From 7d08159fb2082a5a83839189f0a9192f78aaa325 Mon Sep 17 00:00:00 2001
From: jespergravgaard <jesper@balmangravgaard.dk>
Date: Mon, 27 Nov 2017 01:12:29 +0100
Subject: [PATCH] Added test for lda #>0 / lda #<0.

---
 .../dk/camelot64/kickc/test/ref/immzero.asm   |  24 +
 .../dk/camelot64/kickc/test/ref/immzero.cfg   |  19 +
 .../dk/camelot64/kickc/test/ref/immzero.log   | 857 ++++++++++++++++++
 .../dk/camelot64/kickc/test/ref/immzero.sym   |  16 +
 4 files changed, 916 insertions(+)
 create mode 100644 src/main/java/dk/camelot64/kickc/test/ref/immzero.asm
 create mode 100644 src/main/java/dk/camelot64/kickc/test/ref/immzero.cfg
 create mode 100644 src/main/java/dk/camelot64/kickc/test/ref/immzero.log
 create mode 100644 src/main/java/dk/camelot64/kickc/test/ref/immzero.sym

diff --git a/src/main/java/dk/camelot64/kickc/test/ref/immzero.asm b/src/main/java/dk/camelot64/kickc/test/ref/immzero.asm
new file mode 100644
index 000000000..a41a7288c
--- /dev/null
+++ b/src/main/java/dk/camelot64/kickc/test/ref/immzero.asm
@@ -0,0 +1,24 @@
+.pc = $801 "Basic"
+:BasicUpstart(main)
+.pc = $80d "Program"
+  jsr main
+main: {
+    .label w = 2
+    lda #<0
+    sta w
+    lda #>0
+    sta w+1
+    ldx #0
+  b1:
+    txa
+    clc
+    adc w
+    sta w
+    bcc !+
+    inc w+1
+  !:
+    inx
+    cpx #$b
+    bne b1
+    rts
+}
diff --git a/src/main/java/dk/camelot64/kickc/test/ref/immzero.cfg b/src/main/java/dk/camelot64/kickc/test/ref/immzero.cfg
new file mode 100644
index 000000000..5f2461971
--- /dev/null
+++ b/src/main/java/dk/camelot64/kickc/test/ref/immzero.cfg
@@ -0,0 +1,19 @@
+@begin: scope:[]  from
+  to:@1
+@1: scope:[]  from @begin
+  [0] call main param-assignment [ ] ( )
+  to:@end
+@end: scope:[]  from @1
+main: scope:[main]  from @1
+  [1] phi() [ ] ( main:0 [ ] )
+  to:main::@1
+main::@1: scope:[main]  from main main::@1
+  [2] (word) main::w#2 ← phi( main/((word))(byte/signed byte/word/signed word) 0 main::@1/(word) main::w#1 ) [ main::i#1 main::w#2 ] ( main:0 [ main::i#1 main::w#2 ] )
+  [2] (byte) main::i#1 ← phi( main/(byte/signed byte/word/signed word) 0 main::@1/(byte) main::j#1 ) [ main::i#1 main::w#2 ] ( main:0 [ main::i#1 main::w#2 ] )
+  [3] (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1 [ main::i#1 main::w#1 ] ( main:0 [ main::i#1 main::w#1 ] )
+  [4] (byte) main::j#1 ← ++ (byte) main::i#1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] )
+  [5] if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] )
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  [6] return  [ ] ( main:0 [ ] )
+  to:@return
diff --git a/src/main/java/dk/camelot64/kickc/test/ref/immzero.log b/src/main/java/dk/camelot64/kickc/test/ref/immzero.log
new file mode 100644
index 000000000..e58eb4487
--- /dev/null
+++ b/src/main/java/dk/camelot64/kickc/test/ref/immzero.log
@@ -0,0 +1,857 @@
+// Tests that immediate zero values are reused - even when assigning to words
+void main() {
+    byte i = 0;
+    word w = (word)0;
+    for ( byte j : 0..10) {
+        i = j;
+        w = w + j;
+    }
+}
+PROGRAM
+proc (void()) main()
+  (byte) main::i ← (byte/signed byte/word/signed word) 0
+  (word~) main::$0 ← ((word)) (byte/signed byte/word/signed word) 0
+  (word) main::w ← (word~) main::$0
+  (byte) main::j ← (byte/signed byte/word/signed word) 0
+main::@1:
+  (byte) main::i ← (byte) main::j
+  (word~) main::$1 ← (word) main::w + (byte) main::j
+  (word) main::w ← (word~) main::$1
+  (byte) main::j ← ++ (byte) main::j
+  (boolean~) main::$2 ← (byte) main::j != (byte/signed byte/word/signed word) 11
+  if((boolean~) main::$2) goto main::@1
+main::@return:
+  return 
+endproc // main()
+  call main 
+
+SYMBOLS
+(void()) main()
+(word~) main::$0
+(word~) main::$1
+(boolean~) main::$2
+(label) main::@1
+(label) main::@return
+(byte) main::i
+(byte) main::j
+(word) main::w
+
+INITIAL CONTROL FLOW GRAPH
+@begin: scope:[]  from
+  to:@1
+main: scope:[main]  from
+  (byte) main::i ← (byte/signed byte/word/signed word) 0
+  (word~) main::$0 ← ((word)) (byte/signed byte/word/signed word) 0
+  (word) main::w ← (word~) main::$0
+  (byte) main::j ← (byte/signed byte/word/signed word) 0
+  to:main::@1
+main::@1: scope:[main]  from main main::@1
+  (byte) main::i ← (byte) main::j
