kickc/src/test/ref/interrupt-volatile-reuse-problem2.log

Resolved forward reference irq to interrupt(KERNEL_MIN)(void()) irq()

CONTROL FLOW GRAPH SSA
@begin: scope:[]  from
  (volatile byte) col1 ← (byte) 0
  to:@1

(void()) main()
main: scope:[main]  from @1
  *((const nomodify void()**) KERNEL_IRQ) ← &interrupt(KERNEL_MIN)(void()) irq()
  to:main::@1
main::@1: scope:[main]  from main main::@7
  if(true) goto main::@2
  to:main::@return
main::@2: scope:[main]  from main::@1
  (byte) main::x#0 ← (byte) 0
  to:main::@3
main::@3: scope:[main]  from main::@2 main::@7
  (byte) main::x#6 ← phi( main::@2/(byte) main::x#0 main::@7/(byte) main::x#1 )
  (byte) main::y#0 ← (byte) 0
  to:main::@4
main::@4: scope:[main]  from main::@3 main::@6
  (byte) main::x#4 ← phi( main::@3/(byte) main::x#6 main::@6/(byte) main::x#5 )
  (byte) main::y#4 ← phi( main::@3/(byte) main::y#0 main::@6/(byte) main::y#1 )
  (byte) main::a#0 ← (byte) 0
  to:main::@5
main::@5: scope:[main]  from main::@4 main::@5
  (byte) main::x#2 ← phi( main::@4/(byte) main::x#4 main::@5/(byte) main::x#2 )
  (byte) main::y#2 ← phi( main::@4/(byte) main::y#4 main::@5/(byte) main::y#2 )
  (byte) main::a#2 ← phi( main::@4/(byte) main::a#0 main::@5/(byte) main::a#1 )
  (byte~) main::$0 ← (byte) main::a#2 + (byte) main::y#2
  *((const nomodify byte*) SCREEN + (byte) main::x#2) ← (byte~) main::$0
  (byte) main::a#1 ← (byte) main::a#2 + rangenext(0,$a)
  (bool~) main::$1 ← (byte) main::a#1 != rangelast(0,$a)
  if((bool~) main::$1) goto main::@5
  to:main::@6
main::@6: scope:[main]  from main::@5
  (byte) main::x#5 ← phi( main::@5/(byte) main::x#2 )
  (byte) main::y#3 ← phi( main::@5/(byte) main::y#2 )
  (byte) main::y#1 ← (byte) main::y#3 + rangenext(0,$a)
  (bool~) main::$2 ← (byte) main::y#1 != rangelast(0,$a)
  if((bool~) main::$2) goto main::@4
  to:main::@7
main::@7: scope:[main]  from main::@6
  (byte) main::x#3 ← phi( main::@6/(byte) main::x#5 )
  (byte) main::x#1 ← (byte) main::x#3 + rangenext(0,$a)
  (bool~) main::$3 ← (byte) main::x#1 != rangelast(0,$a)
  if((bool~) main::$3) goto main::@3
  to:main::@1
main::@return: scope:[main]  from main::@1
  return 
  to:@return

interrupt(KERNEL_MIN)(void()) irq()
irq: scope:[irq]  from
  *((const nomodify byte*) IRQ_STATUS) ← (number) 1
  asm { lda$dc0d  }
  *((const nomodify byte*) SCREEN + (number) $28) ← (volatile byte) col1
  (volatile byte) col1 ← ++ (volatile byte) col1
  to:irq::@return
irq::@return: scope:[irq]  from irq
  return 
  to:@return
@1: scope:[]  from @begin
  call main 
  to:@2
@2: scope:[]  from @1
  to:@end
@end: scope:[]  from @2

SYMBOL TABLE SSA
(label) @1
(label) @2
(label) @begin
(label) @end
(const nomodify byte*) IRQ_STATUS = (byte*)(number) $d019
(const nomodify void()**) KERNEL_IRQ = (void()**)(number) $314
(const nomodify byte*) SCREEN = (byte*)(number) $400
(volatile byte) col1 loadstore
interrupt(KERNEL_MIN)(void()) irq()
(label) irq::@return
(void()) main()
(byte~) main::$0
(bool~) main::$1
(bool~) main::$2
(bool~) main::$3
(label) main::@1
(label) main::@2
(label) main::@3
(label) main::@4
(label) main::@5
(label) main::@6
(label) main::@7
(label) main::@return
(byte) main::a
(byte) main::a#0
(byte) main::a#1
(byte) main::a#2
(byte) main::x
(byte) main::x#0
(byte) main::x#1
(byte) main::x#2
(byte) main::x#3
(byte) main::x#4
(byte) main::x#5
(byte) main::x#6
(byte) main::y
(byte) main::y#0
(byte) main::y#1
(byte) main::y#2
(byte) main::y#3
(byte) main::y#4

