CONTROL FLOW GRAPH SSA

void main()
main: scope:[main]  from __start
  *((unsigned int *)&data+OFFSET_UNION_DATA_W) = $1234
  main::$0 = byte1  *((unsigned int *)&data+OFFSET_UNION_DATA_W)
  SCREEN[0] = main::$0
  main::$1 = byte0  *((unsigned int *)&data+OFFSET_UNION_DATA_W)
  SCREEN[1] = main::$1
  to:main::@return
main::@return: scope:[main]  from main
  return 
  to:@return

void __start()
__start: scope:[__start]  from
  call main
  to:__start::@1
__start::@1: scope:[__start]  from __start
  to:__start::@return
__start::@return: scope:[__start]  from __start::@1
  return 
  to:@return

SYMBOL TABLE SSA
__constant char OFFSET_UNION_DATA_W = 0
__constant char * const SCREEN = (char *)$400
void __start()
__loadstore union Data data = { b: $c }
void main()
char main::$0
char main::$1

Adding number conversion cast (unumber) $1234 in *((unsigned int *)&data+OFFSET_UNION_DATA_W) = $1234
Adding number conversion cast (unumber) 0 in SCREEN[0] = main::$0
Adding number conversion cast (unumber) 1 in SCREEN[1] = main::$1
Successful SSA optimization PassNAddNumberTypeConversions
Inlining cast *((unsigned int *)&data+OFFSET_UNION_DATA_W) = (unumber)$1234
Successful SSA optimization Pass2InlineCast
Simplifying constant pointer cast (char *) 1024
Simplifying constant integer cast $1234
Simplifying constant integer cast 0
Simplifying constant integer cast 1
Successful SSA optimization PassNCastSimplification
Finalized unsigned number type (unsigned int) $1234
Finalized unsigned number type (char) 0
Finalized unsigned number type (char) 1
Successful SSA optimization PassNFinalizeNumberTypeConversions
Simplifying expression containing zero (unsigned int *)&data in [0] *((unsigned int *)&data+OFFSET_UNION_DATA_W) = $1234
Simplifying expression containing zero (unsigned int *)&data in [1] main::$0 = byte1  *((unsigned int *)&data+OFFSET_UNION_DATA_W)
Simplifying expression containing zero SCREEN in [2] SCREEN[0] = main::$0
Simplifying expression containing zero (unsigned int *)&data in [3] main::$1 = byte0  *((unsigned int *)&data+OFFSET_UNION_DATA_W)
Successful SSA optimization PassNSimplifyExpressionWithZero
Eliminating unused constant OFFSET_UNION_DATA_W
Successful SSA optimization PassNEliminateUnusedVars
Removing unused procedure __start
Removing unused procedure block __start
Removing unused procedure block __start::@1
Removing unused procedure block __start::@return
Successful SSA optimization PassNEliminateEmptyStart
Consolidated array index constant in *(SCREEN+1)
Successful SSA optimization Pass2ConstantAdditionElimination
CALL GRAPH

Created 0 initial phi equivalence classes
Coalesced down to 0 phi equivalence classes

FINAL CONTROL FLOW GRAPH

void main()
main: scope:[main]  from
  [0] *((unsigned int *)&data) = $1234
  [1] main::$0 = byte1  *((unsigned int *)&data)
  [2] *SCREEN = main::$0
  [3] main::$1 = byte0  *((unsigned int *)&data)
  [4] *(SCREEN+1) = main::$1
  to:main::@return
main::@return: scope:[main]  from main
  [5] return 
  to:@return


VARIABLE REGISTER WEIGHTS
__loadstore union Data data = { b: $c }
void main()
char main::$0 // 4.0
char main::$1 // 4.0

Initial phi equivalence classes
Added variable main::$0 to live range equivalence class [ main::$0 ]
Added variable main::$1 to live range equivalence class [ main::$1 ]
Added variable data to live range equivalence class [ data ]
Complete equivalence classes
[ main::$0 ]
[ main::$1 ]
[ data ]
Allocated zp[1]:2 [ main::$0 ]
Allocated zp[1]:3 [ main::$1 ]
Allocated mem[2] [ data ]
REGISTER UPLIFT POTENTIAL REGISTERS
Statement [0] *((unsigned int *)&data) = $1234 [ data ] (  [ data ] { }  ) always clobbers reg byte a 
Potential registers zp[1]:2 [ main::$0 ] : zp[1]:2 , reg byte a , reg byte x , reg byte y , 
Potential registers zp[1]:3 [ main::$1 ] : zp[1]:3 , reg byte a , reg byte x , reg byte y , 
Potential registers mem[2] [ data ] : mem[2] , 