+  (word~) main::$1 ← (word) main::w + (byte) main::j
+  (word) main::w ← (word~) main::$1
+  (byte) main::j ← ++ (byte) main::j
+  (boolean~) main::$2 ← (byte) main::j != (byte/signed byte/word/signed word) 11
+  if((boolean~) main::$2) goto main::@1
+  to:main::@2
+main::@2: scope:[main]  from main::@1
+  to:main::@return
+main::@return: scope:[main]  from main::@2
+  return 
+  to:@return
+@1: scope:[]  from @begin
+  call main 
+  to:@end
+@end: scope:[]  from @1
+
+Removing empty block main::@2
+CONTROL FLOW GRAPH
+@begin: scope:[]  from
+  to:@1
+main: scope:[main]  from
+  (byte) main::i ← (byte/signed byte/word/signed word) 0
+  (word~) main::$0 ← ((word)) (byte/signed byte/word/signed word) 0
+  (word) main::w ← (word~) main::$0
+  (byte) main::j ← (byte/signed byte/word/signed word) 0
+  to:main::@1
+main::@1: scope:[main]  from main main::@1
+  (byte) main::i ← (byte) main::j
+  (word~) main::$1 ← (word) main::w + (byte) main::j
+  (word) main::w ← (word~) main::$1
+  (byte) main::j ← ++ (byte) main::j
+  (boolean~) main::$2 ← (byte) main::j != (byte/signed byte/word/signed word) 11
+  if((boolean~) main::$2) goto main::@1
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  return 
+  to:@return
+@1: scope:[]  from @begin
+  call main 
+  to:@end
+@end: scope:[]  from @1
+
+PROCEDURE MODIFY VARIABLE ANALYSIS
+
+CONTROL FLOW GRAPH WITH ASSIGNMENT CALL
+@begin: scope:[]  from
+  to:@1
+main: scope:[main]  from @1
+  (byte) main::i ← (byte/signed byte/word/signed word) 0
+  (word~) main::$0 ← ((word)) (byte/signed byte/word/signed word) 0
+  (word) main::w ← (word~) main::$0
+  (byte) main::j ← (byte/signed byte/word/signed word) 0
+  to:main::@1
+main::@1: scope:[main]  from main main::@1
+  (byte) main::i ← (byte) main::j
+  (word~) main::$1 ← (word) main::w + (byte) main::j
+  (word) main::w ← (word~) main::$1
+  (byte) main::j ← ++ (byte) main::j
+  (boolean~) main::$2 ← (byte) main::j != (byte/signed byte/word/signed word) 11
+  if((boolean~) main::$2) goto main::@1
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  return 
+  to:@return
+@1: scope:[]  from @begin
+  call main param-assignment
+  to:@2
+@2: scope:[]  from @1
+  to:@end
+@end: scope:[]  from @2
+
+Completing Phi functions...
+CONTROL FLOW GRAPH SSA
+@begin: scope:[]  from
+  to:@1
+main: scope:[main]  from @1
+  (byte) main::i#0 ← (byte/signed byte/word/signed word) 0
+  (word~) main::$0 ← ((word)) (byte/signed byte/word/signed word) 0
+  (word) main::w#0 ← (word~) main::$0
+  (byte) main::j#0 ← (byte/signed byte/word/signed word) 0
+  to:main::@1
+main::@1: scope:[main]  from main main::@1
+  (word) main::w#2 ← phi( main/(word) main::w#0 main::@1/(word) main::w#1 )
+  (byte) main::j#2 ← phi( main/(byte) main::j#0 main::@1/(byte) main::j#1 )
+  (byte) main::i#1 ← (byte) main::j#2
+  (word~) main::$1 ← (word) main::w#2 + (byte) main::j#2
+  (word) main::w#1 ← (word~) main::$1
+  (byte) main::j#1 ← ++ (byte) main::j#2
+  (boolean~) main::$2 ← (byte) main::j#1 != (byte/signed byte/word/signed word) 11
+  if((boolean~) main::$2) goto main::@1
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  return 
+  to:@return
+@1: scope:[]  from @begin
+  call main param-assignment
+  to:@2
+@2: scope:[]  from @1
+  to:@end
+@end: scope:[]  from @2
+
+CONTROL FLOW GRAPH WITH ASSIGNMENT CALL & RETURN
+@begin: scope:[]  from
+  to:@1
+main: scope:[main]  from @1
+  (byte) main::i#0 ← (byte/signed byte/word/signed word) 0
+  (word~) main::$0 ← ((word)) (byte/signed byte/word/signed word) 0
+  (word) main::w#0 ← (word~) main::$0
+  (byte) main::j#0 ← (byte/signed byte/word/signed word) 0
+  to:main::@1
+main::@1: scope:[main]  from main main::@1
+  (word) main::w#2 ← phi( main/(word) main::w#0 main::@1/(word) main::w#1 )
+  (byte) main::j#2 ← phi( main/(byte) main::j#0 main::@1/(byte) main::j#1 )
+  (byte) main::i#1 ← (byte) main::j#2
+  (word~) main::$1 ← (word) main::w#2 + (byte) main::j#2
+  (word) main::w#1 ← (word~) main::$1
+  (byte) main::j#1 ← ++ (byte) main::j#2
+  (boolean~) main::$2 ← (byte) main::j#1 != (byte/signed byte/word/signed word) 11
+  if((boolean~) main::$2) goto main::@1
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  return 
+  to:@return
+@1: scope:[]  from @begin
+  call main param-assignment
+  to:@2
