CONTROL FLOW GRAPH SSA
@begin: scope:[]  from
  to:@1
main: scope:[main]  from @1
  (byte*) main::SCREEN#0 ← ((byte*)) (word/signed word/dword/signed dword) $400
  (byte) main::b#0 ← (byte/signed byte/word/signed word/dword/signed dword) 0
  to:main::@1
main::@1: scope:[main]  from main main::@1
  (byte) main::b#2 ← phi( main/(byte) main::b#0 main::@1/(byte) main::b#1 )
  *((byte*) main::SCREEN#0 + (byte) main::b#2) ← (byte) 'a'
  (byte) main::b#1 ← (byte) main::b#2 + rangenext(0,$a)
  (bool~) main::$0 ← (byte) main::b#1 != rangelast(0,$a)
  if((bool~) main::$0) goto main::@1
  to:main::@return
main::@return: scope:[main]  from main::@1
  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
(void()) main()
(bool~) main::$0
(label) main::@1
(label) main::@return
(byte*) main::SCREEN
(byte*) main::SCREEN#0
(byte) main::b
(byte) main::b#0
(byte) main::b#1
(byte) main::b#2

Culled Empty Block (label) @2
Successful SSA optimization Pass2CullEmptyBlocks
Simple Condition (bool~) main::$0 [6] if((byte) main::b#1!=rangelast(0,$a)) goto main::@1
Successful SSA optimization Pass2ConditionalJumpSimplification
Constant (const byte*) main::SCREEN#0 = ((byte*))$400
Constant (const byte) main::b#0 = 0
Successful SSA optimization Pass2ConstantIdentification
Resolved ranged next value main::b#1 ← ++ main::b#2 to ++
Resolved ranged comparison value if(main::b#1!=rangelast(0,$a)) goto main::@1 to (byte/signed byte/word/signed word/dword/signed dword) $b
Inlining constant with var siblings (const byte) main::b#0
Constant inlined main::b#0 = (byte/signed byte/word/signed word/dword/signed dword) 0
Successful SSA optimization Pass2ConstantInlining
Added new block during phi lifting main::@3(between main::@1 and main::@1)
Adding NOP phi() at start of @begin
Adding NOP phi() at start of @1
Adding NOP phi() at start of @end
Adding NOP phi() at start of main
CALL GRAPH
Calls in [] to main:2 

Created 1 initial phi equivalence classes
Coalesced [10] main::b#3 ← main::b#1
Coalesced down to 1 phi equivalence classes
Culled Empty Block (label) main::@3
Adding NOP phi() at start of @begin
Adding NOP phi() at start of @1
Adding NOP phi() at start of @end
Adding NOP phi() at start of main

FINAL CONTROL FLOW GRAPH
@begin: scope:[]  from
  [0] phi()
  to:@1
@1: scope:[]  from @begin
  [1] phi()
  [2] call main 
  to:@end
@end: scope:[]  from @1
  [3] phi()
main: scope:[main]  from @1
  [4] phi()
  to:main::@1
main::@1: scope:[main]  from main main::@1
  [5] (byte) main::b#2 ← phi( main/(byte/signed byte/word/signed word/dword/signed dword) 0 main::@1/(byte) main::b#1 )
  [6] *((const byte*) main::SCREEN#0 + (byte) main::b#2) ← (byte) 'a'
  [7] (byte) main::b#1 ← ++ (byte) main::b#2
  [8] if((byte) main::b#1!=(byte/signed byte/word/signed word/dword/signed dword) $b) goto main::@1
  to:main::@return
main::@return: scope:[main]  from main::@1
  [9] return 
  to:@return


VARIABLE REGISTER WEIGHTS
(void()) main()
(byte*) main::SCREEN
(byte) main::b
(byte) main::b#1 16.5
(byte) main::b#2 16.5

Initial phi equivalence classes
[ main::b#2 main::b#1 ]
Complete equivalence classes
[ main::b#2 main::b#1 ]
Allocated zp ZP_BYTE:2 [ main::b#2 main::b#1 ]