Adding number conversion cast (unumber) 1 in *((const nomodify byte*) IRQ_STATUS) ← (number) 1
Adding number conversion cast (unumber) $28 in *((const nomodify byte*) SCREEN + (number) $28) ← (volatile byte) col1
Successful SSA optimization PassNAddNumberTypeConversions
Inlining cast *((const nomodify byte*) IRQ_STATUS) ← (unumber)(number) 1
Successful SSA optimization Pass2InlineCast
Simplifying constant pointer cast (void()**) 788
Simplifying constant pointer cast (byte*) 53273
Simplifying constant pointer cast (byte*) 1024
Simplifying constant integer cast 1
Simplifying constant integer cast $28
Successful SSA optimization PassNCastSimplification
Finalized unsigned number type (byte) 1
Finalized unsigned number type (byte) $28
Successful SSA optimization PassNFinalizeNumberTypeConversions
Alias main::y#2 = main::y#3 
Alias main::x#2 = main::x#5 main::x#3 
Successful SSA optimization Pass2AliasElimination
Identical Phi Values (byte) main::y#2 (byte) main::y#4
Identical Phi Values (byte) main::x#2 (byte) main::x#4
Successful SSA optimization Pass2IdenticalPhiElimination
Identical Phi Values (byte) main::x#4 (byte) main::x#6
Successful SSA optimization Pass2IdenticalPhiElimination
Simple Condition (bool~) main::$1 [13] if((byte) main::a#1!=rangelast(0,$a)) goto main::@5
Simple Condition (bool~) main::$2 [16] if((byte) main::y#1!=rangelast(0,$a)) goto main::@4
Simple Condition (bool~) main::$3 [19] if((byte) main::x#1!=rangelast(0,$a)) goto main::@3
Successful SSA optimization Pass2ConditionalJumpSimplification
Constant (const byte) main::x#0 = 0
Constant (const byte) main::y#0 = 0
Constant (const byte) main::a#0 = 0
Successful SSA optimization Pass2ConstantIdentification
if() condition always true - replacing block destination [2] if(true) goto main::@2
Successful SSA optimization Pass2ConstantIfs
Resolved ranged next value [11] main::a#1 ← ++ main::a#2 to ++
Resolved ranged comparison value [13] if(main::a#1!=rangelast(0,$a)) goto main::@5 to (number) $b
Resolved ranged next value [14] main::y#1 ← ++ main::y#4 to ++
Resolved ranged comparison value [16] if(main::y#1!=rangelast(0,$a)) goto main::@4 to (number) $b
Resolved ranged next value [17] main::x#1 ← ++ main::x#6 to ++
Resolved ranged comparison value [19] if(main::x#1!=rangelast(0,$a)) goto main::@3 to (number) $b
Removing unused block main::@return
Successful SSA optimization Pass2EliminateUnusedBlocks
Adding number conversion cast (unumber) $b in if((byte) main::a#1!=(number) $b) goto main::@5
Adding number conversion cast (unumber) $b in if((byte) main::y#1!=(number) $b) goto main::@4
Adding number conversion cast (unumber) $b in if((byte) main::x#1!=(number) $b) goto main::@3
Successful SSA optimization PassNAddNumberTypeConversions
Simplifying constant integer cast $b
Simplifying constant integer cast $b
Simplifying constant integer cast $b
Successful SSA optimization PassNCastSimplification
Finalized unsigned number type (byte) $b
Finalized unsigned number type (byte) $b
Finalized unsigned number type (byte) $b
Successful SSA optimization PassNFinalizeNumberTypeConversions
Inlining constant with var siblings (const byte) main::x#0
Inlining constant with var siblings (const byte) main::y#0
Inlining constant with var siblings (const byte) main::a#0
Constant inlined main::a#0 = (byte) 0
Constant inlined main::x#0 = (byte) 0
Constant inlined main::y#0 = (byte) 0
Successful SSA optimization Pass2ConstantInlining
Consolidated array index constant in *(SCREEN+$28)
Successful SSA optimization Pass2ConstantAdditionElimination
Added new block during phi lifting main::@8(between main::@7 and main::@3)
Added new block during phi lifting main::@9(between main::@6 and main::@4)
Added new block during phi lifting main::@10(between main::@5 and main::@5)
Adding NOP phi() at start of @1
Adding NOP phi() at start of @2
Adding NOP phi() at start of @end
Adding NOP phi() at start of main::@1
Adding NOP phi() at start of main::@2
CALL GRAPH
Calls in [] to main:2 

