CONTROL FLOW GRAPH SSA

void main()
main: scope:[main]  from __start
  main::i = 0
  to:main::@1
main::@1: scope:[main]  from main main::@2
  sub1::i#0 = main::i
  call sub1
  sub1::return#0 = sub1::return#2
  to:main::@2
main::@2: scope:[main]  from main::@1
  sub1::return#3 = phi( main::@1/sub1::return#0 )
  main::$0 = sub1::return#3
  main::SCREEN[main::i] = main::$0
  main::i = main::i + rangenext(0,2)
  main::$1 = main::i != rangelast(0,2)
  if(main::$1) goto main::@1
  to:main::@return
main::@return: scope:[main]  from main::@2
  return 
  to:@return

char sub1(char i)
sub1: scope:[sub1]  from main::@1
  sub1::i#1 = phi( main::@1/sub1::i#0 )
  sub1::$0 = sub1::i#1 + sub1::i#1
  sub1::return#1 = sub1::$0
  to:sub1::@return
sub1::@return: scope:[sub1]  from sub1
  sub1::return#4 = phi( sub1/sub1::return#1 )
  sub1::return#2 = sub1::return#4
  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
void __start()
void main()
char main::$0
bool main::$1
__constant char * const main::SCREEN = (char *)$400
__loadstore volatile char main::i
char sub1(char i)
char sub1::$0
char sub1::i
char sub1::i#0
char sub1::i#1
char sub1::return
char sub1::return#0
char sub1::return#1
char sub1::return#2
char sub1::return#3
char sub1::return#4

Simplifying constant pointer cast (char *) 1024
Successful SSA optimization PassNCastSimplification
Alias sub1::return#0 = sub1::return#3 
Alias sub1::return#1 = sub1::$0 sub1::return#4 sub1::return#2 
Successful SSA optimization Pass2AliasElimination
Identical Phi Values sub1::i#1 sub1::i#0
Successful SSA optimization Pass2IdenticalPhiElimination
Simple Condition main::$1 [8] if(main::i!=rangelast(0,2)) goto main::@1
Successful SSA optimization Pass2ConditionalJumpSimplification
Resolved ranged next value [6] main::i = ++ main::i to ++
Resolved ranged comparison value [8] if(main::i!=rangelast(0,2)) goto main::@1 to 3
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
Adding number conversion cast (unumber) 3 in [7] if(main::i!=3) goto main::@1
Successful SSA optimization PassNAddNumberTypeConversions
Simplifying constant integer cast 3
Successful SSA optimization PassNCastSimplification
Finalized unsigned number type (char) 3
Successful SSA optimization PassNFinalizeNumberTypeConversions
CALL GRAPH
Calls in [main] to sub1:2 

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

FINAL CONTROL FLOW GRAPH

void main()
main: scope:[main]  from
  [0] main::i = 0
  to:main::@1
main::@1: scope:[main]  from main main::@2
  [1] sub1::i#0 = main::i
  [2] call sub1
  [3] sub1::return#0 = sub1::return#1
  to:main::@2
main::@2: scope:[main]  from main::@1
  [4] main::$0 = sub1::return#0
  [5] main::SCREEN[main::i] = main::$0
  [6] main::i = ++ main::i
  [7] if(main::i!=3) goto main::@1
  to:main::@return
main::@return: scope:[main]  from main::@2
  [8] return 
  to:@return

char sub1(char i)
sub1: scope:[sub1]  from main::@1
  [9] sub1::return#1 = sub1::i#0 + sub1::i#0
  to:sub1::@return
sub1::@return: scope:[sub1]  from sub1
  [10] return 
  to:@return


VARIABLE REGISTER WEIGHTS
void main()
char main::$0 // 22.0
__loadstore volatile char main::i // 7.125
char sub1(char i)
char sub1::i
char sub1::i#0 // 213.0
char sub1::return
char sub1::return#0 // 22.0
char sub1::return#1 // 37.33333333333333

Initial phi equivalence classes
Added variable main::i to live range equivalence class [ main::i ]
Added variable sub1::i#0 to live range equivalence class [ sub1::i#0 ]
Added variable sub1::return#0 to live range equivalence class [ sub1::return#0 ]
Added variable main::$0 to live range equivalence class [ main::$0 ]
Added variable sub1::return#1 to live range equivalence class [ sub1::return#1 ]
Complete equivalence classes
[ main::i ]
[ sub1::i#0 ]
[ sub1::return#0 ]
[ main::$0 ]
[ sub1::return#1 ]
Allocated zp[1]:129 [ sub1::i#0 ]
Allocated zp[1]:130 [ sub1::return#1 ]
Allocated zp[1]:131 [ sub1::return#0 ]
Allocated zp[1]:132 [ main::$0 ]
Allocated zp[1]:133 [ main::i ]
REGISTER UPLIFT POTENTIAL REGISTERS
Statement [0] main::i = 0 [ main::i ] (  [ main::i ] { }  ) always clobbers reg byte a 
Statement [5] main::SCREEN[main::i] = main::$0 [ main::i ] (  [ main::i ] { }  ) always clobbers reg byte y 
Statement [7] if(main::i!=3) goto main::@1 [ main::i ] (  [ main::i ] { }  ) always clobbers reg byte a 
Statement [9] sub1::return#1 = sub1::i#0 + sub1::i#0 [ sub1::return#1 ] ( sub1:2 [ main::i sub1::return#1 ] { { sub1::i#0 = main::i } { sub1::return#0 = sub1::return#1 } }  ) always clobbers reg byte a 
Potential registers zp[1]:133 [ main::i ] : zp[1]:133 , 
Potential registers zp[1]:129 [ sub1::i#0 ] : zp[1]:129 , reg byte a , reg byte x , reg byte y , 
Potential registers zp[1]:131 [ sub1::return#0 ] : zp[1]:131 , reg byte a , reg byte x , reg byte y , 
Potential registers zp[1]:132 [ main::$0 ] : zp[1]:132 , reg byte a , reg byte x , reg byte y , 
Potential registers zp[1]:130 [ sub1::return#1 ] : zp[1]:130 , reg byte a , reg byte x , reg byte y , 

