Propagating live ranges backwards through calls to avoid coalescing variables in procedures with variables alive outside during the call.

src/dk/camelot64/kickc/icl/ControlFlowGraphBaseVisitor.java

@@ -44,11 +44,11 @@ public class ControlFlowGraphBaseVisitor<T> {
       }
    }
 
-   public T visitProcedureBegin(StatementProcedureBegin statement) {
+   public T visitProcedureBegin(StatementProcedureBegin procedureBegin) {
       return null;
    }
 
-   public T visitProcedureEnd(StatementProcedureEnd statement) {
+   public T visitProcedureEnd(StatementProcedureEnd procedureEnd) {
       return null;
    }
 
@@ -76,7 +76,7 @@ public class ControlFlowGraphBaseVisitor<T> {
       return null;
    }
 
-   public T visitCall(StatementCall callLValue) {
+   public T visitCall(StatementCall call) {
       return null;
    }
 

src/dk/camelot64/kickc/icl/ControlFlowGraphCopyVisitor.java

@@ -157,10 +157,10 @@ public class ControlFlowGraphCopyVisitor extends ControlFlowGraphBaseVisitor<Obj
    }
 
    @Override
-   public StatementCall visitCall(StatementCall callLValue) {
-      LValue lValue = callLValue.getlValue();
-      String procedureName = callLValue.getProcedureName();
-      List<RValue> parameters = callLValue.getParameters();
+   public StatementCall visitCall(StatementCall origCall) {
+      LValue lValue = origCall.getlValue();
+      String procedureName = origCall.getProcedureName();
+      List<RValue> parameters = origCall.getParameters();
       return new StatementCall(lValue, procedureName, parameters);
    }
 

src/dk/camelot64/kickc/icl/ProcedureRef.java

@@ -12,8 +12,21 @@ public class ProcedureRef extends SymbolRef {
       super(fullName);
    }
 
+   /**
+    * Get the label of the block where the procedure code starts
+    * @return The label of the code block
+    */
    @JsonIgnore
    public LabelRef getLabelRef() {
       return new LabelRef(getFullName());
    }
+
+   /**
+    * Get the label of the block containing the final procedure return
+    * @return The label of the code block
+    */
+   @JsonIgnore
+   public LabelRef getReturnBlock() {
+      return new LabelRef(getFullName()+"::@return");
+   }
 }

src/dk/camelot64/kickc/passes/Pass2AssertBlocks.java

@@ -71,11 +71,11 @@ public class Pass2AssertBlocks extends Pass2SsaAssertion {
       }
 
       @Override
-      public Void visitCall(StatementCall callLValue) {
-         ProcedureRef procedure = callLValue.getProcedure();
+      public Void visitCall(StatementCall call) {
+         ProcedureRef procedure = call.getProcedure();
          LabelRef procLabelRef = procedure.getLabelRef();
          assertBlock(procLabelRef);
-         return super.visitCall(callLValue);
+         return super.visitCall(call);
       }
 
       @Override

src/dk/camelot64/kickc/passes/Pass2AssertNoCallLvalues.java

@@ -20,9 +20,9 @@ public class Pass2AssertNoCallLvalues extends Pass2SsaAssertion {
       ControlFlowGraphBaseVisitor<Void> checkCalls = new ControlFlowGraphBaseVisitor<Void>() {
 
          @Override
-         public Void visitCall(StatementCall callLValue) {
-            if(callLValue.getlValue()!=null) {
-               throw new AssertionFailed("No call lValue allowed! "+callLValue);
+         public Void visitCall(StatementCall call) {
+            if(call.getlValue()!=null) {
+               throw new AssertionFailed("No call lValue allowed! "+ call);
             }
             return null;
          }

src/dk/camelot64/kickc/passes/Pass2AssertNoCallParameters.java

@@ -18,10 +18,10 @@ public class Pass2AssertNoCallParameters extends Pass2SsaAssertion {
       ControlFlowGraphBaseVisitor<Void> checkCalls = new ControlFlowGraphBaseVisitor<Void>() {
 