Created 3 initial phi equivalence classes
Coalesced [19] main::x#7 ← main::x#1
Coalesced [20] main::y#5 ← main::y#1
Coalesced [21] main::a#3 ← main::a#1
Coalesced down to 3 phi equivalence classes
Culled Empty Block (label) @2
Culled Empty Block (label) main::@1
Culled Empty Block (label) main::@2
Culled Empty Block (label) main::@9
Culled Empty Block (label) main::@10
Renumbering block main::@3 to main::@1
Renumbering block main::@4 to main::@2
Renumbering block main::@5 to main::@3
Renumbering block main::@6 to main::@4
Renumbering block main::@7 to main::@5
Renumbering block main::@8 to main::@6
Adding NOP phi() at start of @1
Adding NOP phi() at start of @end
Adding NOP phi() at start of main::@6

FINAL CONTROL FLOW GRAPH
@begin: scope:[]  from
  [0] (volatile byte) col1 ← (byte) 0
  to:@1
@1: scope:[]  from @begin
  [1] phi()
  [2] call main 
  to:@end
@end: scope:[]  from @1
  [3] phi()

(void()) main()
main: scope:[main]  from @1
  [4] *((const nomodify void()**) KERNEL_IRQ) ← &interrupt(KERNEL_MIN)(void()) irq()
  to:main::@1
main::@1: scope:[main]  from main main::@5 main::@6
  [5] (byte) main::x#6 ← phi( main/(byte) 0 main::@6/(byte) main::x#1 main::@5/(byte) 0 )
  to:main::@2
main::@2: scope:[main]  from main::@1 main::@4
  [6] (byte) main::y#4 ← phi( main::@1/(byte) 0 main::@4/(byte) main::y#1 )
  to:main::@3
main::@3: scope:[main]  from main::@2 main::@3
  [7] (byte) main::a#2 ← phi( main::@2/(byte) 0 main::@3/(byte) main::a#1 )
  [8] (byte~) main::$0 ← (byte) main::a#2 + (byte) main::y#4
  [9] *((const nomodify byte*) SCREEN + (byte) main::x#6) ← (byte~) main::$0
  [10] (byte) main::a#1 ← ++ (byte) main::a#2
  [11] if((byte) main::a#1!=(byte) $b) goto main::@3
  to:main::@4
main::@4: scope:[main]  from main::@3
  [12] (byte) main::y#1 ← ++ (byte) main::y#4
  [13] if((byte) main::y#1!=(byte) $b) goto main::@2
  to:main::@5
main::@5: scope:[main]  from main::@4
  [14] (byte) main::x#1 ← ++ (byte) main::x#6
  [15] if((byte) main::x#1!=(byte) $b) goto main::@6
  to:main::@1
main::@6: scope:[main]  from main::@5
  [16] phi()
  to:main::@1

interrupt(KERNEL_MIN)(void()) irq()
irq: scope:[irq]  from
  [17] *((const nomodify byte*) IRQ_STATUS) ← (byte) 1
  asm { lda$dc0d  }
  [19] *((const nomodify byte*) SCREEN+(byte) $28) ← (volatile byte) col1
  [20] (volatile byte) col1 ← ++ (volatile byte) col1
  to:irq::@return
irq::@return: scope:[irq]  from irq
  [21] return 
  to:@return


VARIABLE REGISTER WEIGHTS
(volatile byte) col1 loadstore 2.6666666666666665
interrupt(KERNEL_MIN)(void()) irq()
(void()) main()
(byte~) main::$0 200002.0
(byte) main::a
(byte) main::a#1 150001.5
(byte) main::a#2 100001.0
(byte) main::x
(byte) main::x#1 701.0
(byte) main::x#6 11233.666666666668
(byte) main::y
(byte) main::y#1 15001.5
(byte) main::y#4 20000.499999999996

Initial phi equivalence classes
[ main::x#6 main::x#1 ]
[ main::y#4 main::y#1 ]
[ main::a#2 main::a#1 ]
Added variable col1 to live range equivalence class [ col1 ]
Added variable main::$0 to live range equivalence class [ main::$0 ]
Complete equivalence classes
[ main::x#6 main::x#1 ]
[ main::y#4 main::y#1 ]
[ main::a#2 main::a#1 ]
[ col1 ]
[ main::$0 ]
Allocated zp[1]:2 [ main::x#6 main::x#1 ]
Allocated zp[1]:3 [ main::y#4 main::y#1 ]
Allocated zp[1]:4 [ main::a#2 main::a#1 ]
Allocated zp[1]:5 [ col1 ]
Allocated zp[1]:6 [ main::$0 ]