INITIAL ASM
//SEG0 File Comments
//SEG1 Basic Upstart
.pc = $801 "Basic"
:BasicUpstart(bbegin)
.pc = $80d "Program"
//SEG2 Global Constants & labels
//SEG3 @begin
bbegin:
//SEG4 [1] phi from @begin to @1 [phi:@begin->@1]
b1_from_bbegin:
  jmp b1
//SEG5 @1
b1:
//SEG6 [2] call main 
//SEG7 [4] phi from @1 to main [phi:@1->main]
main_from_b1:
  jsr main
//SEG8 [3] phi from @1 to @end [phi:@1->@end]
bend_from_b1:
  jmp bend
//SEG9 @end
bend:
//SEG10 main
main: {
    .label SCREEN = $400
    .label b = 2
  //SEG11 [5] phi from main to main::@1 [phi:main->main::@1]
  b1_from_main:
  //SEG12 [5] phi (byte) main::b#2 = (byte/signed byte/word/signed word/dword/signed dword) 0 [phi:main->main::@1#0] -- vbuz1=vbuc1 
    lda #0
    sta b
    jmp b1
  // Do some sums
  //SEG13 [5] phi from main::@1 to main::@1 [phi:main::@1->main::@1]
  b1_from_b1:
  //SEG14 [5] phi (byte) main::b#2 = (byte) main::b#1 [phi:main::@1->main::@1#0] -- register_copy 
    jmp b1
  //SEG15 main::@1
  b1:
  //SEG16 [6] *((const byte*) main::SCREEN#0 + (byte) main::b#2) ← (byte) 'a' -- pbuc1_derefidx_vbuz1=vbuc2 
    lda #'a'
    ldy b
    sta SCREEN,y
  //SEG17 [7] (byte) main::b#1 ← ++ (byte) main::b#2 -- vbuz1=_inc_vbuz1 
    inc b
  //SEG18 [8] if((byte) main::b#1!=(byte/signed byte/word/signed word/dword/signed dword) $b) goto main::@1 -- vbuz1_neq_vbuc1_then_la1 
    lda #$b
    cmp b
    bne b1_from_b1
    jmp breturn
  //SEG19 main::@return
  breturn:
  //SEG20 [9] return 
    rts
}

REGISTER UPLIFT POTENTIAL REGISTERS
Statement [6] *((const byte*) main::SCREEN#0 + (byte) main::b#2) ← (byte) 'a' [ main::b#2 ] ( main:2 [ main::b#2 ] ) always clobbers reg byte a 
Removing always clobbered register reg byte a as potential for zp ZP_BYTE:2 [ main::b#2 main::b#1 ]
Statement [6] *((const byte*) main::SCREEN#0 + (byte) main::b#2) ← (byte) 'a' [ main::b#2 ] ( main:2 [ main::b#2 ] ) always clobbers reg byte a 
Potential registers zp ZP_BYTE:2 [ main::b#2 main::b#1 ] : zp ZP_BYTE:2 , reg byte x , reg byte y , 

REGISTER UPLIFT SCOPES
Uplift Scope [main] 33: zp ZP_BYTE:2 [ main::b#2 main::b#1 ] 
Uplift Scope [] 

Uplifting [main] best 263 combination reg byte x [ main::b#2 main::b#1 ] 
Uplifting [] best 263 combination 

ASSEMBLER BEFORE OPTIMIZATION
//SEG0 File Comments
//SEG1 Basic Upstart
.pc = $801 "Basic"
:BasicUpstart(bbegin)
.pc = $80d "Program"
//SEG2 Global Constants & labels
//SEG3 @begin
bbegin:
//SEG4 [1] phi from @begin to @1 [phi:@begin->@1]
b1_from_bbegin:
  jmp b1
//SEG5 @1
b1:
//SEG6 [2] call main 
//SEG7 [4] phi from @1 to main [phi:@1->main]
main_from_b1:
  jsr main
//SEG8 [3] phi from @1 to @end [phi:@1->@end]
bend_from_b1:
  jmp bend
//SEG9 @end
bend:
//SEG10 main
main: {
    .label SCREEN = $400
  //SEG11 [5] phi from main to main::@1 [phi:main->main::@1]
  b1_from_main:
  //SEG12 [5] phi (byte) main::b#2 = (byte/signed byte/word/signed word/dword/signed dword) 0 [phi:main->main::@1#0] -- vbuxx=vbuc1 
    ldx #0
    jmp b1
  // Do some sums
  //SEG13 [5] phi from main::@1 to main::@1 [phi:main::@1->main::@1]
  b1_from_b1:
  //SEG14 [5] phi (byte) main::b#2 = (byte) main::b#1 [phi:main::@1->main::@1#0] -- register_copy 
    jmp b1
  //SEG15 main::@1
  b1:
  //SEG16 [6] *((const byte*) main::SCREEN#0 + (byte) main::b#2) ← (byte) 'a' -- pbuc1_derefidx_vbuxx=vbuc2 
    lda #'a'
    sta SCREEN,x
  //SEG17 [7] (byte) main::b#1 ← ++ (byte) main::b#2 -- vbuxx=_inc_vbuxx 
    inx
  //SEG18 [8] if((byte) main::b#1!=(byte/signed byte/word/signed word/dword/signed dword) $b) goto main::@1 -- vbuxx_neq_vbuc1_then_la1 
    cpx #$b
    bne b1_from_b1
    jmp breturn
  //SEG19 main::@return
  breturn:
  //SEG20 [9] return 
    rts
}