          @Override
-         public Void visitCall(StatementCall callLValue) {
-            List<RValue> parameters = callLValue.getParameters();
+         public Void visitCall(StatementCall call) {
+            List<RValue> parameters = call.getParameters();
             if(parameters!=null && parameters.size()>0) {
-               throw new AssertionFailed("No call parameters allowed! "+callLValue);
+               throw new AssertionFailed("No call parameters allowed! "+ call);
             }
             return null;
          }

src/dk/camelot64/kickc/passes/Pass2AssertNoProcs.java

@@ -15,13 +15,13 @@ public class Pass2AssertNoProcs extends Pass2SsaAssertion {
       ControlFlowGraphBaseVisitor<Void> checkCalls = new ControlFlowGraphBaseVisitor<Void>() {
 
          @Override
-         public Void visitProcedureBegin(StatementProcedureBegin statement) {
-            throw new AssertionFailed("No proc statements allowed! "+statement);
+         public Void visitProcedureBegin(StatementProcedureBegin procedureBegin) {
+            throw new AssertionFailed("No proc statements allowed! "+ procedureBegin);
          }
 
          @Override
-         public Void visitProcedureEnd(StatementProcedureEnd statement) {
-            throw new AssertionFailed("No proc statements allowed! "+statement);
+         public Void visitProcedureEnd(StatementProcedureEnd procedureEnd) {
+            throw new AssertionFailed("No proc statements allowed! "+ procedureEnd);
          }
       };
       checkCalls.visitGraph(getGraph());

src/dk/camelot64/kickc/passes/Pass2AssertSymbols.java

@@ -91,19 +91,19 @@ public class Pass2AssertSymbols extends Pass2SsaAssertion {
       }
 
       @Override
-      public Void visitProcedureBegin(StatementProcedureBegin statement) {
-         ProcedureRef procedureRef = statement.getProcedure();
+      public Void visitProcedureBegin(StatementProcedureBegin procedureBegin) {
+         ProcedureRef procedureRef = procedureBegin.getProcedure();
          Procedure procedure = programScope.getProcedure(procedureRef);
          symbols.add(procedure);
-         return super.visitProcedureBegin(statement);
+         return super.visitProcedureBegin(procedureBegin);
       }
 
       @Override
-      public Void visitProcedureEnd(StatementProcedureEnd statement) {
-         ProcedureRef procedureRef = statement.getProcedure();
+      public Void visitProcedureEnd(StatementProcedureEnd procedureEnd) {
+         ProcedureRef procedureRef = procedureEnd.getProcedure();
          Procedure procedure = programScope.getProcedure(procedureRef);
          symbols.add(procedure);
-         return super.visitProcedureEnd(statement);
+         return super.visitProcedureEnd(procedureEnd);
       }
 
       @Override
@@ -141,15 +141,15 @@ public class Pass2AssertSymbols extends Pass2SsaAssertion {
       }
 
       @Override
-      public Void visitCall(StatementCall callLValue) {
-         addSymbol(callLValue.getlValue());
-         addSymbol(callLValue.getProcedure());
-         if(callLValue.getParameters()!=null) {
-            for (RValue param : callLValue.getParameters()) {
+      public Void visitCall(StatementCall call) {
+         addSymbol(call.getlValue());
+         addSymbol(call.getProcedure());
+         if(call.getParameters()!=null) {
+            for (RValue param : call.getParameters()) {
                addSymbol(param);
             }
          }
-         return super.visitCall(callLValue);
+         return super.visitCall(call);
       }
 