INITIAL ASM
Target platform is c64basic / MOS6502X
  // File Comments
// Illustrates problem where volatiles reuse ZP addresses of other variables
  // Upstart
.pc = $801 "Basic"
:BasicUpstart(__bbegin)
.pc = $80d "Program"
  // Global Constants & labels
  .label KERNEL_IRQ = $314
  .label IRQ_STATUS = $d019
  .label SCREEN = $400
  .label col1 = 5
  // @begin
__bbegin:
  // [0] (volatile byte) col1 ← (byte) 0 -- vbuz1=vbuc1 
  lda #0
  sta.z col1
  // [1] phi from @begin to @1 [phi:@begin->@1]
__b1_from___bbegin:
  jmp __b1
  // @1
__b1:
  // [2] call main 
  jsr main
  // [3] phi from @1 to @end [phi:@1->@end]
__bend_from___b1:
  jmp __bend
  // @end
__bend:
  // main
main: {
    .label __0 = 6
    .label a = 4
    .label y = 3
    .label x = 2
    // [4] *((const nomodify void()**) KERNEL_IRQ) ← &interrupt(KERNEL_MIN)(void()) irq() -- _deref_pptc1=pprc2 
    lda #<irq
    sta KERNEL_IRQ
    lda #>irq
    sta KERNEL_IRQ+1
    // [5] phi from main main::@5 to main::@1 [phi:main/main::@5->main::@1]
  __b1_from_main:
  __b1_from___b5:
    // [5] phi (byte) main::x#6 = (byte) 0 [phi:main/main::@5->main::@1#0] -- vbuz1=vbuc1 
    lda #0
    sta.z x
    jmp __b1
    // main::@1
  __b1:
    // [6] phi from main::@1 to main::@2 [phi:main::@1->main::@2]
  __b2_from___b1:
    // [6] phi (byte) main::y#4 = (byte) 0 [phi:main::@1->main::@2#0] -- vbuz1=vbuc1 
    lda #0
    sta.z y
    jmp __b2
    // [6] phi from main::@4 to main::@2 [phi:main::@4->main::@2]
  __b2_from___b4:
    // [6] phi (byte) main::y#4 = (byte) main::y#1 [phi:main::@4->main::@2#0] -- register_copy 
    jmp __b2
    // main::@2
  __b2:
    // [7] phi from main::@2 to main::@3 [phi:main::@2->main::@3]
  __b3_from___b2:
    // [7] phi (byte) main::a#2 = (byte) 0 [phi:main::@2->main::@3#0] -- vbuz1=vbuc1 
    lda #0
    sta.z a
    jmp __b3
    // [7] phi from main::@3 to main::@3 [phi:main::@3->main::@3]
  __b3_from___b3:
    // [7] phi (byte) main::a#2 = (byte) main::a#1 [phi:main::@3->main::@3#0] -- register_copy 
    jmp __b3
    // main::@3
  __b3:
    // [8] (byte~) main::$0 ← (byte) main::a#2 + (byte) main::y#4 -- vbuz1=vbuz2_plus_vbuz3 
    lda.z a
    clc
    adc.z y
    sta.z __0
    // [9] *((const nomodify byte*) SCREEN + (byte) main::x#6) ← (byte~) main::$0 -- pbuc1_derefidx_vbuz1=vbuz2 
    lda.z __0
    ldy.z x
    sta SCREEN,y
    // [10] (byte) main::a#1 ← ++ (byte) main::a#2 -- vbuz1=_inc_vbuz1 
    inc.z a
    // [11] if((byte) main::a#1!=(byte) $b) goto main::@3 -- vbuz1_neq_vbuc1_then_la1 
    lda #$b
    cmp.z a
    bne __b3_from___b3
    jmp __b4
    // main::@4
  __b4:
    // [12] (byte) main::y#1 ← ++ (byte) main::y#4 -- vbuz1=_inc_vbuz1 
    inc.z y
    // [13] if((byte) main::y#1!=(byte) $b) goto main::@2 -- vbuz1_neq_vbuc1_then_la1 
    lda #$b
    cmp.z y
    bne __b2_from___b4
    jmp __b5
    // main::@5
  __b5:
    // [14] (byte) main::x#1 ← ++ (byte) main::x#6 -- vbuz1=_inc_vbuz1 
    inc.z x
    // [15] if((byte) main::x#1!=(byte) $b) goto main::@6 -- vbuz1_neq_vbuc1_then_la1 
    lda #$b
    cmp.z x
    bne __b6_from___b5
    jmp __b1_from___b5
    // [16] phi from main::@5 to main::@6 [phi:main::@5->main::@6]
  __b6_from___b5:
    jmp __b6
    // main::@6
  __b6:
    // [5] phi from main::@6 to main::@1 [phi:main::@6->main::@1]
  __b1_from___b6:
    // [5] phi (byte) main::x#6 = (byte) main::x#1 [phi:main::@6->main::@1#0] -- register_copy 
    jmp __b1
}
  // irq
irq: {
    // entry interrupt(KERNEL_MIN)
    // [17] *((const nomodify byte*) IRQ_STATUS) ← (byte) 1 -- _deref_pbuc1=vbuc2 
    // Acknowledge the IRQ
    lda #1
    sta IRQ_STATUS
    // asm { lda$dc0d  }
    lda $dc0d
    // [19] *((const nomodify byte*) SCREEN+(byte) $28) ← (volatile byte) col1 -- _deref_pbuc1=vbuz1 
    lda.z col1
    sta SCREEN+$28
    // [20] (volatile byte) col1 ← ++ (volatile byte) col1 -- vbuz1=_inc_vbuz1 
    inc.z col1
    jmp __breturn
    // irq::@return
  __breturn:
    // [21] return  - exit interrupt(KERNEL_MIN)
    jmp $ea81
}
  // File Data