+@2: scope:[]  from @1
+  to:@end
+@end: scope:[]  from @2
+
+INITIAL SSA SYMBOL TABLE
+(label) @1
+(label) @2
+(label) @begin
+(label) @end
+(void()) main()
+(word~) main::$0
+(word~) main::$1
+(boolean~) main::$2
+(label) main::@1
+(label) main::@return
+(byte) main::i
+(byte) main::i#0
+(byte) main::i#1
+(byte) main::j
+(byte) main::j#0
+(byte) main::j#1
+(byte) main::j#2
+(word) main::w
+(word) main::w#0
+(word) main::w#1
+(word) main::w#2
+
+Culled Empty Block (label) @2
+Succesful SSA optimization Pass2CullEmptyBlocks
+CONTROL FLOW GRAPH
+@begin: scope:[]  from
+  to:@1
+main: scope:[main]  from @1
+  (byte) main::i#0 ← (byte/signed byte/word/signed word) 0
+  (word~) main::$0 ← ((word)) (byte/signed byte/word/signed word) 0
+  (word) main::w#0 ← (word~) main::$0
+  (byte) main::j#0 ← (byte/signed byte/word/signed word) 0
+  to:main::@1
+main::@1: scope:[main]  from main main::@1
+  (word) main::w#2 ← phi( main/(word) main::w#0 main::@1/(word) main::w#1 )
+  (byte) main::j#2 ← phi( main/(byte) main::j#0 main::@1/(byte) main::j#1 )
+  (byte) main::i#1 ← (byte) main::j#2
+  (word~) main::$1 ← (word) main::w#2 + (byte) main::j#2
+  (word) main::w#1 ← (word~) main::$1
+  (byte) main::j#1 ← ++ (byte) main::j#2
+  (boolean~) main::$2 ← (byte) main::j#1 != (byte/signed byte/word/signed word) 11
+  if((boolean~) main::$2) goto main::@1
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  return 
+  to:@return
+@1: scope:[]  from @begin
+  call main param-assignment
+  to:@end
+@end: scope:[]  from @1
+
+Alias (word) main::w#0 = (word~) main::$0 
+Alias (byte) main::i#1 = (byte) main::j#2 
+Alias (word) main::w#1 = (word~) main::$1 
+Succesful SSA optimization Pass2AliasElimination
+CONTROL FLOW GRAPH
+@begin: scope:[]  from
+  to:@1
+main: scope:[main]  from @1
+  (byte) main::i#0 ← (byte/signed byte/word/signed word) 0
+  (word) main::w#0 ← ((word)) (byte/signed byte/word/signed word) 0
+  (byte) main::j#0 ← (byte/signed byte/word/signed word) 0
+  to:main::@1
+main::@1: scope:[main]  from main main::@1
+  (word) main::w#2 ← phi( main/(word) main::w#0 main::@1/(word) main::w#1 )
+  (byte) main::i#1 ← phi( main/(byte) main::j#0 main::@1/(byte) main::j#1 )
+  (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1
+  (byte) main::j#1 ← ++ (byte) main::i#1
+  (boolean~) main::$2 ← (byte) main::j#1 != (byte/signed byte/word/signed word) 11
+  if((boolean~) main::$2) goto main::@1
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  return 
+  to:@return
+@1: scope:[]  from @begin
+  call main param-assignment
+  to:@end
+@end: scope:[]  from @1
+
+Simple Condition (boolean~) main::$2 if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@1
+Succesful SSA optimization Pass2ConditionalJumpSimplification
+CONTROL FLOW GRAPH
+@begin: scope:[]  from
+  to:@1
+main: scope:[main]  from @1
+  (byte) main::i#0 ← (byte/signed byte/word/signed word) 0
+  (word) main::w#0 ← ((word)) (byte/signed byte/word/signed word) 0
+  (byte) main::j#0 ← (byte/signed byte/word/signed word) 0
+  to:main::@1
+main::@1: scope:[main]  from main main::@1
+  (word) main::w#2 ← phi( main/(word) main::w#0 main::@1/(word) main::w#1 )
+  (byte) main::i#1 ← phi( main/(byte) main::j#0 main::@1/(byte) main::j#1 )
+  (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1
+  (byte) main::j#1 ← ++ (byte) main::i#1
+  if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@1
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  return 
+  to:@return
+@1: scope:[]  from @begin
+  call main param-assignment
+  to:@end
+@end: scope:[]  from @1
+
+Constant (const byte) main::i#0 = 0
+Constant (const word) main::w#0 = ((word))0
+Constant (const byte) main::j#0 = 0
+Succesful SSA optimization Pass2ConstantIdentification
+CONTROL FLOW GRAPH
+@begin: scope:[]  from
+  to:@1
+main: scope:[main]  from @1
+  to:main::@1
+main::@1: scope:[main]  from main main::@1
+  (word) main::w#2 ← phi( main/(const word) main::w#0 main::@1/(word) main::w#1 )
+  (byte) main::i#1 ← phi( main/(const byte) main::j#0 main::@1/(byte) main::j#1 )
+  (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1
+  (byte) main::j#1 ← ++ (byte) main::i#1
+  if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@1
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  return 
