; pc < program#; pc++ ) {
 return output;
 """;
         Chapter21Test.testCPU(src,"x86_64_v2", "SystemV",40,null);
-        Chapter21Test.testCPU(src,"riscv"    , "SystemV",30,null);
+        Chapter21Test.testCPU(src,"riscv"    , "SystemV",44,null);
         Chapter21Test.testCPU(src,"arm"      , "SystemV",26,null);
         //assertEquals("Hello World!\n", Eval2.eval(code, 0, 10000));
     }
diff --git a/chapter21/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java b/chapter21/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
index 4bfa7628..7ba9272f 100644
--- a/chapter21/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
+++ b/chapter21/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
@@ -248,20 +248,20 @@ public class Scheduler {
             assert data.block != null;
             assert data.users == 0;
 
-            if (data.node instanceof LoadNode l) {
+            if (data.node instanceof MemOpNode l && l._isLoad) {
                 assert isValid(data);
                 // Handle anti-deps of load nodes.
                 // At this point all anti-dep nodes are scheduled,
                 // but they did not refine the placement
                 // so do that now.
-                var mem = l.in(1);
+                var mem = data.node.in(1);
                 for(var out : mem._outputs) {
                     if (out instanceof PhiNode p) {
                         var r = p.in(0);
                         for (int i = 1; i < p.nIns(); i++) {
                             if (p.in(i) == mem) optionalRefinePlacement(data, r.in(i));
                         }
-                    } else if (!(out instanceof LoadNode)) {
+                    } else if (!(out instanceof MemOpNode ld && ld._isLoad)) {
                         optionalRefinePlacement(data, out);
                     }
                 }
@@ -273,11 +273,11 @@ public class Scheduler {
             for(var in:data.node._inputs) {
                 if (in!=null) update(d(in), data.block);
             }
-            if (data.node instanceof StoreNode s) {
+            if (data.node instanceof MemOpNode s && !s._isLoad) {
                 // Store nodes have anti-deps to load nodes.
                 // So decrease the uses of these loads when the store is placed.
-                for (var out: s.in(1)._outputs) {
-                    if (out instanceof LoadNode) od(out).ifPresent(this::decUsers);
+                for (var out: ((Node)s).in(1)._outputs) {
+                    if (out instanceof MemOpNode ld && ld._isLoad) od(out).ifPresent(this::decUsers);
                 }
             }
         }
@@ -471,14 +471,14 @@ public class Scheduler {
             } else {
                 for (var in : node._inputs) if (in != null && !(in instanceof CFGNode)) markAlive(dataQueue, in, false);
             }
-            if (node instanceof StoreNode) mem.push(data);
+            if (node instanceof MemOpNode s && !s._isLoad) mem.push(data);
         }
         // Handle store nodes and increase load with an anti-dep to the store.
         while (!mem.isEmpty()) {
             var data = mem.pop();
             node = data.node;
             for(var out:node.in(1)._outputs) {
-                if (out instanceof LoadNode) od(out).ifPresent(d->d.users++);
+                if (out instanceof MemOpNode ld && ld._isLoad) od(out).ifPresent(d->d.users++);
             }
         }
     }