Added a few tests of volatile keyword.

src/test/java/dk/camelot64/kickc/test/TestPrograms.java

@@ -37,6 +37,16 @@ public class TestPrograms {
    public TestPrograms() {
    }
 
+   @Test
+   public void testVolatile1() throws IOException, URISyntaxException {
+      compileAndCompare("volatile-1");
+   }
+
+   @Test
+   public void testVolatile0() throws IOException, URISyntaxException {
+      compileAndCompare("volatile-0");
+   }
+
    @Test
    public void testNomodify5() throws IOException, URISyntaxException {
       assertError("nomodify-5", "const variable may not be modified");

src/test/kc/volatile-0.kc

@@ -0,0 +1,10 @@
+// Test that volatile vars are turned into load/store
+
+volatile char i = 3;
+
+const char* SCREEN = 0x0400;
+
+void main() {
+    while(i<7)
+        SCREEN[i++] = i;
+}

src/test/kc/volatile-1.kc

@@ -0,0 +1,9 @@
+// Test that volatile vars are turned into load/store
+
+const char* SCREEN = 0x0400;
+
+void main() {
+    volatile char i = 3;
+    while(i<7)
+        SCREEN[i++] = i;
+}

src/test/ref/volatile-0.asm

@@ -0,0 +1,24 @@
+// Test that volatile vars are turned into load/store
+.pc = $801 "Basic"
+:BasicUpstart(__bbegin)
+.pc = $80d "Program"
+  .label SCREEN = $400
+  .label i = 2
+__bbegin:
+  lda #3
+  sta.z i
+  jsr main
+  rts
+main: {
+  __b1:
+    lda.z i
+    cmp #7
+    bcc __b2
+    rts
+  __b2:
+    ldy.z i
+    tya
+    sta SCREEN,y
+    inc.z i
+    jmp __b1
+}

src/test/ref/volatile-0.cfg

@@ -0,0 +1,24 @@
+@begin: scope:[]  from
+  [0] (byte) i ← (byte) 3
+  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] phi()
+  to:main::@1
+main::@1: scope:[main]  from main main::@2
+  [5] if((byte) i<(byte) 7) goto main::@2
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  [6] return 
+  to:@return
+main::@2: scope:[main]  from main::@1
+  [7] *((const byte*) SCREEN + (byte) i) ← (byte) i
+  [8] (byte) i ← ++ (byte) i
+  to:main::@1