+  to:@return
+@1: scope:[]  from @begin
+  call main param-assignment
+  to:@end
+@end: scope:[]  from @1
+
+Inlining constant with var siblings (const byte) main::i#0
+Inlining constant with var siblings (const word) main::w#0
+Inlining constant with var siblings (const word) main::w#0
+Inlining constant with var siblings (const byte) main::j#0
+Constant inlined main::i#0 = (byte/signed byte/word/signed word) 0
+Constant inlined main::j#0 = (byte/signed byte/word/signed word) 0
+Constant inlined main::w#0 = ((word))(byte/signed byte/word/signed word) 0
+Succesful SSA optimization Pass2ConstantInlining
+CONTROL FLOW GRAPH
+@begin: scope:[]  from
+  to:@1
+main: scope:[main]  from @1
+  to:main::@1
+main::@1: scope:[main]  from main main::@1
+  (word) main::w#2 ← phi( main/((word))(byte/signed byte/word/signed word) 0 main::@1/(word) main::w#1 )
+  (byte) main::i#1 ← phi( main/(byte/signed byte/word/signed word) 0 main::@1/(byte) main::j#1 )
+  (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1
+  (byte) main::j#1 ← ++ (byte) main::i#1
+  if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@1
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  return 
+  to:@return
+@1: scope:[]  from @begin
+  call main param-assignment
+  to:@end
+@end: scope:[]  from @1
+
+FINAL SYMBOL TABLE
+(label) @1
+(label) @begin
+(label) @end
+(void()) main()
+(label) main::@1
+(label) main::@return
+(byte) main::i
+(byte) main::i#1
+(byte) main::j
+(byte) main::j#1
+(word) main::w
+(word) main::w#1
+(word) main::w#2
+
+Block Sequence Planned @begin @1 @end main main::@1 main::@return 
+Added new block during phi lifting main::@3(between main::@1 and main::@1)
+Block Sequence Planned @begin @1 @end main main::@1 main::@return main::@3 
+CONTROL FLOW GRAPH - PHI LIFTED
+@begin: scope:[]  from
+  to:@1
+@1: scope:[]  from @begin
+  call main param-assignment
+  to:@end
+@end: scope:[]  from @1
+main: scope:[main]  from @1
+  to:main::@1
+main::@1: scope:[main]  from main main::@3
+  (word) main::w#2 ← phi( main/((word))(byte/signed byte/word/signed word) 0 main::@3/(word~) main::w#3 )
+  (byte) main::i#1 ← phi( main/(byte/signed byte/word/signed word) 0 main::@3/(byte~) main::j#3 )
+  (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1
+  (byte) main::j#1 ← ++ (byte) main::i#1
+  if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@3
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  return 
+  to:@return
+main::@3: scope:[main]  from main::@1
+  (byte~) main::j#3 ← (byte) main::j#1
+  (word~) main::w#3 ← (word) main::w#1
+  to:main::@1
+
+Adding NOP phi() at start of main
+CALL GRAPH
+Calls in [] to main:0 
+
+Propagating live ranges...
+Propagating live ranges...
+Propagating live ranges...
+Propagating live ranges...
+Propagating live ranges...
+CONTROL FLOW GRAPH - LIVE RANGES FOUND
+@begin: scope:[]  from
+  to:@1
+@1: scope:[]  from @begin
+  [0] call main param-assignment [ ]
+  to:@end
+@end: scope:[]  from @1
+main: scope:[main]  from @1
+  [1] phi() [ ]
+  to:main::@1
+main::@1: scope:[main]  from main main::@3
+  [2] (word) main::w#2 ← phi( main/((word))(byte/signed byte/word/signed word) 0 main::@3/(word~) main::w#3 ) [ main::i#1 main::w#2 ]
+  [2] (byte) main::i#1 ← phi( main/(byte/signed byte/word/signed word) 0 main::@3/(byte~) main::j#3 ) [ main::i#1 main::w#2 ]
+  [3] (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1 [ main::i#1 main::w#1 ]
+  [4] (byte) main::j#1 ← ++ (byte) main::i#1 [ main::w#1 main::j#1 ]
+  [5] if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@3 [ main::w#1 main::j#1 ]
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  [6] return  [ ]
+  to:@return
+main::@3: scope:[main]  from main::@1
+  [7] (byte~) main::j#3 ← (byte) main::j#1 [ main::j#3 main::w#1 ]
+  [8] (word~) main::w#3 ← (word) main::w#1 [ main::j#3 main::w#3 ]
+  to:main::@1
+
+Created 2 initial phi equivalence classes
+Coalesced [7] main::j#3 ← main::j#1
+Coalesced [8] main::w#3 ← main::w#1
+Coalesced down to 2 phi equivalence classes
+Culled Empty Block (label) main::@3
+Block Sequence Planned @begin @1 @end main main::@1 main::@return 
+Adding NOP phi() at start of main
+Propagating live ranges...
+Propagating live ranges...
+Propagating live ranges...