REGISTER UPLIFT POTENTIAL REGISTERS
Statement [0] (volatile byte) col1 ← (byte) 0 [ ] (  [ ] { }  ) always clobbers reg byte a 
Statement [4] *((const nomodify void()**) KERNEL_IRQ) ← &interrupt(KERNEL_MIN)(void()) irq() [ ] ( main:2 [ ] { }  ) always clobbers reg byte a 
Statement [8] (byte~) main::$0 ← (byte) main::a#2 + (byte) main::y#4 [ main::x#6 main::y#4 main::a#2 main::$0 ] ( main:2 [ main::x#6 main::y#4 main::a#2 main::$0 ] { }  ) always clobbers reg byte a 
Removing always clobbered register reg byte a as potential for zp[1]:2 [ main::x#6 main::x#1 ]
Removing always clobbered register reg byte a as potential for zp[1]:3 [ main::y#4 main::y#1 ]
Removing always clobbered register reg byte a as potential for zp[1]:4 [ main::a#2 main::a#1 ]
Statement [17] *((const nomodify byte*) IRQ_STATUS) ← (byte) 1 [ col1 ] (  [ col1 ] { }  ) always clobbers reg byte a 
Statement asm { lda$dc0d  } always clobbers reg byte a 
Statement [19] *((const nomodify byte*) SCREEN+(byte) $28) ← (volatile byte) col1 [ col1 ] (  [ col1 ] { }  ) always clobbers reg byte a 
Statement [0] (volatile byte) col1 ← (byte) 0 [ ] (  [ ] { }  ) always clobbers reg byte a 
Statement [4] *((const nomodify void()**) KERNEL_IRQ) ← &interrupt(KERNEL_MIN)(void()) irq() [ ] ( main:2 [ ] { }  ) always clobbers reg byte a 
Statement [8] (byte~) main::$0 ← (byte) main::a#2 + (byte) main::y#4 [ main::x#6 main::y#4 main::a#2 main::$0 ] ( main:2 [ main::x#6 main::y#4 main::a#2 main::$0 ] { }  ) always clobbers reg byte a 
Statement [17] *((const nomodify byte*) IRQ_STATUS) ← (byte) 1 [ col1 ] (  [ col1 ] { }  ) always clobbers reg byte a 
Statement asm { lda$dc0d  } always clobbers reg byte a 
Statement [19] *((const nomodify byte*) SCREEN+(byte) $28) ← (volatile byte) col1 [ col1 ] (  [ col1 ] { }  ) always clobbers reg byte a 
Potential registers zp[1]:2 [ main::x#6 main::x#1 ] : zp[1]:2 , reg byte x , reg byte y , 
Potential registers zp[1]:3 [ main::y#4 main::y#1 ] : zp[1]:3 , reg byte x , reg byte y , 
Potential registers zp[1]:4 [ main::a#2 main::a#1 ] : zp[1]:4 , reg byte x , reg byte y , 
Potential registers zp[1]:5 [ col1 ] : zp[1]:5 , 
Potential registers zp[1]:6 [ main::$0 ] : zp[1]:6 , reg byte a , reg byte x , reg byte y , 

REGISTER UPLIFT SCOPES
Uplift Scope [main] 250,002.5: zp[1]:4 [ main::a#2 main::a#1 ] 200,002: zp[1]:6 [ main::$0 ] 35,002: zp[1]:3 [ main::y#4 main::y#1 ] 11,934.67: zp[1]:2 [ main::x#6 main::x#1 ] 
Uplift Scope [] 2.67: zp[1]:5 [ col1 ] 
Uplift Scope [irq] 

Uplifting [main] best 323337 combination reg byte y [ main::a#2 main::a#1 ] reg byte a [ main::$0 ] zp[1]:3 [ main::y#4 main::y#1 ] reg byte x [ main::x#6 main::x#1 ] 
Limited combination testing to 100 combinations of 108 possible.
Uplifting [] best 323337 combination zp[1]:5 [ col1 ] 
Uplifting [irq] best 323337 combination 
Attempting to uplift remaining variables inzp[1]:3 [ main::y#4 main::y#1 ]
Uplifting [main] best 323337 combination zp[1]:3 [ main::y#4 main::y#1 ] 
Attempting to uplift remaining variables inzp[1]:5 [ col1 ]
Uplifting [] best 323337 combination zp[1]:5 [ col1 ] 
Allocated (was zp[1]:3) zp[1]:2 [ main::y#4 main::y#1 ]
Allocated (was zp[1]:5) zp[1]:3 [ col1 ]

