Adding pointer type conversion cast (byte*) main::screen in (byte*) main::screen ← (number) $400
Culled Empty Block (label) @1

CONTROL FLOW GRAPH SSA
@begin: scope:[]  from
  to:@2
main: scope:[main]  from @2
  (byte*) main::screen#0 ← ((byte*)) (number) $400
  (byte**~) main::$0 ← & (byte*) main::screen#0
  (byte**) main::pscreen#0 ← (byte**~) main::$0
  (byte) sub::ch#0 ← (byte) 'a'
  (byte**) sub::dst#0 ← (byte**) main::pscreen#0
  call sub 
  to:main::@1
main::@1: scope:[main]  from main
  (byte**) main::pscreen#1 ← phi( main/(byte**) main::pscreen#0 )
  (byte) sub::ch#1 ← (byte) 'b'
  (byte**) sub::dst#1 ← (byte**) main::pscreen#1
  call sub 
  to:main::@2
main::@2: scope:[main]  from main::@1
  to:main::@return
main::@return: scope:[main]  from main::@2
  return 
  to:@return
sub: scope:[sub]  from main main::@1
  (byte**) sub::dst#2 ← phi( main/(byte**) sub::dst#0 main::@1/(byte**) sub::dst#1 )
  (byte) sub::ch#2 ← phi( main/(byte) sub::ch#0 main::@1/(byte) sub::ch#1 )
  *(*((byte**) sub::dst#2)) ← (byte) sub::ch#2
  *((byte**) sub::dst#2) ← ++ *((byte**) sub::dst#2)
  to:sub::@return
sub::@return: scope:[sub]  from sub
  return 
  to:@return
@2: scope:[]  from @begin
  call main 
  to:@3
@3: scope:[]  from @2
  to:@end
@end: scope:[]  from @3

SYMBOL TABLE SSA
(label) @2
(label) @3
(label) @begin
(label) @end
(void()) main()
(byte**~) main::$0
(label) main::@1
(label) main::@2
(label) main::@return
(byte**) main::pscreen
(byte**) main::pscreen#0
(byte**) main::pscreen#1
(byte*) main::screen
(byte*) main::screen#0
(void()) sub((byte) sub::ch , (byte**) sub::dst)
(label) sub::@return
(byte) sub::ch
(byte) sub::ch#0
(byte) sub::ch#1
(byte) sub::ch#2
(byte**) sub::dst
(byte**) sub::dst#0
(byte**) sub::dst#1
(byte**) sub::dst#2

Inlining cast (byte*) main::screen#0 ← (byte*)(number) $400
Successful SSA optimization Pass2InlineCast
Simplifying constant pointer cast (byte*) 1024
Successful SSA optimization PassNCastSimplification
Alias (byte**) main::pscreen#0 = (byte**~) main::$0 (byte**) main::pscreen#1 
Successful SSA optimization Pass2AliasElimination
Constant right-side identified [1] (byte**) main::pscreen#0 ← & (byte*) main::screen#0
Successful SSA optimization Pass2ConstantRValueConsolidation
Constant (const byte**) main::pscreen#0 = &main::screen#0
Constant (const byte) sub::ch#0 = 'a'
Constant (const byte) sub::ch#1 = 'b'
Successful SSA optimization Pass2ConstantIdentification
Constant (const byte**) sub::dst#0 = main::pscreen#0
Constant (const byte**) sub::dst#1 = main::pscreen#0
Successful SSA optimization Pass2ConstantIdentification
Inlining constant with var siblings (const byte) sub::ch#0
Inlining constant with var siblings (const byte) sub::ch#1
Inlining constant with var siblings (const byte**) sub::dst#0
Inlining constant with var siblings (const byte**) sub::dst#1
Constant inlined sub::ch#1 = (byte) 'b'
Constant inlined sub::ch#0 = (byte) 'a'
Constant inlined sub::dst#1 = (const byte**) main::pscreen#0
Constant inlined sub::dst#0 = (const byte**) main::pscreen#0
Successful SSA optimization Pass2ConstantInlining
Identical Phi Values (byte**) sub::dst#2 (const byte**) main::pscreen#0
Successful SSA optimization Pass2IdenticalPhiElimination
Adding NOP phi() at start of @begin
Adding NOP phi() at start of @2
Adding NOP phi() at start of @3
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 
Calls in [main] to sub:6 sub:8 

Created 1 initial phi equivalence classes
Coalesced down to 1 phi equivalence classes
Culled Empty Block (label) @3
Culled Empty Block (label) main::@2
Renumbering block @2 to @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::@1

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] (byte*) main::screen#0 ← (byte*) 1024
  [5] call sub 
  to:main::@1
main::@1: scope:[main]  from main
  [6] phi()
  [7] call sub 
  to:main::@return
main::@return: scope:[main]  from main::@1
  [8] return 
  to:@return
sub: scope:[sub]  from main main::@1
  [9] (byte) sub::ch#2 ← phi( main/(byte) 'a' main::@1/(byte) 'b' )
  [10] *(*((const byte**) main::pscreen#0)) ← (byte) sub::ch#2
  [11] *((const byte**) main::pscreen#0) ← ++ *((const byte**) main::pscreen#0)
  to:sub::@return
sub::@return: scope:[sub]  from sub
  [12] return 
  to:@return