+CONTROL FLOW GRAPH - BEFORE EFFECTIVE LIVE RANGES
+@begin: scope:[]  from
+  to:@1
+@1: scope:[]  from @begin
+  [0] call main param-assignment [ ]
+  to:@end
+@end: scope:[]  from @1
+main: scope:[main]  from @1
+  [1] phi() [ ]
+  to:main::@1
+main::@1: scope:[main]  from main main::@1
+  [2] (word) main::w#2 ← phi( main/((word))(byte/signed byte/word/signed word) 0 main::@1/(word) main::w#1 ) [ main::i#1 main::w#2 ]
+  [2] (byte) main::i#1 ← phi( main/(byte/signed byte/word/signed word) 0 main::@1/(byte) main::j#1 ) [ main::i#1 main::w#2 ]
+  [3] (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1 [ main::i#1 main::w#1 ]
+  [4] (byte) main::j#1 ← ++ (byte) main::i#1 [ main::j#1 main::w#1 ]
+  [5] if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@1 [ main::j#1 main::w#1 ]
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  [6] return  [ ]
+  to:@return
+
+CONTROL FLOW GRAPH - PHI MEM COALESCED
+@begin: scope:[]  from
+  to:@1
+@1: scope:[]  from @begin
+  [0] call main param-assignment [ ] ( )
+  to:@end
+@end: scope:[]  from @1
+main: scope:[main]  from @1
+  [1] phi() [ ] ( main:0 [ ] )
+  to:main::@1
+main::@1: scope:[main]  from main main::@1
+  [2] (word) main::w#2 ← phi( main/((word))(byte/signed byte/word/signed word) 0 main::@1/(word) main::w#1 ) [ main::i#1 main::w#2 ] ( main:0 [ main::i#1 main::w#2 ] )
+  [2] (byte) main::i#1 ← phi( main/(byte/signed byte/word/signed word) 0 main::@1/(byte) main::j#1 ) [ main::i#1 main::w#2 ] ( main:0 [ main::i#1 main::w#2 ] )
+  [3] (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1 [ main::i#1 main::w#1 ] ( main:0 [ main::i#1 main::w#1 ] )
+  [4] (byte) main::j#1 ← ++ (byte) main::i#1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] )
+  [5] if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] )
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  [6] return  [ ] ( main:0 [ ] )
+  to:@return
+
+DOMINATORS
+@begin dominated by  @begin 
+@1 dominated by  @1 @begin 
+@end dominated by  @1 @begin @end 
+main dominated by  @1 @begin main 
+main::@1 dominated by  @1 @begin main::@1 main 
+main::@return dominated by  main::@return @1 @begin main::@1 main 
+
+Found back edge: Loop head: main::@1 tails: main::@1 blocks: null
+Populated: Loop head: main::@1 tails: main::@1 blocks: main::@1 
+NATURAL LOOPS
+Loop head: main::@1 tails: main::@1 blocks: main::@1 
+
+Found 0 loops in scope []
+Found 1 loops in scope [main]
+  Loop head: main::@1 tails: main::@1 blocks: main::@1 
+NATURAL LOOPS WITH DEPTH
+Loop head: main::@1 tails: main::@1 blocks: main::@1  depth: 1
+
+
+VARIABLE REGISTER WEIGHTS
+(void()) main()
+(byte) main::i
+(byte) main::i#1 16.5
+(byte) main::j
+(byte) main::j#1 16.5
+(word) main::w
+(word) main::w#1 7.333333333333333
+(word) main::w#2 22.0
+
+Initial phi equivalence classes
+[ main::i#1 main::j#1 ]
+[ main::w#2 main::w#1 ]
+Complete equivalence classes
+[ main::i#1 main::j#1 ]
+[ main::w#2 main::w#1 ]
+Allocated zp ZP_BYTE:2 [ main::i#1 main::j#1 ]
+Allocated zp ZP_WORD:3 [ main::w#2 main::w#1 ]
+INITIAL ASM
+//SEG0 Basic Upstart
+.pc = $801 "Basic"
+:BasicUpstart(main)
+.pc = $80d "Program"
+//SEG1 Global Constants & labels
+//SEG2 @begin
+bbegin:
+  jmp b1
+//SEG3 @1
+b1:
+//SEG4 [0] call main param-assignment [ ] ( )
+//SEG5 [1] phi from @1 to main [phi:@1->main]
+main_from_b1:
+  jsr main
+  jmp bend
+//SEG6 @end
+bend:
+//SEG7 main
+main: {
+    .label i = 2
+    .label w = 3
+    .label j = 2
+  //SEG8 [2] phi from main to main::@1 [phi:main->main::@1]
+  b1_from_main:
+  //SEG9 [2] phi (word) main::w#2 = ((word))(byte/signed byte/word/signed word) 0 [phi:main->main::@1#0] -- zpwo1=cowo1 
+    lda #<0
+    sta w
+    lda #>0
+    sta w+1
+  //SEG10 [2] phi (byte) main::i#1 = (byte/signed byte/word/signed word) 0 [phi:main->main::@1#1] -- zpby1=coby1 
+    lda #0
+    sta i
+    jmp b1