       @Override

src/dk/camelot64/kickc/passes/Pass3LiveRangesAnalysis.java

@@ -147,15 +147,15 @@ public class Pass3LiveRangesAnalysis {
       }
 
       @Override
-      public Void visitCall(StatementCall callLValue) {
-         if (callLValue.getlValue() instanceof PointerDereferenceIndexed) {
-            addInitialLiveRange(((PointerDereferenceIndexed) callLValue.getlValue()).getPointer());
-            addInitialLiveRange(((PointerDereferenceIndexed) callLValue.getlValue()).getIndex());
-         } else if (callLValue.getlValue() instanceof PointerDereferenceSimple) {
-            addInitialLiveRange(((PointerDereferenceSimple) callLValue.getlValue()).getPointer());
+      public Void visitCall(StatementCall call) {
+         if (call.getlValue() instanceof PointerDereferenceIndexed) {
+            addInitialLiveRange(((PointerDereferenceIndexed) call.getlValue()).getPointer());
+            addInitialLiveRange(((PointerDereferenceIndexed) call.getlValue()).getIndex());
+         } else if (call.getlValue() instanceof PointerDereferenceSimple) {
+            addInitialLiveRange(((PointerDereferenceSimple) call.getlValue()).getPointer());
          }
-         if (callLValue.getParameters() != null) {
-            for (RValue parameter : callLValue.getParameters()) {
+         if (call.getParameters() != null) {
+            for (RValue parameter : call.getParameters()) {
                addInitialLiveRange(parameter);
             }
          }
@@ -287,19 +287,41 @@ public class Pass3LiveRangesAnalysis {
          }
       }
 
+      /**
+       * Get the statement executed just before entering a specific block
+       *
+       * @param block The block to find the previous statement for
+       * @return The statement executed just before entering the block.
+       * If there are several predecessor blocks multiple statements are returned.
+       */
       private ArrayList<Statement> getPreviousStatements(ControlFlowBlock block) {
          ArrayList<Statement> statements = new ArrayList<>();
          List<ControlFlowBlock> predecessors = program.getGraph().getPredecessors(block);
          for (ControlFlowBlock predecessor : predecessors) {
-            List<Statement> predecessorStatements = predecessor.getStatements();
-            if (predecessorStatements.size() == 0) {
-               // Predecessor has no statements - go further back!
-               statements.addAll(getPreviousStatements(predecessor));
-            } else {
-               // Add last statement from predecessor
-               Statement predecessorLastStatement = predecessorStatements.get(predecessorStatements.size() - 1);
-               statements.add(predecessorLastStatement);
-            }
+            ArrayList<Statement> lastStatements = getLastStatements(predecessor);
+
+
+            statements.addAll(lastStatements);
+         }
+         return statements;
+      }
+
+      /**
+       * Get the last statement executed in a specific block.
+       * If the block is empty the last statement of the previous block is returned.
+       * @param block The block to examine
+       * @return The last statement of the block (or the last statement of previous blocks if the block is empty)
+       */
+      private ArrayList<Statement> getLastStatements(ControlFlowBlock block) {
+         ArrayList<Statement> statements = new ArrayList<>();
+         List<Statement> blockStatements = block.getStatements();
+         if (blockStatements.size() == 0) {
+            // Block has no statements - go further back!
+            statements.addAll(getPreviousStatements(block));
+         } else {
+            // Add last statement from block
+            Statement predecessorLastStatement = blockStatements.get(blockStatements.size() - 1);
+            statements.add(predecessorLastStatement);
          }
          return statements;
       }
@@ -315,47 +337,48 @@ public class Pass3LiveRangesAnalysis {
       }
 
       @Override
-      public Void visitCall(StatementCall callLValue) {
-         if (callLValue.getlValue() != null) {
-            propagate(callLValue, getPreviousStatements(), Arrays.asList(callLValue.getlValue()));
-         }
+      public Void visitCall(StatementCall call) {
+         propagate(call, getPreviousStatements(), null);
+         // Also propagate back through all statements of the procedure
+         ProcedureRef procedure = call.getProcedure();
+         LabelRef procedureReturnBlock = procedure.getReturnBlock();
+         ControlFlowBlock returnBlock = program.getGraph().getBlock(procedureReturnBlock);
+         propagate(call, getLastStatements(returnBlock), null);
          return null;
       }
 
       @Override
       public Void visitAssignment(StatementAssignment assignment) {
-         if (assignment.getlValue() != null) {
-            propagate(assignment, getPreviousStatements(), Arrays.asList(assignment.getlValue()));
-         }
+         propagate(assignment, getPreviousStatements(), Arrays.asList(assignment.getlValue()));
          return null;
       }
 
       @Override
       public Void visitConditionalJump(StatementConditionalJump conditionalJump) {
-         propagate(conditionalJump, getPreviousStatements(), new ArrayList<LValue>());
+         propagate(conditionalJump, getPreviousStatements(), null);
          return null;
       }
 