REGISTER UPLIFT SCOPES
Uplift Scope [sub1] 213: zp[1]:129 [ sub1::i#0 ] 37.33: zp[1]:130 [ sub1::return#1 ] 22: zp[1]:131 [ sub1::return#0 ] 
Uplift Scope [main] 22: zp[1]:132 [ main::$0 ] 7.12: zp[1]:133 [ main::i ] 
Uplift Scope [] 

Uplifting [sub1] best 440 combination reg byte a [ sub1::i#0 ] reg byte a [ sub1::return#1 ] reg byte a [ sub1::return#0 ] 
Uplifting [main] best 380 combination reg byte a [ main::$0 ] zp[1]:133 [ main::i ] 
Uplifting [] best 380 combination 
Attempting to uplift remaining variables inzp[1]:133 [ main::i ]
Uplifting [main] best 380 combination zp[1]:133 [ main::i ] 
Allocated (was zp[1]:133) zp[1]:129 [ main::i ]

ASSEMBLER BEFORE OPTIMIZATION
  // File Comments
// Demonstrates global directive reserving a range of addresses on zeropage
  // Upstart
  // Commodore 64 PRG executable file
.file [name="reserve-zp-global-range.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
.segment Code
  // main
main: {
    .label SCREEN = $400
    .label i = $81
    // [0] main::i = 0 -- vbuz1=vbuc1 
    lda #0
    sta.z i
    jmp __b1
    // main::@1
  __b1:
    // [1] sub1::i#0 = main::i -- vbuaa=vbuz1 
    lda.z i
    // [2] call sub1
    jsr sub1
    // [3] sub1::return#0 = sub1::return#1
    jmp __b2
    // main::@2
  __b2:
    // [4] main::$0 = sub1::return#0
    // [5] main::SCREEN[main::i] = main::$0 -- pbuc1_derefidx_vbuz1=vbuaa 
    ldy.z i
    sta SCREEN,y
    // [6] main::i = ++ main::i -- vbuz1=_inc_vbuz1 
    inc.z i
    // [7] if(main::i!=3) goto main::@1 -- vbuz1_neq_vbuc1_then_la1 
    lda #3
    cmp.z i
    bne __b1
    jmp __breturn
    // main::@return
  __breturn:
    // [8] return 
    rts
}
  // sub1
// __register(A) char sub1(__register(A) char i)
sub1: {
    // [9] sub1::return#1 = sub1::i#0 + sub1::i#0 -- vbuaa=vbuaa_plus_vbuaa 
    asl
    jmp __breturn
    // sub1::@return
  __breturn:
    // [10] return 
    rts
}
  // File Data

ASSEMBLER OPTIMIZATIONS
Removing instruction jmp __b1
Removing instruction jmp __b2
Removing instruction jmp __breturn
Removing instruction jmp __breturn
Succesful ASM optimization Pass5NextJumpElimination
Removing instruction __b2:
Removing instruction __breturn:
Removing instruction __breturn:
Succesful ASM optimization Pass5UnusedLabelElimination

FINAL SYMBOL TABLE
void main()
char main::$0 // reg byte a 22.0
__constant char * const main::SCREEN = (char *) 1024
__loadstore volatile char main::i // zp[1]:129 7.125
char sub1(char i)
char sub1::i
char sub1::i#0 // reg byte a 213.0
char sub1::return
char sub1::return#0 // reg byte a 22.0
char sub1::return#1 // reg byte a 37.33333333333333

zp[1]:129 [ main::i ]
reg byte a [ sub1::i#0 ]
reg byte a [ sub1::return#0 ]
reg byte a [ main::$0 ]
reg byte a [ sub1::return#1 ]


FINAL ASSEMBLER
Score: 314

  // File Comments
// Demonstrates global directive reserving a range of addresses on zeropage
  // Upstart
  // Commodore 64 PRG executable file
.file [name="reserve-zp-global-range.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
.segment Code
  // main
main: {
    .label SCREEN = $400
    .label i = $81
    // for( volatile byte i : 0..2)
    // [0] main::i = 0 -- vbuz1=vbuc1 
    lda #0
    sta.z i
    // main::@1
  __b1:
    // sub1(i)
    // [1] sub1::i#0 = main::i -- vbuaa=vbuz1 
    lda.z i
    // [2] call sub1
    jsr sub1
    // [3] sub1::return#0 = sub1::return#1
    // main::@2
    // [4] main::$0 = sub1::return#0
    // SCREEN[i] = sub1(i)
    // [5] main::SCREEN[main::i] = main::$0 -- pbuc1_derefidx_vbuz1=vbuaa 
    ldy.z i
    sta SCREEN,y
    // for( volatile byte i : 0..2)
    // [6] main::i = ++ main::i -- vbuz1=_inc_vbuz1 
    inc.z i
    // [7] if(main::i!=3) goto main::@1 -- vbuz1_neq_vbuc1_then_la1 
    lda #3
    cmp.z i
    bne __b1
    // main::@return
    // }
    // [8] return 
    rts
}
  // sub1
// __register(A) char sub1(__register(A) char i)
sub1: {
    // i+i
    // [9] sub1::return#1 = sub1::i#0 + sub1::i#0 -- vbuaa=vbuaa_plus_vbuaa 
    asl
    // sub1::@return
    // }
    // [10] return 
    rts
}
  // File Data