+  //SEG11 [2] phi from main::@1 to main::@1 [phi:main::@1->main::@1]
+  b1_from_b1:
+  //SEG12 [2] phi (word) main::w#2 = (word) main::w#1 [phi:main::@1->main::@1#0] -- register_copy 
+  //SEG13 [2] phi (byte) main::i#1 = (byte) main::j#1 [phi:main::@1->main::@1#1] -- register_copy 
+    jmp b1
+  //SEG14 main::@1
+  b1:
+  //SEG15 [3] (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1 [ main::i#1 main::w#1 ] ( main:0 [ main::i#1 main::w#1 ] ) -- zpwo1=zpwo1_plus_zpby1 
+    lda i
+    clc
+    adc w
+    sta w
+    bcc !+
+    inc w+1
+  !:
+  //SEG16 [4] (byte) main::j#1 ← ++ (byte) main::i#1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] ) -- zpby1=_inc_zpby1 
+    inc j
+  //SEG17 [5] if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] ) -- zpby1_neq_coby1_then_la1 
+    lda j
+    cmp #$b
+    bne b1_from_b1
+    jmp breturn
+  //SEG18 main::@return
+  breturn:
+  //SEG19 [6] return  [ ] ( main:0 [ ] )
+    rts
+}
+
+REGISTER UPLIFT POTENTIAL REGISTERS
+Statement [3] (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1 [ main::i#1 main::w#1 ] ( main:0 [ main::i#1 main::w#1 ] ) always clobbers reg byte a 
+Removing always clobbered register reg byte a as potential for zp ZP_BYTE:2 [ main::i#1 main::j#1 ]
+Statement [3] (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1 [ main::i#1 main::w#1 ] ( main:0 [ main::i#1 main::w#1 ] ) always clobbers reg byte a 
+Potential registers zp ZP_BYTE:2 [ main::i#1 main::j#1 ] : zp ZP_BYTE:2 , reg byte x , reg byte y , 
+Potential registers zp ZP_WORD:3 [ main::w#2 main::w#1 ] : zp ZP_WORD:3 , 
+
+REGISTER UPLIFT SCOPES
+Uplift Scope [main] 33: zp ZP_BYTE:2 [ main::i#1 main::j#1 ] 29.33: zp ZP_WORD:3 [ main::w#2 main::w#1 ] 
+Uplift Scope [] 
+
+Uplifting [main] best 515 combination reg byte x [ main::i#1 main::j#1 ] zp ZP_WORD:3 [ main::w#2 main::w#1 ] 
+Uplifting [] best 515 combination 
+Allocated (was zp ZP_WORD:3) zp ZP_WORD:2 [ main::w#2 main::w#1 ]
+Removing instruction jmp b1
+Removing instruction jmp bend
+Removing instruction jmp b1
+Removing instruction jmp breturn
+Succesful ASM optimization Pass5NextJumpElimination
+ASSEMBLER
+//SEG0 Basic Upstart
+.pc = $801 "Basic"
+:BasicUpstart(main)
+.pc = $80d "Program"
+//SEG1 Global Constants & labels
+//SEG2 @begin
+bbegin:
+//SEG3 @1
+b1:
+//SEG4 [0] call main param-assignment [ ] ( )
+//SEG5 [1] phi from @1 to main [phi:@1->main]
+main_from_b1:
+  jsr main
+//SEG6 @end
+bend:
+//SEG7 main
+main: {
+    .label w = 2
+  //SEG8 [2] phi from main to main::@1 [phi:main->main::@1]
+  b1_from_main:
+  //SEG9 [2] phi (word) main::w#2 = ((word))(byte/signed byte/word/signed word) 0 [phi:main->main::@1#0] -- zpwo1=cowo1 
+    lda #<0
+    sta w
+    lda #>0
+    sta w+1
+  //SEG10 [2] phi (byte) main::i#1 = (byte/signed byte/word/signed word) 0 [phi:main->main::@1#1] -- xby=coby1 
+    ldx #0
+    jmp b1
+  //SEG11 [2] phi from main::@1 to main::@1 [phi:main::@1->main::@1]
+  b1_from_b1:
+  //SEG12 [2] phi (word) main::w#2 = (word) main::w#1 [phi:main::@1->main::@1#0] -- register_copy 
+  //SEG13 [2] phi (byte) main::i#1 = (byte) main::j#1 [phi:main::@1->main::@1#1] -- register_copy 
+  //SEG14 main::@1
+  b1:
+  //SEG15 [3] (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1 [ main::i#1 main::w#1 ] ( main:0 [ main::i#1 main::w#1 ] ) -- zpwo1=zpwo1_plus_xby 
+    txa
+    clc
+    adc w
+    sta w
+    bcc !+
+    inc w+1
+  !:
+  //SEG16 [4] (byte) main::j#1 ← ++ (byte) main::i#1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] ) -- xby=_inc_xby 
+    inx
+  //SEG17 [5] if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] ) -- xby_neq_coby1_then_la1 
+    cpx #$b
+    bne b1_from_b1
+  //SEG18 main::@return
+  breturn:
+  //SEG19 [6] return  [ ] ( main:0 [ ] )
+    rts
+}
+
+Replacing label b1_from_b1 with b1
+Removing instruction bbegin:
+Removing instruction main_from_b1:
+Removing instruction b1_from_b1:
+Succesful ASM optimization Pass5RedundantLabelElimination
+ASSEMBLER
+//SEG0 Basic Upstart
+.pc = $801 "Basic"
+:BasicUpstart(main)
+.pc = $80d "Program"
+//SEG1 Global Constants & labels
+//SEG2 @begin
+//SEG3 @1
+b1:
+//SEG4 [0] call main param-assignment [ ] ( )
+//SEG5 [1] phi from @1 to main [phi:@1->main]
+  jsr main
+//SEG6 @end
+bend:
+//SEG7 main
+main: {
+    .label w = 2
+  //SEG8 [2] phi from main to main::@1 [phi:main->main::@1]
+  b1_from_main:
+  //SEG9 [2] phi (word) main::w#2 = ((word))(byte/signed byte/word/signed word) 0 [phi:main->main::@1#0] -- zpwo1=cowo1 
+    lda #<0
+    sta w
+    lda #>0
+    sta w+1
+  //SEG10 [2] phi (byte) main::i#1 = (byte/signed byte/word/signed word) 0 [phi:main->main::@1#1] -- xby=coby1 
+    ldx #0
+    jmp b1
+  //SEG11 [2] phi from main::@1 to main::@1 [phi:main::@1->main::@1]
+  //SEG12 [2] phi (word) main::w#2 = (word) main::w#1 [phi:main::@1->main::@1#0] -- register_copy 
+  //SEG13 [2] phi (byte) main::i#1 = (byte) main::j#1 [phi:main::@1->main::@1#1] -- register_copy 
+  //SEG14 main::@1
+  b1:
+  //SEG15 [3] (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1 [ main::i#1 main::w#1 ] ( main:0 [ main::i#1 main::w#1 ] ) -- zpwo1=zpwo1_plus_xby 
+    txa
+    clc
+    adc w
+    sta w
+    bcc !+
+    inc w+1
+  !:
+  //SEG16 [4] (byte) main::j#1 ← ++ (byte) main::i#1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] ) -- xby=_inc_xby 
+    inx
+  //SEG17 [5] if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] ) -- xby_neq_coby1_then_la1 
+    cpx #$b
+    bne b1
+  //SEG18 main::@return
+  breturn:
+  //SEG19 [6] return  [ ] ( main:0 [ ] )
+    rts
+}
+
+Removing instruction b1:
+Removing instruction bend:
+Removing instruction b1_from_main:
+Removing instruction breturn:
+Succesful ASM optimization Pass5UnusedLabelElimination
+ASSEMBLER
+//SEG0 Basic Upstart
+.pc = $801 "Basic"
+:BasicUpstart(main)
+.pc = $80d "Program"
+//SEG1 Global Constants & labels
+//SEG2 @begin
+//SEG3 @1
+//SEG4 [0] call main param-assignment [ ] ( )
+//SEG5 [1] phi from @1 to main [phi:@1->main]
+  jsr main
+//SEG6 @end
+//SEG7 main
+main: {
+    .label w = 2
+  //SEG8 [2] phi from main to main::@1 [phi:main->main::@1]
+  //SEG9 [2] phi (word) main::w#2 = ((word))(byte/signed byte/word/signed word) 0 [phi:main->main::@1#0] -- zpwo1=cowo1 
+    lda #<0
+    sta w
+    lda #>0
+    sta w+1
+  //SEG10 [2] phi (byte) main::i#1 = (byte/signed byte/word/signed word) 0 [phi:main->main::@1#1] -- xby=coby1 
+    ldx #0
+    jmp b1
+  //SEG11 [2] phi from main::@1 to main::@1 [phi:main::@1->main::@1]
+  //SEG12 [2] phi (word) main::w#2 = (word) main::w#1 [phi:main::@1->main::@1#0] -- register_copy 
+  //SEG13 [2] phi (byte) main::i#1 = (byte) main::j#1 [phi:main::@1->main::@1#1] -- register_copy 
+  //SEG14 main::@1
+  b1:
+  //SEG15 [3] (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1 [ main::i#1 main::w#1 ] ( main:0 [ main::i#1 main::w#1 ] ) -- zpwo1=zpwo1_plus_xby 
+    txa
+    clc
+    adc w
+    sta w
+    bcc !+
+    inc w+1
+  !:
+  //SEG16 [4] (byte) main::j#1 ← ++ (byte) main::i#1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] ) -- xby=_inc_xby 
+    inx
+  //SEG17 [5] if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] ) -- xby_neq_coby1_then_la1 
+    cpx #$b
+    bne b1
+  //SEG18 main::@return
+  //SEG19 [6] return  [ ] ( main:0 [ ] )
+    rts
+}
+
+Removing instruction jmp b1
+Succesful ASM optimization Pass5NextJumpElimination
+ASSEMBLER
+//SEG0 Basic Upstart
+.pc = $801 "Basic"
+:BasicUpstart(main)
+.pc = $80d "Program"
+//SEG1 Global Constants & labels
+//SEG2 @begin
+//SEG3 @1
+//SEG4 [0] call main param-assignment [ ] ( )
+//SEG5 [1] phi from @1 to main [phi:@1->main]
+  jsr main
+//SEG6 @end
+//SEG7 main
+main: {
+    .label w = 2