       @Override
       public Void visitJump(StatementJump jump) {
-         propagate(jump, getPreviousStatements(), new ArrayList<LValue>());
+         propagate(jump, getPreviousStatements(), null);
          return null;
       }
 
       @Override
       public Void visitReturn(StatementReturn aReturn) {
-         propagate(aReturn, getPreviousStatements(), new ArrayList<LValue>());
+         propagate(aReturn, getPreviousStatements(), null);
          return null;
       }
 
       @Override
-      public Void visitProcedureBegin(StatementProcedureBegin statement) {
-         throw new RuntimeException("Statement not supported during live range propagation. Should be eliminated in earlier phase. " + statement);
+      public Void visitProcedureBegin(StatementProcedureBegin procedureBegin) {
+         throw new RuntimeException("Statement not supported during live range propagation. Should be eliminated in earlier phase. " + procedureBegin);
       }
 
       @Override
-      public Void visitProcedureEnd(StatementProcedureEnd statement) {
-         throw new RuntimeException("Statement not supported during live range propagation. Should be eliminated in earlier phase. " + statement);
+      public Void visitProcedureEnd(StatementProcedureEnd procedureEnd) {
+         throw new RuntimeException("Statement not supported during live range propagation. Should be eliminated in earlier phase. " + procedureEnd);
       }
 
       @Override

src/dk/camelot64/kickc/test/TestCompilationOutput.java

@@ -58,6 +58,11 @@ public class TestCompilationOutput extends TestCase {
       tester.testFile("loopnest");
    }
 
+   public void testLoopNest2() throws IOException, URISyntaxException {
+      TestCompilationOutput tester = new TestCompilationOutput();
+      tester.testFile("loopnest2");
+   }
+
 
    private void testFile(String fileName) throws IOException, URISyntaxException {
       String inputPath = testPath + fileName + ".kc";

src/dk/camelot64/kickc/test/loopnest.kc

@@ -3,31 +3,15 @@ byte* SCREEN = $0400;
 main();
 
 void main() {
-    byte i=100;
-    do {
-        byte j=100;
-        do {
-            nest1();
-        } while (--j>0)
-    } while (--i>0)
+  byte i=100;
+  do {
+    nest();
+  } while (--i>0)
 }
 
-void nest1() {
-    byte i=100;
-    do {
-        byte j=100;
-        do {
-            nest2();
-        } while (--j>0)
-    } while (--i>0)
-}
-
-void nest2() {
-    byte i=100;
-    do {
-        byte j=100;
-        do {
-            *SCREEN = j;
-        } while (--j>0)
-    } while (--i>0)
+void nest() {
+  byte j=100;
+  do {
+    *SCREEN = j;
+  } while (--j>0)
 }

src/dk/camelot64/kickc/test/loopnest2.kc

@@ -0,0 +1,33 @@
+byte* SCREEN = $0400;
+
+main();
+
+void main() {
+    byte i=100;
+    do {
+        byte j=100;
+        do {
+            nest1();
+        } while (--j>0)
+    } while (--i>0)
+}
+
+void nest1() {
+    byte i=100;
+    do {
+        byte j=100;
+        do {
+            nest2();
+        } while (--j>0)
+    } while (--i>0)
+}
+
+void nest2() {
+    byte i=100;
+    do {
+        byte j=100;
+        do {
+            *SCREEN = j;
+        } while (--j>0)
+    } while (--i>0)
+}