VARIABLE REGISTER WEIGHTS
(void()) main()
(byte**) main::pscreen
(byte*) main::screen
(byte*) main::screen#0 20.0
(void()) sub((byte) sub::ch , (byte**) sub::dst)
(byte) sub::ch
(byte) sub::ch#2 2.0
(byte**) sub::dst

Initial phi equivalence classes
[ sub::ch#2 ]
Added variable main::screen#0 to zero page equivalence class [ main::screen#0 ]
Complete equivalence classes
[ sub::ch#2 ]
[ main::screen#0 ]
Allocated zp ZP_BYTE:2 [ sub::ch#2 ]
Allocated zp ZP_WORD:3 [ main::screen#0 ]

INITIAL ASM
//SEG0 File Comments
// Tests optimization of constant pointers to pointers
//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 
  jsr main
//SEG7 [3] phi from @1 to @end [phi:@1->@end]
bend_from_b1:
  jmp bend
//SEG8 @end
bend:
//SEG9 main
main: {
    .label pscreen = screen
    .label screen = 3
  //SEG10 [4] (byte*) main::screen#0 ← (byte*) 1024 -- pbuz1=pbuc1 
    lda #<$400
    sta screen
    lda #>$400
    sta screen+1
  //SEG11 [5] call sub 
  //SEG12 [9] phi from main to sub [phi:main->sub]
  sub_from_main:
  //SEG13 [9] phi (byte) sub::ch#2 = (byte) 'a' [phi:main->sub#0] -- vbuz1=vbuc1 
    lda #'a'
    sta sub.ch
    jsr sub
  //SEG14 [6] phi from main to main::@1 [phi:main->main::@1]
  b1_from_main:
    jmp b1
  //SEG15 main::@1
  b1:
  //SEG16 [7] call sub 
  //SEG17 [9] phi from main::@1 to sub [phi:main::@1->sub]
  sub_from_b1:
  //SEG18 [9] phi (byte) sub::ch#2 = (byte) 'b' [phi:main::@1->sub#0] -- vbuz1=vbuc1 
    lda #'b'
    sta sub.ch
    jsr sub
    jmp breturn
  //SEG19 main::@return
  breturn:
  //SEG20 [8] return 
    rts
}
//SEG21 sub
// sub(byte zeropage(2) ch)
sub: {
    .label ch = 2
  //SEG22 [10] *(*((const byte**) main::pscreen#0)) ← (byte) sub::ch#2 -- _deref__deref_pptc1=vbuz1 
    lda ch
    ldy #0
    sta (main.pscreen),y
  //SEG23 [11] *((const byte**) main::pscreen#0) ← ++ *((const byte**) main::pscreen#0) -- _deref_pptc1=_inc__deref_pptc1 
    inc main.pscreen
    bne !+
    inc main.pscreen+1
  !:
    jmp breturn
  //SEG24 sub::@return
  breturn:
  //SEG25 [12] return 
    rts
}

REGISTER UPLIFT POTENTIAL REGISTERS
Statement [4] (byte*) main::screen#0 ← (byte*) 1024 [ ] ( main:2 [ ] ) always clobbers reg byte a 
Statement [10] *(*((const byte**) main::pscreen#0)) ← (byte) sub::ch#2 [ ] ( main:2::sub:5 [ ] main:2::sub:7 [ ] ) always clobbers reg byte y 
Potential registers zp ZP_BYTE:2 [ sub::ch#2 ] : zp ZP_BYTE:2 , reg byte a , reg byte x , reg byte y , 
Potential registers zp ZP_WORD:3 [ main::screen#0 ] : zp ZP_WORD:3 , 

REGISTER UPLIFT SCOPES
Uplift Scope [main] 20: zp ZP_WORD:3 [ main::screen#0 ] 
Uplift Scope [sub] 2: zp ZP_BYTE:2 [ sub::ch#2 ] 
Uplift Scope [] 

Uplifting [main] best 90 combination zp ZP_WORD:3 [ main::screen#0 ] 
Uplifting [sub] best 81 combination reg byte a [ sub::ch#2 ] 
Uplifting [] best 81 combination 
Allocated (was zp ZP_WORD:3) zp ZP_WORD:2 [ main::screen#0 ]