REGISTER UPLIFT SCOPES
Uplift Scope [main] 4: zp[1]:2 [ main::$0 ] 4: zp[1]:3 [ main::$1 ] 
Uplift Scope [Data] 
Uplift Scope [] 0: mem[2] [ data ] 

Uplifting [main] best 37 combination reg byte a [ main::$0 ] reg byte a [ main::$1 ] 
Uplifting [Data] best 37 combination 
Uplifting [] best 37 combination mem[2] [ data ] 

ASSEMBLER BEFORE OPTIMIZATION
  // File Comments
// Minimal union with C-Standard behavior - union initializer with first element smaller than second
  // Upstart
  // Commodore 64 PRG executable file
.file [name="union-6.prg", type="prg", segments="Program"]
.segmentdef Program [segments="Basic, Code, Data"]
.segmentdef Basic [start=$0801]
.segmentdef Code [start=$80d]
.segmentdef Data [startAfter="Code"]
.segment Basic
:BasicUpstart(main)
  // Global Constants & labels
  .label SCREEN = $400
.segment Code
  // main
main: {
    // [0] *((unsigned int *)&data) = $1234 -- _deref_pwuc1=vwuc2 
    lda #<$1234
    sta data
    lda #>$1234
    sta data+1
    // [1] main::$0 = byte1  *((unsigned int *)&data) -- vbuaa=_byte1__deref_pwuc1 
    lda data+1
    // [2] *SCREEN = main::$0 -- _deref_pbuc1=vbuaa 
    sta SCREEN
    // [3] main::$1 = byte0  *((unsigned int *)&data) -- vbuaa=_byte0__deref_pwuc1 
    lda data
    // [4] *(SCREEN+1) = main::$1 -- _deref_pbuc1=vbuaa 
    sta SCREEN+1
    jmp __breturn
    // main::@return
  __breturn:
    // [5] return 
    rts
}
  // File Data
.segment Data
  data: .byte $c
  .fill 1, 0

ASSEMBLER OPTIMIZATIONS
Removing instruction jmp __breturn
Succesful ASM optimization Pass5NextJumpElimination
Removing instruction lda data+1
Succesful ASM optimization Pass5UnnecesaryLoadElimination
Removing instruction __breturn:
Succesful ASM optimization Pass5UnusedLabelElimination

FINAL SYMBOL TABLE
__constant char * const SCREEN = (char *) 1024
__loadstore union Data data = { b: $c } // mem[2]
void main()
char main::$0 // reg byte a 4.0
char main::$1 // reg byte a 4.0

reg byte a [ main::$0 ]
reg byte a [ main::$1 ]
mem[2] [ data ]


FINAL ASSEMBLER
Score: 30

  // File Comments
// Minimal union with C-Standard behavior - union initializer with first element smaller than second
  // Upstart
  // Commodore 64 PRG executable file
.file [name="union-6.prg", type="prg", segments="Program"]
.segmentdef Program [segments="Basic, Code, Data"]
.segmentdef Basic [start=$0801]
.segmentdef Code [start=$80d]
.segmentdef Data [startAfter="Code"]
.segment Basic
:BasicUpstart(main)
  // Global Constants & labels
  .label SCREEN = $400
.segment Code
  // main
main: {
    // data.w = 0x1234
    // [0] *((unsigned int *)&data) = $1234 -- _deref_pwuc1=vwuc2 
    lda #<$1234
    sta data
    lda #>$1234
    sta data+1
    // BYTE1(data.w)
    // [1] main::$0 = byte1  *((unsigned int *)&data) -- vbuaa=_byte1__deref_pwuc1 
    // SCREEN[0] = BYTE1(data.w)
    // [2] *SCREEN = main::$0 -- _deref_pbuc1=vbuaa 
    sta SCREEN
    // BYTE0(data.w)
    // [3] main::$1 = byte0  *((unsigned int *)&data) -- vbuaa=_byte0__deref_pwuc1 
    lda data
    // SCREEN[1] = BYTE0(data.w)
    // [4] *(SCREEN+1) = main::$1 -- _deref_pbuc1=vbuaa 
    sta SCREEN+1
    // main::@return
    // }
    // [5] return 
    rts
}
  // File Data
.segment Data
  data: .byte $c
  .fill 1, 0