src/dk/camelot64/kickc/test/ref/loopnest.asm

@@ -7,63 +7,23 @@ main__B1_from_main:
   sta 2
 main__B1_from_B3:
 main__B1:
-main__B2_from_B1:
-  lda #100
-  sta 3
-main__B2_from_B5:
-main__B2:
-  jsr nest1
-main__B5:
-  dec 3
-  lda 3
-  bne main__B2_from_B5
+  jsr nest
 main__B3:
   dec 2
   lda 2
   bne main__B1_from_B3
 main__Breturn:
   rts
-nest1:
-nest1__B1_from_nest1:
-  lda #100
-  sta 2
-nest1__B1_from_B3:
-nest1__B1:
-nest1__B2_from_B1:
+nest:
+nest__B1_from_nest:
   lda #100
   sta 3
-nest1__B2_from_B5:
-nest1__B2:
-  jsr nest2
-nest1__B5:
-  dec 3
-  lda 3
-  bne nest1__B2_from_B5
-nest1__B3:
-  dec 2
-  lda 2
-  bne nest1__B1_from_B3
-nest1__Breturn:
-  rts
-nest2:
-nest2__B1_from_nest2:
-  lda #100
-  sta 2
-nest2__B1_from_B3:
-nest2__B1:
-nest2__B2_from_B1:
-  lda #100
-  sta 3
-nest2__B2_from_B2:
-nest2__B2:
+nest__B1_from_B1:
+nest__B1:
   lda 3
   sta 1024
   dec 3
   lda 3
-  bne nest2__B2_from_B2
-nest2__B3:
-  dec 2
-  lda 2
-  bne nest2__B1_from_B3
-nest2__Breturn:
+  bne nest__B1_from_B1
+nest__Breturn:
   rts

src/dk/camelot64/kickc/test/ref/loopnest.cfg

@@ -5,58 +5,24 @@
 main: from @BEGIN
   to:main::@1
 main::@1: from main main::@3
-  [1] (byte) main::i#2 ← phi( main/(byte) 100 main::@3/(byte) main::i#1 ) [ ]
-  to:main::@2
-main::@2: from main::@1 main::@5
-  [2] (byte) main::j#2 ← phi( main::@1/(byte) 100 main::@5/(byte) main::j#1 ) [ ]
-  [3] call nest1 param-assignment [ main::j#2 main::i#2 ]
-  to:main::@5
-main::@5: from main::@2
-  [4] (byte) main::j#1 ← -- (byte) main::j#2 [ main::j#1 main::i#2 ]
-  [5] if((byte) main::j#1>(byte) 0) goto main::@2 [ main::j#1 main::i#2 ]
+  [1] (byte) main::i#2 ← phi( main/(byte) 100 main::@3/(byte) main::i#1 ) [ main::i#2 ]
+  [2] call nest param-assignment [ main::i#2 ]
   to:main::@3
-main::@3: from main::@5
-  [6] (byte) main::i#1 ← -- (byte) main::i#2 [ main::i#1 ]
-  [7] if((byte) main::i#1>(byte) 0) goto main::@1 [ main::i#1 ]
+main::@3: from main::@1
+  [3] (byte) main::i#1 ← -- (byte) main::i#2 [ main::i#1 ]
+  [4] if((byte) main::i#1>(byte) 0) goto main::@1 [ main::i#1 ]
   to:main::@return
 main::@return: from main::@3
-  [8] return  [ ]
+  [5] return  [ ]
   to:@RETURN
-nest1: from main::@2
-  to:nest1::@1
-nest1::@1: from nest1 nest1::@3
-  [9] (byte) nest1::i#2 ← phi( nest1/(byte) 100 nest1::@3/(byte) nest1::i#1 ) [ ]
-  to:nest1::@2
-nest1::@2: from nest1::@1 nest1::@5
-  [10] (byte) nest1::j#2 ← phi( nest1::@1/(byte) 100 nest1::@5/(byte) nest1::j#1 ) [ ]
-  [11] call nest2 param-assignment [ nest1::j#2 nest1::i#2 ]
-  to:nest1::@5
-nest1::@5: from nest1::@2
-  [12] (byte) nest1::j#1 ← -- (byte) nest1::j#2 [ nest1::j#1 nest1::i#2 ]
-  [13] if((byte) nest1::j#1>(byte) 0) goto nest1::@2 [ nest1::j#1 nest1::i#2 ]
-  to:nest1::@3
-nest1::@3: from nest1::@5
-  [14] (byte) nest1::i#1 ← -- (byte) nest1::i#2 [ nest1::i#1 ]
-  [15] if((byte) nest1::i#1>(byte) 0) goto nest1::@1 [ nest1::i#1 ]
-  to:nest1::@return
-nest1::@return: from nest1::@3
-  [16] return  [ ]
-  to:@RETURN
-nest2: from nest1::@2
-  to:nest2::@1
-nest2::@1: from nest2 nest2::@3
-  [17] (byte) nest2::i#2 ← phi( nest2/(byte) 100 nest2::@3/(byte) nest2::i#1 ) [ nest2::i#2 ]
-  to:nest2::@2
-nest2::@2: from nest2::@1 nest2::@2
-  [18] (byte) nest2::j#2 ← phi( nest2::@1/(byte) 100 nest2::@2/(byte) nest2::j#1 ) [ nest2::j#2 nest2::i#2 ]
-  [19] *((word) 1024) ← (byte) nest2::j#2 [ nest2::j#2 nest2::i#2 ]
-  [20] (byte) nest2::j#1 ← -- (byte) nest2::j#2 [ nest2::j#1 nest2::i#2 ]
-  [21] if((byte) nest2::j#1>(byte) 0) goto nest2::@2 [ nest2::j#1 nest2::i#2 ]
-  to:nest2::@3
-nest2::@3: from nest2::@2
-  [22] (byte) nest2::i#1 ← -- (byte) nest2::i#2 [ nest2::i#1 ]
-  [23] if((byte) nest2::i#1>(byte) 0) goto nest2::@1 [ nest2::i#1 ]
-  to:nest2::@return
-nest2::@return: from nest2::@3
-  [24] return  [ ]
+nest: from main::@1
+  to:nest::@1
+nest::@1: from nest nest::@1
+  [6] (byte) nest::j#2 ← phi( nest/(byte) 100 nest::@1/(byte) nest::j#1 ) [ main::i#2 nest::j#2 ]
+  [7] *((word) 1024) ← (byte) nest::j#2 [ main::i#2 nest::j#2 ]
+  [8] (byte) nest::j#1 ← -- (byte) nest::j#2 [ main::i#2 nest::j#1 ]
+  [9] if((byte) nest::j#1>(byte) 0) goto nest::@1 [ main::i#2 nest::j#1 ]
+  to:nest::@return
+nest::@return: from nest::@1
+  [10] return  [ main::i#2 ]
   to:@RETURN