ASSEMBLER BEFORE OPTIMIZATION
  // File Comments
// Illustrates problem where volatiles reuse ZP addresses of other variables
  // Upstart
.pc = $801 "Basic"
:BasicUpstart(__bbegin)
.pc = $80d "Program"
  // Global Constants & labels
  .label KERNEL_IRQ = $314
  .label IRQ_STATUS = $d019
  .label SCREEN = $400
  .label col1 = 3
  // @begin
__bbegin:
  // [0] (volatile byte) col1 ← (byte) 0 -- vbuz1=vbuc1 
  lda #0
  sta.z col1
  // [1] phi from @begin to @1 [phi:@begin->@1]
__b1_from___bbegin:
  jmp __b1
  // @1
__b1:
  // [2] call main 
  jsr main
  // [3] phi from @1 to @end [phi:@1->@end]
__bend_from___b1:
  jmp __bend
  // @end
__bend:
  // main
main: {
    .label y = 2
    // [4] *((const nomodify void()**) KERNEL_IRQ) ← &interrupt(KERNEL_MIN)(void()) irq() -- _deref_pptc1=pprc2 
    lda #<irq
    sta KERNEL_IRQ
    lda #>irq
    sta KERNEL_IRQ+1
    // [5] phi from main main::@5 to main::@1 [phi:main/main::@5->main::@1]
  __b1_from_main:
  __b1_from___b5:
    // [5] phi (byte) main::x#6 = (byte) 0 [phi:main/main::@5->main::@1#0] -- vbuxx=vbuc1 
    ldx #0
    jmp __b1
    // main::@1
  __b1:
    // [6] phi from main::@1 to main::@2 [phi:main::@1->main::@2]
  __b2_from___b1:
    // [6] phi (byte) main::y#4 = (byte) 0 [phi:main::@1->main::@2#0] -- vbuz1=vbuc1 
    lda #0
    sta.z y
    jmp __b2
    // [6] phi from main::@4 to main::@2 [phi:main::@4->main::@2]
  __b2_from___b4:
    // [6] phi (byte) main::y#4 = (byte) main::y#1 [phi:main::@4->main::@2#0] -- register_copy 
    jmp __b2
    // main::@2
  __b2:
    // [7] phi from main::@2 to main::@3 [phi:main::@2->main::@3]
  __b3_from___b2:
    // [7] phi (byte) main::a#2 = (byte) 0 [phi:main::@2->main::@3#0] -- vbuyy=vbuc1 
    ldy #0
    jmp __b3
    // [7] phi from main::@3 to main::@3 [phi:main::@3->main::@3]
  __b3_from___b3:
    // [7] phi (byte) main::a#2 = (byte) main::a#1 [phi:main::@3->main::@3#0] -- register_copy 
    jmp __b3
    // main::@3
  __b3:
    // [8] (byte~) main::$0 ← (byte) main::a#2 + (byte) main::y#4 -- vbuaa=vbuyy_plus_vbuz1 
    tya
    clc
    adc.z y
    // [9] *((const nomodify byte*) SCREEN + (byte) main::x#6) ← (byte~) main::$0 -- pbuc1_derefidx_vbuxx=vbuaa 
    sta SCREEN,x
    // [10] (byte) main::a#1 ← ++ (byte) main::a#2 -- vbuyy=_inc_vbuyy 
    iny
    // [11] if((byte) main::a#1!=(byte) $b) goto main::@3 -- vbuyy_neq_vbuc1_then_la1 
    cpy #$b
    bne __b3_from___b3
    jmp __b4
    // main::@4
  __b4:
    // [12] (byte) main::y#1 ← ++ (byte) main::y#4 -- vbuz1=_inc_vbuz1 
    inc.z y
    // [13] if((byte) main::y#1!=(byte) $b) goto main::@2 -- vbuz1_neq_vbuc1_then_la1 
    lda #$b
    cmp.z y
    bne __b2_from___b4
    jmp __b5
    // main::@5
  __b5:
    // [14] (byte) main::x#1 ← ++ (byte) main::x#6 -- vbuxx=_inc_vbuxx 
    inx
    // [15] if((byte) main::x#1!=(byte) $b) goto main::@6 -- vbuxx_neq_vbuc1_then_la1 
    cpx #$b
    bne __b6_from___b5
    jmp __b1_from___b5
    // [16] phi from main::@5 to main::@6 [phi:main::@5->main::@6]
  __b6_from___b5:
    jmp __b6
    // main::@6
  __b6:
    // [5] phi from main::@6 to main::@1 [phi:main::@6->main::@1]
  __b1_from___b6:
    // [5] phi (byte) main::x#6 = (byte) main::x#1 [phi:main::@6->main::@1#0] -- register_copy 
    jmp __b1
}
  // irq
irq: {
    // entry interrupt(KERNEL_MIN)
    // [17] *((const nomodify byte*) IRQ_STATUS) ← (byte) 1 -- _deref_pbuc1=vbuc2 
    // Acknowledge the IRQ
    lda #1
    sta IRQ_STATUS
    // asm { lda$dc0d  }
    lda $dc0d
    // [19] *((const nomodify byte*) SCREEN+(byte) $28) ← (volatile byte) col1 -- _deref_pbuc1=vbuz1 
    lda.z col1
    sta SCREEN+$28
    // [20] (volatile byte) col1 ← ++ (volatile byte) col1 -- vbuz1=_inc_vbuz1 
    inc.z col1
    jmp __breturn
    // irq::@return
  __breturn:
    // [21] return  - exit interrupt(KERNEL_MIN)
    jmp $ea81
}
  // File Data