ASSEMBLER BEFORE OPTIMIZATION
//SEG0 File Comments
// Tests optimization of constant pointers to pointers
//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 
  jsr main
//SEG7 [3] phi from @1 to @end [phi:@1->@end]
bend_from_b1:
  jmp bend
//SEG8 @end
bend:
//SEG9 main
main: {
    .label pscreen = screen
    .label screen = 2
  //SEG10 [4] (byte*) main::screen#0 ← (byte*) 1024 -- pbuz1=pbuc1 
    lda #<$400
    sta screen
    lda #>$400
    sta screen+1
  //SEG11 [5] call sub 
  //SEG12 [9] phi from main to sub [phi:main->sub]
  sub_from_main:
  //SEG13 [9] phi (byte) sub::ch#2 = (byte) 'a' [phi:main->sub#0] -- vbuaa=vbuc1 
    lda #'a'
    jsr sub
  //SEG14 [6] phi from main to main::@1 [phi:main->main::@1]
  b1_from_main:
    jmp b1
  //SEG15 main::@1
  b1:
  //SEG16 [7] call sub 
  //SEG17 [9] phi from main::@1 to sub [phi:main::@1->sub]
  sub_from_b1:
  //SEG18 [9] phi (byte) sub::ch#2 = (byte) 'b' [phi:main::@1->sub#0] -- vbuaa=vbuc1 
    lda #'b'
    jsr sub
    jmp breturn
  //SEG19 main::@return
  breturn:
  //SEG20 [8] return 
    rts
}
//SEG21 sub
// sub(byte register(A) ch)
sub: {
  //SEG22 [10] *(*((const byte**) main::pscreen#0)) ← (byte) sub::ch#2 -- _deref__deref_pptc1=vbuaa 
    ldy #0
    sta (main.pscreen),y
  //SEG23 [11] *((const byte**) main::pscreen#0) ← ++ *((const byte**) main::pscreen#0) -- _deref_pptc1=_inc__deref_pptc1 
    inc main.pscreen
    bne !+
    inc main.pscreen+1
  !:
    jmp breturn
  //SEG24 sub::@return
  breturn:
  //SEG25 [12] return 
    rts
}

ASSEMBLER OPTIMIZATIONS
Removing instruction jmp b1
Removing instruction jmp bend
Removing instruction jmp b1
Removing instruction jmp breturn
Removing instruction jmp breturn
Succesful ASM optimization Pass5NextJumpElimination
Removing instruction b1_from_bbegin:
Removing instruction b1:
Removing instruction bend_from_b1:
Removing instruction b1_from_main:
Removing instruction sub_from_b1:
Succesful ASM optimization Pass5RedundantLabelElimination
Removing instruction bend:
Removing instruction sub_from_main:
Removing instruction b1:
Removing instruction breturn:
Removing instruction breturn:
Succesful ASM optimization Pass5UnusedLabelElimination
Updating BasicUpstart to call main directly
Removing instruction jsr main
Succesful ASM optimization Pass5SkipBegin
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::pscreen
(const byte**) main::pscreen#0 pscreen = &(byte*) main::screen#0
(byte*) main::screen
(byte*) main::screen#0 screen zp ZP_WORD:2 20.0
(void()) sub((byte) sub::ch , (byte**) sub::dst)
(label) sub::@return
(byte) sub::ch
(byte) sub::ch#2 reg byte a 2.0
(byte**) sub::dst

reg byte a [ sub::ch#2 ]
zp ZP_WORD:2 [ main::screen#0 ]


FINAL ASSEMBLER
Score: 60

//SEG0 File Comments
// Tests optimization of constant pointers to pointers
//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 [3] phi from @1 to @end [phi:@1->@end]
//SEG8 @end
//SEG9 main
main: {
    .label pscreen = screen
    .label screen = 2
  //SEG10 [4] (byte*) main::screen#0 ← (byte*) 1024 -- pbuz1=pbuc1 
    lda #<$400
    sta screen
    lda #>$400
    sta screen+1
  //SEG11 [5] call sub 
  //SEG12 [9] phi from main to sub [phi:main->sub]
  //SEG13 [9] phi (byte) sub::ch#2 = (byte) 'a' [phi:main->sub#0] -- vbuaa=vbuc1 
    lda #'a'
    jsr sub
  //SEG14 [6] phi from main to main::@1 [phi:main->main::@1]
  //SEG15 main::@1
  //SEG16 [7] call sub 
  //SEG17 [9] phi from main::@1 to sub [phi:main::@1->sub]
  //SEG18 [9] phi (byte) sub::ch#2 = (byte) 'b' [phi:main::@1->sub#0] -- vbuaa=vbuc1 
    lda #'b'
    jsr sub
  //SEG19 main::@return
  //SEG20 [8] return 
    rts
}
//SEG21 sub
// sub(byte register(A) ch)
sub: {
  //SEG22 [10] *(*((const byte**) main::pscreen#0)) ← (byte) sub::ch#2 -- _deref__deref_pptc1=vbuaa 
    ldy #0
    sta (main.pscreen),y
  //SEG23 [11] *((const byte**) main::pscreen#0) ← ++ *((const byte**) main::pscreen#0) -- _deref_pptc1=_inc__deref_pptc1 
    inc main.pscreen
    bne !+
    inc main.pscreen+1
  !:
  //SEG24 sub::@return
  //SEG25 [12] return 
    rts
}