src/dk/camelot64/kickc/test/ref/loopnest.sym

@@ -3,42 +3,19 @@
 (byte*) SCREEN
 (void()) main()
 (label) main::@1
-(label) main::@2
 (label) main::@3
-(label) main::@5
 (label) main::@return
 (byte) main::i
 (byte) main::i#1 zp byte:2
 (byte) main::i#2 zp byte:2
-(byte) main::j
-(byte) main::j#1 zp byte:3
-(byte) main::j#2 zp byte:3
 
-(void()) nest1()
-(label) nest1::@1
-(label) nest1::@2
-(label) nest1::@3
-(label) nest1::@5
-(label) nest1::@return
-(byte) nest1::i
-(byte) nest1::i#1 zp byte:2
-(byte) nest1::i#2 zp byte:2
-(byte) nest1::j
-(byte) nest1::j#1 zp byte:3
-(byte) nest1::j#2 zp byte:3
-
-(void()) nest2()
-(label) nest2::@1
-(label) nest2::@2
-(label) nest2::@3
-(label) nest2::@return
-(byte) nest2::i
-(byte) nest2::i#1 zp byte:2
-(byte) nest2::i#2 zp byte:2
-(byte) nest2::j
-(byte) nest2::j#1 zp byte:3
-(byte) nest2::j#2 zp byte:3
+(void()) nest()
+(label) nest::@1
+(label) nest::@return
+(byte) nest::j
+(byte) nest::j#1 zp byte:3
+(byte) nest::j#2 zp byte:3
 