+  //SEG8 [2] phi from main to main::@1 [phi:main->main::@1]
+  //SEG9 [2] phi (word) main::w#2 = ((word))(byte/signed byte/word/signed word) 0 [phi:main->main::@1#0] -- zpwo1=cowo1 
+    lda #<0
+    sta w
+    lda #>0
+    sta w+1
+  //SEG10 [2] phi (byte) main::i#1 = (byte/signed byte/word/signed word) 0 [phi:main->main::@1#1] -- xby=coby1 
+    ldx #0
+  //SEG11 [2] phi from main::@1 to main::@1 [phi:main::@1->main::@1]
+  //SEG12 [2] phi (word) main::w#2 = (word) main::w#1 [phi:main::@1->main::@1#0] -- register_copy 
+  //SEG13 [2] phi (byte) main::i#1 = (byte) main::j#1 [phi:main::@1->main::@1#1] -- register_copy 
+  //SEG14 main::@1
+  b1:
+  //SEG15 [3] (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1 [ main::i#1 main::w#1 ] ( main:0 [ main::i#1 main::w#1 ] ) -- zpwo1=zpwo1_plus_xby 
+    txa
+    clc
+    adc w
+    sta w
+    bcc !+
+    inc w+1
+  !:
+  //SEG16 [4] (byte) main::j#1 ← ++ (byte) main::i#1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] ) -- xby=_inc_xby 
+    inx
+  //SEG17 [5] if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] ) -- xby_neq_coby1_then_la1 
+    cpx #$b
+    bne b1
+  //SEG18 main::@return
+  //SEG19 [6] return  [ ] ( main:0 [ ] )
+    rts
+}
+
+FINAL SYMBOL TABLE
+(label) @1
+(label) @begin
+(label) @end
+(void()) main()
+(label) main::@1
+(label) main::@return
+(byte) main::i
+(byte) main::i#1 reg byte x 16.5
+(byte) main::j
+(byte) main::j#1 reg byte x 16.5
+(word) main::w
+(word) main::w#1 w zp ZP_WORD:2 7.333333333333333
+(word) main::w#2 w zp ZP_WORD:2 22.0
+
+reg byte x [ main::i#1 main::j#1 ]
+zp ZP_WORD:2 [ main::w#2 main::w#1 ]
+
+FINAL CODE
+//SEG0 Basic Upstart
+.pc = $801 "Basic"
+:BasicUpstart(main)
+.pc = $80d "Program"
+//SEG1 Global Constants & labels
+//SEG2 @begin
+//SEG3 @1
+//SEG4 [0] call main param-assignment [ ] ( )
+//SEG5 [1] phi from @1 to main [phi:@1->main]
+  jsr main
+//SEG6 @end
+//SEG7 main
+main: {
+    .label w = 2
+  //SEG8 [2] phi from main to main::@1 [phi:main->main::@1]
+  //SEG9 [2] phi (word) main::w#2 = ((word))(byte/signed byte/word/signed word) 0 [phi:main->main::@1#0] -- zpwo1=cowo1 
+    lda #<0
+    sta w
+    lda #>0
+    sta w+1
+  //SEG10 [2] phi (byte) main::i#1 = (byte/signed byte/word/signed word) 0 [phi:main->main::@1#1] -- xby=coby1 
+    ldx #0
+  //SEG11 [2] phi from main::@1 to main::@1 [phi:main::@1->main::@1]
+  //SEG12 [2] phi (word) main::w#2 = (word) main::w#1 [phi:main::@1->main::@1#0] -- register_copy 
+  //SEG13 [2] phi (byte) main::i#1 = (byte) main::j#1 [phi:main::@1->main::@1#1] -- register_copy 
+  //SEG14 main::@1
+  b1:
+  //SEG15 [3] (word) main::w#1 ← (word) main::w#2 + (byte) main::i#1 [ main::i#1 main::w#1 ] ( main:0 [ main::i#1 main::w#1 ] ) -- zpwo1=zpwo1_plus_xby 
+    txa
+    clc
+    adc w
+    sta w
+    bcc !+
+    inc w+1
+  !:
+  //SEG16 [4] (byte) main::j#1 ← ++ (byte) main::i#1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] ) -- xby=_inc_xby 
+    inx
+  //SEG17 [5] if((byte) main::j#1!=(byte/signed byte/word/signed word) 11) goto main::@1 [ main::j#1 main::w#1 ] ( main:0 [ main::j#1 main::w#1 ] ) -- xby_neq_coby1_then_la1 
+    cpx #$b
+    bne b1
+  //SEG18 main::@return
+  //SEG19 [6] return  [ ] ( main:0 [ ] )
+    rts
+}
+
diff --git a/src/main/java/dk/camelot64/kickc/test/ref/immzero.sym b/src/main/java/dk/camelot64/kickc/test/ref/immzero.sym
new file mode 100644
index 000000000..96c04793d
--- /dev/null
+++ b/src/main/java/dk/camelot64/kickc/test/ref/immzero.sym
@@ -0,0 +1,16 @@
+(label) @1
+(label) @begin
+(label) @end
+(void()) main()
+(label) main::@1
+(label) main::@return
+(byte) main::i
+(byte) main::i#1 reg byte x 16.5
+(byte) main::j
+(byte) main::j#1 reg byte x 16.5
+(word) main::w
+(word) main::w#1 w zp ZP_WORD:2 7.333333333333333
+(word) main::w#2 w zp ZP_WORD:2 22.0
+
+reg byte x [ main::i#1 main::j#1 ]
+zp ZP_WORD:2 [ main::w#2 main::w#1 ]