ASSEMBLER OPTIMIZATIONS
Removing instruction jmp __b1
Removing instruction jmp __bend
Removing instruction jmp __b1
Removing instruction jmp __b2
Removing instruction jmp __b3
Removing instruction jmp __b4
Removing instruction jmp __b5
Removing instruction jmp __b6
Removing instruction jmp __breturn
Succesful ASM optimization Pass5NextJumpElimination
Replacing label __b3_from___b3 with __b3
Replacing label __b2_from___b4 with __b2
Replacing label __b6_from___b5 with __b6
Removing instruction __b1_from___bbegin:
Removing instruction __bend_from___b1:
Removing instruction __b1_from_main:
Removing instruction __b2_from___b1:
Removing instruction __b2_from___b4:
Removing instruction __b3_from___b2:
Removing instruction __b3_from___b3:
Removing instruction __b6_from___b5:
Removing instruction __b1_from___b6:
Succesful ASM optimization Pass5RedundantLabelElimination
Removing instruction __b1:
Removing instruction __bend:
Removing instruction __b4:
Removing instruction __b5:
Removing instruction __breturn:
Succesful ASM optimization Pass5UnusedLabelElimination
Skipping double jump to __b1 in bne __b6
Succesful ASM optimization Pass5DoubleJumpElimination
Relabelling long label __b1_from___b5 to __b4
Succesful ASM optimization Pass5RelabelLongLabels
Adding RTS to root block 
Succesful ASM optimization Pass5AddMainRts
Removing instruction jmp __b2
Removing instruction jmp __b3
Succesful ASM optimization Pass5NextJumpElimination
Removing instruction __b6:
Succesful ASM optimization Pass5UnusedLabelElimination
Removing unreachable instruction jmp __b1
Succesful ASM optimization Pass5UnreachableCodeElimination

FINAL SYMBOL TABLE
(label) @1
(label) @begin
(label) @end
(const nomodify byte*) IRQ_STATUS = (byte*) 53273
(const nomodify void()**) KERNEL_IRQ = (void()**) 788
(const nomodify byte*) SCREEN = (byte*) 1024
(volatile byte) col1 loadstore zp[1]:3 2.6666666666666665
interrupt(KERNEL_MIN)(void()) irq()
(label) irq::@return
(void()) main()
(byte~) main::$0 reg byte a 200002.0
(label) main::@1
(label) main::@2
(label) main::@3
(label) main::@4
(label) main::@5
(label) main::@6
(byte) main::a
(byte) main::a#1 reg byte y 150001.5
(byte) main::a#2 reg byte y 100001.0
(byte) main::x
(byte) main::x#1 reg byte x 701.0
(byte) main::x#6 reg byte x 11233.666666666668
(byte) main::y
(byte) main::y#1 y zp[1]:2 15001.5
(byte) main::y#4 y zp[1]:2 20000.499999999996

reg byte x [ main::x#6 main::x#1 ]
zp[1]:2 [ main::y#4 main::y#1 ]
reg byte y [ main::a#2 main::a#1 ]
zp[1]:3 [ col1 ]
reg byte a [ main::$0 ]