 
-zp byte:2 [ main::i#2 main::i#1 nest1::i#2 nest1::i#1 nest2::i#2 nest2::i#1 ]
-zp byte:3 [ main::j#2 main::j#1 nest1::j#2 nest1::j#1 nest2::j#2 nest2::j#1 ]
+zp byte:2 [ main::i#2 main::i#1 ]
+zp byte:3 [ nest::j#2 nest::j#1 ]

src/dk/camelot64/kickc/test/ref/loopnest2.asm

@@ -0,0 +1,69 @@
+BBEGIN:
+  jsr main
+BEND:
+main:
+main__B1_from_main:
+  lda #100
+  sta 2
+main__B1_from_B3:
+main__B1:
+main__B2_from_B1:
+  lda #100
+  sta 3
+main__B2_from_B5:
+main__B2:
+  jsr nest1
+main__B5:
+  dec 3
+  lda 3
+  bne main__B2_from_B5
+main__B3:
+  dec 2
+  lda 2
+  bne main__B1_from_B3
+main__Breturn:
+  rts
+nest1:
+nest1__B1_from_nest1:
+  lda #100
+  sta 4
+nest1__B1_from_B3:
+nest1__B1:
+nest1__B2_from_B1:
+  lda #100
+  sta 5
+nest1__B2_from_B5:
+nest1__B2:
+  jsr nest2
+nest1__B5:
+  dec 5
+  lda 5
+  bne nest1__B2_from_B5
+nest1__B3:
+  dec 4
+  lda 4
+  bne nest1__B1_from_B3
+nest1__Breturn:
+  rts
+nest2:
+nest2__B1_from_nest2:
+  lda #100
+  sta 6
+nest2__B1_from_B3:
+nest2__B1:
+nest2__B2_from_B1:
+  lda #100
+  sta 7
+nest2__B2_from_B2:
+nest2__B2:
+  lda 7
+  sta 1024
+  dec 7
+  lda 7
+  bne nest2__B2_from_B2
+nest2__B3:
+  dec 6
+  lda 6
+  bne nest2__B1_from_B3
+nest2__Breturn:
+  rts

src/dk/camelot64/kickc/test/ref/loopnest2.cfg

@@ -0,0 +1,62 @@
+@BEGIN: from
+  [0] call main param-assignment [ ]
+  to:@END
+@END: from @BEGIN
+main: from @BEGIN
+  to:main::@1
+main::@1: from main main::@3
+  [1] (byte) main::i#2 ← phi( main/(byte) 100 main::@3/(byte) main::i#1 ) [ main::i#2 ]
+  to:main::@2
+main::@2: from main::@1 main::@5
+  [2] (byte) main::j#2 ← phi( main::@1/(byte) 100 main::@5/(byte) main::j#1 ) [ main::j#2 main::i#2 ]
+  [3] call nest1 param-assignment [ main::j#2 main::i#2 ]
+  to:main::@5
+main::@5: from main::@2
+  [4] (byte) main::j#1 ← -- (byte) main::j#2 [ main::j#1 main::i#2 ]
+  [5] if((byte) main::j#1>(byte) 0) goto main::@2 [ main::j#1 main::i#2 ]
+  to:main::@3
+main::@3: from main::@5
+  [6] (byte) main::i#1 ← -- (byte) main::i#2 [ main::i#1 ]
+  [7] if((byte) main::i#1>(byte) 0) goto main::@1 [ main::i#1 ]
+  to:main::@return
+main::@return: from main::@3
+  [8] return  [ ]
+  to:@RETURN
+nest1: from main::@2
+  to:nest1::@1
+nest1::@1: from nest1 nest1::@3
+  [9] (byte) nest1::i#2 ← phi( nest1/(byte) 100 nest1::@3/(byte) nest1::i#1 ) [ main::j#2 main::i#2 nest1::i#2 ]
+  to:nest1::@2
+nest1::@2: from nest1::@1 nest1::@5
+  [10] (byte) nest1::j#2 ← phi( nest1::@1/(byte) 100 nest1::@5/(byte) nest1::j#1 ) [ main::j#2 main::i#2 nest1::j#2 nest1::i#2 ]
+  [11] call nest2 param-assignment [ main::j#2 main::i#2 nest1::j#2 nest1::i#2 ]
+  to:nest1::@5
+nest1::@5: from nest1::@2
+  [12] (byte) nest1::j#1 ← -- (byte) nest1::j#2 [ main::j#2 main::i#2 nest1::j#1 nest1::i#2 ]
+  [13] if((byte) nest1::j#1>(byte) 0) goto nest1::@2 [ main::j#2 main::i#2 nest1::j#1 nest1::i#2 ]
+  to:nest1::@3
+nest1::@3: from nest1::@5
+  [14] (byte) nest1::i#1 ← -- (byte) nest1::i#2 [ main::j#2 main::i#2 nest1::i#1 ]
+  [15] if((byte) nest1::i#1>(byte) 0) goto nest1::@1 [ main::j#2 main::i#2 nest1::i#1 ]
+  to:nest1::@return
+nest1::@return: from nest1::@3
+  [16] return  [ main::j#2 main::i#2 ]
+  to:@RETURN
+nest2: from nest1::@2
+  to:nest2::@1
+nest2::@1: from nest2 nest2::@3
+  [17] (byte) nest2::i#2 ← phi( nest2/(byte) 100 nest2::@3/(byte) nest2::i#1 ) [ main::j#2 main::i#2 nest1::j#2 nest1::i#2 nest2::i#2 ]
+  to:nest2::@2
+nest2::@2: from nest2::@1 nest2::@2
+  [18] (byte) nest2::j#2 ← phi( nest2::@1/(byte) 100 nest2::@2/(byte) nest2::j#1 ) [ main::j#2 main::i#2 nest1::j#2 nest1::i#2 nest2::j#2 nest2::i#2 ]
+  [19] *((word) 1024) ← (byte) nest2::j#2 [ main::j#2 main::i#2 nest1::j#2 nest1::i#2 nest2::j#2 nest2::i#2 ]
+  [20] (byte) nest2::j#1 ← -- (byte) nest2::j#2 [ main::j#2 main::i#2 nest1::j#2 nest1::i#2 nest2::j#1 nest2::i#2 ]
+  [21] if((byte) nest2::j#1>(byte) 0) goto nest2::@2 [ main::j#2 main::i#2 nest1::j#2 nest1::i#2 nest2::j#1 nest2::i#2 ]
+  to:nest2::@3
+nest2::@3: from nest2::@2
+  [22] (byte) nest2::i#1 ← -- (byte) nest2::i#2 [ main::j#2 main::i#2 nest1::j#2 nest1::i#2 nest2::i#1 ]
+  [23] if((byte) nest2::i#1>(byte) 0) goto nest2::@1 [ main::j#2 main::i#2 nest1::j#2 nest1::i#2 nest2::i#1 ]
+  to:nest2::@return
+nest2::@return: from nest2::@3
+  [24] return  [ main::j#2 main::i#2 nest1::j#2 nest1::i#2 ]
+  to:@RETURN