ASSEMBLER OPTIMIZATIONS
Removing instruction jmp b1
Removing instruction jmp bend
Removing instruction jmp b1
Removing instruction jmp breturn
Succesful ASM optimization Pass5NextJumpElimination
Replacing label b1_from_b1 with b1
Removing instruction b1_from_bbegin:
Removing instruction b1:
Removing instruction main_from_b1:
Removing instruction bend_from_b1:
Removing instruction b1_from_b1:
Succesful ASM optimization Pass5RedundantLabelElimination
Removing instruction bend:
Removing instruction b1_from_main:
Removing instruction breturn:
Succesful ASM optimization Pass5UnusedLabelElimination
Updating BasicUpstart to call main directly
Removing instruction jsr main
Succesful ASM optimization Pass5SkipBegin
Removing instruction jmp b1
Succesful ASM optimization Pass5NextJumpElimination
Removing instruction bbegin:
Succesful ASM optimization Pass5UnusedLabelElimination

FINAL SYMBOL TABLE
(label) @1
(label) @begin
(label) @end
(void()) main()
(label) main::@1
(label) main::@return
(byte*) main::SCREEN
(const byte*) main::SCREEN#0 SCREEN = ((byte*))(word/signed word/dword/signed dword) $400
(byte) main::b
(byte) main::b#1 reg byte x 16.5
(byte) main::b#2 reg byte x 16.5

reg byte x [ main::b#2 main::b#1 ]


FINAL ASSEMBLER
Score: 161

//SEG0 File Comments
//SEG1 Basic Upstart
.pc = $801 "Basic"
:BasicUpstart(main)
.pc = $80d "Program"
//SEG2 Global Constants & labels
//SEG3 @begin
//SEG4 [1] phi from @begin to @1 [phi:@begin->@1]
//SEG5 @1
//SEG6 [2] call main 
//SEG7 [4] phi from @1 to main [phi:@1->main]
//SEG8 [3] phi from @1 to @end [phi:@1->@end]
//SEG9 @end
//SEG10 main
main: {
    .label SCREEN = $400
  //SEG11 [5] phi from main to main::@1 [phi:main->main::@1]
  //SEG12 [5] phi (byte) main::b#2 = (byte/signed byte/word/signed word/dword/signed dword) 0 [phi:main->main::@1#0] -- vbuxx=vbuc1 
    ldx #0
  // Do some sums
  //SEG13 [5] phi from main::@1 to main::@1 [phi:main::@1->main::@1]
  //SEG14 [5] phi (byte) main::b#2 = (byte) main::b#1 [phi:main::@1->main::@1#0] -- register_copy 
  //SEG15 main::@1
  b1:
  //SEG16 [6] *((const byte*) main::SCREEN#0 + (byte) main::b#2) ← (byte) 'a' -- pbuc1_derefidx_vbuxx=vbuc2 
    lda #'a'
    sta SCREEN,x
  //SEG17 [7] (byte) main::b#1 ← ++ (byte) main::b#2 -- vbuxx=_inc_vbuxx 
    inx
  //SEG18 [8] if((byte) main::b#1!=(byte/signed byte/word/signed word/dword/signed dword) $b) goto main::@1 -- vbuxx_neq_vbuc1_then_la1 
    cpx #$b
    bne b1
  //SEG19 main::@return
  //SEG20 [9] return 
    rts
}