FINAL ASSEMBLER
Score: 223704

  // File Comments
// Illustrates problem where volatiles reuse ZP addresses of other variables
  // Upstart
.pc = $801 "Basic"
:BasicUpstart(__bbegin)
.pc = $80d "Program"
  // Global Constants & labels
  .label KERNEL_IRQ = $314
  .label IRQ_STATUS = $d019
  .label SCREEN = $400
  .label col1 = 3
  // @begin
__bbegin:
  // col1 = 0
  // [0] (volatile byte) col1 ← (byte) 0 -- vbuz1=vbuc1 
  lda #0
  sta.z col1
  // [1] phi from @begin to @1 [phi:@begin->@1]
  // @1
  // [2] call main 
  jsr main
  rts
  // [3] phi from @1 to @end [phi:@1->@end]
  // @end
  // main
main: {
    .label y = 2
    // *KERNEL_IRQ = &irq
    // [4] *((const nomodify void()**) KERNEL_IRQ) ← &interrupt(KERNEL_MIN)(void()) irq() -- _deref_pptc1=pprc2 
    lda #<irq
    sta KERNEL_IRQ
    lda #>irq
    sta KERNEL_IRQ+1
    // [5] phi from main main::@5 to main::@1 [phi:main/main::@5->main::@1]
  __b4:
    // [5] phi (byte) main::x#6 = (byte) 0 [phi:main/main::@5->main::@1#0] -- vbuxx=vbuc1 
    ldx #0
    // main::@1
  __b1:
    // [6] phi from main::@1 to main::@2 [phi:main::@1->main::@2]
    // [6] phi (byte) main::y#4 = (byte) 0 [phi:main::@1->main::@2#0] -- vbuz1=vbuc1 
    lda #0
    sta.z y
    // [6] phi from main::@4 to main::@2 [phi:main::@4->main::@2]
    // [6] phi (byte) main::y#4 = (byte) main::y#1 [phi:main::@4->main::@2#0] -- register_copy 
    // main::@2
  __b2:
    // [7] phi from main::@2 to main::@3 [phi:main::@2->main::@3]
    // [7] phi (byte) main::a#2 = (byte) 0 [phi:main::@2->main::@3#0] -- vbuyy=vbuc1 
    ldy #0
    // [7] phi from main::@3 to main::@3 [phi:main::@3->main::@3]
    // [7] phi (byte) main::a#2 = (byte) main::a#1 [phi:main::@3->main::@3#0] -- register_copy 
    // main::@3
  __b3:
    // a+y
    // [8] (byte~) main::$0 ← (byte) main::a#2 + (byte) main::y#4 -- vbuaa=vbuyy_plus_vbuz1 
    tya
    clc
    adc.z y
    // SCREEN[x] = a+y
    // [9] *((const nomodify byte*) SCREEN + (byte) main::x#6) ← (byte~) main::$0 -- pbuc1_derefidx_vbuxx=vbuaa 
    sta SCREEN,x
    // for (byte a:0..10)
    // [10] (byte) main::a#1 ← ++ (byte) main::a#2 -- vbuyy=_inc_vbuyy 
    iny
    // [11] if((byte) main::a#1!=(byte) $b) goto main::@3 -- vbuyy_neq_vbuc1_then_la1 
    cpy #$b
    bne __b3
    // main::@4
    // for(byte y: 0..10)
    // [12] (byte) main::y#1 ← ++ (byte) main::y#4 -- vbuz1=_inc_vbuz1 
    inc.z y
    // [13] if((byte) main::y#1!=(byte) $b) goto main::@2 -- vbuz1_neq_vbuc1_then_la1 
    lda #$b
    cmp.z y
    bne __b2
    // main::@5
    // for(byte x: 0..10)
    // [14] (byte) main::x#1 ← ++ (byte) main::x#6 -- vbuxx=_inc_vbuxx 
    inx
    // [15] if((byte) main::x#1!=(byte) $b) goto main::@6 -- vbuxx_neq_vbuc1_then_la1 
    cpx #$b
    bne __b1
    jmp __b4
    // [16] phi from main::@5 to main::@6 [phi:main::@5->main::@6]
    // main::@6
    // [5] phi from main::@6 to main::@1 [phi:main::@6->main::@1]
    // [5] phi (byte) main::x#6 = (byte) main::x#1 [phi:main::@6->main::@1#0] -- register_copy 
}
  // irq
irq: {
    // entry interrupt(KERNEL_MIN)
    // *IRQ_STATUS = 1
    // [17] *((const nomodify byte*) IRQ_STATUS) ← (byte) 1 -- _deref_pbuc1=vbuc2 
    // Acknowledge the IRQ
    lda #1
    sta IRQ_STATUS
    // asm
    // asm { lda$dc0d  }
    lda $dc0d
    // SCREEN[40] = col1++
    // [19] *((const nomodify byte*) SCREEN+(byte) $28) ← (volatile byte) col1 -- _deref_pbuc1=vbuz1 
    lda.z col1
    sta SCREEN+$28
    // SCREEN[40] = col1++;
    // [20] (volatile byte) col1 ← ++ (volatile byte) col1 -- vbuz1=_inc_vbuz1 
    inc.z col1
    // irq::@return
    // }
    // [21] return  - exit interrupt(KERNEL_MIN)
    jmp $ea81
}
  // File Data