src/dk/camelot64/kickc/test/ref/loopnest2.sym

@@ -0,0 +1,48 @@
+(label) @BEGIN
+(label) @END
+(byte*) SCREEN
+(void()) main()
+(label) main::@1
+(label) main::@2
+(label) main::@3
+(label) main::@5
+(label) main::@return
+(byte) main::i
+(byte) main::i#1 zp byte:2
+(byte) main::i#2 zp byte:2
+(byte) main::j
+(byte) main::j#1 zp byte:3
+(byte) main::j#2 zp byte:3
+
+(void()) nest1()
+(label) nest1::@1
+(label) nest1::@2
+(label) nest1::@3
+(label) nest1::@5
+(label) nest1::@return
+(byte) nest1::i
+(byte) nest1::i#1 zp byte:4
+(byte) nest1::i#2 zp byte:4
+(byte) nest1::j
+(byte) nest1::j#1 zp byte:5
+(byte) nest1::j#2 zp byte:5
+
+(void()) nest2()
+(label) nest2::@1
+(label) nest2::@2
+(label) nest2::@3
+(label) nest2::@return
+(byte) nest2::i
+(byte) nest2::i#1 zp byte:6
+(byte) nest2::i#2 zp byte:6
+(byte) nest2::j
+(byte) nest2::j#1 zp byte:7
+(byte) nest2::j#2 zp byte:7
+
+
+zp byte:2 [ main::i#2 main::i#1 ]
+zp byte:3 [ main::j#2 main::j#1 ]
+zp byte:4 [ nest1::i#2 nest1::i#1 ]
+zp byte:5 [ nest1::j#2 nest1::j#1 ]
+zp byte:6 [ nest2::i#2 nest2::i#1 ]
+zp byte:7 [ nest2::j#2 nest2::j#1 ]