src/test/ref/volatile-0.log

@@ -0,0 +1,319 @@
+Culled Empty Block (label) main::@4
+Culled Empty Block (label) main::@3
+Culled Empty Block (label) main::@5
+Culled Empty Block (label) main::@6
+
+CONTROL FLOW GRAPH SSA
+@begin: scope:[]  from
+  (byte) i ← (number) 3
+  to:@1
+
+(void()) main()
+main: scope:[main]  from @1
+  to:main::@1
+main::@1: scope:[main]  from main main::@2
+  (bool~) main::$0 ← (byte) i < (number) 7
+  if((bool~) main::$0) goto main::@2
+  to:main::@return
+main::@2: scope:[main]  from main::@1
+  *((const byte*) SCREEN + (byte) i) ← (byte) i
+  (byte) i ← ++ (byte) i
+  to:main::@1
+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
+(const byte*) SCREEN = (byte*)(number) $400
+(byte) i loadstore
+(void()) main()
+(bool~) main::$0
+(label) main::@1
+(label) main::@2
+(label) main::@return
+
+Adding number conversion cast (unumber) 3 in (byte) i ← (number) 3
+Adding number conversion cast (unumber) 7 in (bool~) main::$0 ← (byte) i < (number) 7
+Successful SSA optimization PassNAddNumberTypeConversions
+Inlining cast (byte) i ← (unumber)(number) 3
+Successful SSA optimization Pass2InlineCast
+Simplifying constant pointer cast (byte*) 1024
+Simplifying constant integer cast 3
+Simplifying constant integer cast 7
+Successful SSA optimization PassNCastSimplification
+Finalized unsigned number type (byte) 3
+Finalized unsigned number type (byte) 7
+Successful SSA optimization PassNFinalizeNumberTypeConversions
+Simple Condition (bool~) main::$0 [2] if((byte) i<(byte) 7) goto main::@2
+Successful SSA optimization Pass2ConditionalJumpSimplification
+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
+CALL GRAPH
+Calls in [] to main:2 
+
+Created 0 initial phi equivalence classes
+Coalesced down to 0 phi equivalence classes
+Culled Empty Block (label) @2
+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] (byte) i ← (byte) 3
+  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] phi()
+  to:main::@1
+main::@1: scope:[main]  from main main::@2
+  [5] if((byte) i<(byte) 7) goto main::@2
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  [6] return 
+  to:@return
+main::@2: scope:[main]  from main::@1
+  [7] *((const byte*) SCREEN + (byte) i) ← (byte) i
+  [8] (byte) i ← ++ (byte) i
+  to:main::@1
+
+
+VARIABLE REGISTER WEIGHTS
+(byte) i loadstore 11.400000000000002
+(void()) main()
+
+Initial phi equivalence classes
+Added variable i to live range equivalence class [ i ]
+Complete equivalence classes
+[ i ]
+Allocated zp[1]:2 [ i ]
+
+INITIAL ASM
+Target platform is c64basic / MOS6502X
+  // File Comments
+// Test that volatile vars are turned into load/store
+  // Upstart
+.pc = $801 "Basic"
+:BasicUpstart(__bbegin)
+.pc = $80d "Program"
+  // Global Constants & labels
+  .label SCREEN = $400
+  .label i = 2
+  // @begin
+__bbegin:
+  // [0] (byte) i ← (byte) 3 -- vbuz1=vbuc1 
+  lda #3
+  sta.z i
+  // [1] phi from @begin to @1 [phi:@begin->@1]
+__b1_from___bbegin:
+  jmp __b1
+  // @1
+__b1:
+  // [2] call main 
+  // [4] phi from @1 to main [phi:@1->main]
+main_from___b1:
+  jsr main
+  // [3] phi from @1 to @end [phi:@1->@end]
+__bend_from___b1:
+  jmp __bend
+  // @end
+__bend:
+  // main
+main: {
+    jmp __b1
+    // main::@1
+  __b1:
+    // [5] if((byte) i<(byte) 7) goto main::@2 -- vbuz1_lt_vbuc1_then_la1 
+    lda.z i
+    cmp #7
+    bcc __b2
+    jmp __breturn
+    // main::@return
+  __breturn:
+    // [6] return 
+    rts
+    // main::@2
+  __b2:
+    // [7] *((const byte*) SCREEN + (byte) i) ← (byte) i -- pbuc1_derefidx_vbuz1=vbuz1 
+    ldy.z i
+    tya
+    sta SCREEN,y
+    // [8] (byte) i ← ++ (byte) i -- vbuz1=_inc_vbuz1 
+    inc.z i
+    jmp __b1
+}
+  // File Data
+
+REGISTER UPLIFT POTENTIAL REGISTERS
+Statement [0] (byte) i ← (byte) 3 [ i ] (  [ i ] ) always clobbers reg byte a 
+Statement [5] if((byte) i<(byte) 7) goto main::@2 [ i ] ( main:2 [ i ] ) always clobbers reg byte a 
+Statement [7] *((const byte*) SCREEN + (byte) i) ← (byte) i [ ] ( main:2 [ ] ) always clobbers reg byte a reg byte y 
+Potential registers zp[1]:2 [ i ] : zp[1]:2 , 
+
+REGISTER UPLIFT SCOPES
+Uplift Scope [] 11.4: zp[1]:2 [ i ] 
+Uplift Scope [main] 
+
+Uplifting [] best 338 combination zp[1]:2 [ i ] 
+Uplifting [main] best 338 combination 
+Attempting to uplift remaining variables inzp[1]:2 [ i ]
+Uplifting [] best 338 combination zp[1]:2 [ i ] 
+
+ASSEMBLER BEFORE OPTIMIZATION
+  // File Comments
+// Test that volatile vars are turned into load/store
+  // Upstart
+.pc = $801 "Basic"
+:BasicUpstart(__bbegin)
+.pc = $80d "Program"
+  // Global Constants & labels
+  .label SCREEN = $400
+  .label i = 2
+  // @begin
+__bbegin:
+  // [0] (byte) i ← (byte) 3 -- vbuz1=vbuc1 
+  lda #3
+  sta.z i
+  // [1] phi from @begin to @1 [phi:@begin->@1]
+__b1_from___bbegin:
+  jmp __b1
+  // @1
+__b1:
+  // [2] call main 
+  // [4] phi from @1 to main [phi:@1->main]
+main_from___b1:
+  jsr main
+  // [3] phi from @1 to @end [phi:@1->@end]
+__bend_from___b1:
+  jmp __bend
+  // @end
+__bend:
+  // main
+main: {
+    jmp __b1
+    // main::@1
+  __b1:
+    // [5] if((byte) i<(byte) 7) goto main::@2 -- vbuz1_lt_vbuc1_then_la1 
+    lda.z i
+    cmp #7
+    bcc __b2
+    jmp __breturn
+    // main::@return
+  __breturn:
+    // [6] return 
+    rts
+    // main::@2
+  __b2:
+    // [7] *((const byte*) SCREEN + (byte) i) ← (byte) i -- pbuc1_derefidx_vbuz1=vbuz1 
+    ldy.z i
+    tya
+    sta SCREEN,y
+    // [8] (byte) i ← ++ (byte) i -- vbuz1=_inc_vbuz1 
+    inc.z i
+    jmp __b1
+}
+  // File Data
+
+ASSEMBLER OPTIMIZATIONS
+Removing instruction jmp __b1
+Removing instruction jmp __bend
+Removing instruction jmp __b1
+Removing instruction jmp __breturn
+Succesful ASM optimization Pass5NextJumpElimination
+Removing instruction __b1_from___bbegin:
+Removing instruction main_from___b1:
+Removing instruction __bend_from___b1:
+Succesful ASM optimization Pass5RedundantLabelElimination
+Removing instruction __b1:
+Removing instruction __bend:
+Removing instruction __breturn:
+Succesful ASM optimization Pass5UnusedLabelElimination
+Adding RTS to root block 
+Succesful ASM optimization Pass5AddMainRts
+
+FINAL SYMBOL TABLE
+(label) @1
+(label) @begin
+(label) @end
+(const byte*) SCREEN = (byte*) 1024
+(byte) i loadstore zp[1]:2 11.400000000000002
+(void()) main()
+(label) main::@1
+(label) main::@2
+(label) main::@return
+
+zp[1]:2 [ i ]
+
+
+FINAL ASSEMBLER
+Score: 278
+
+  // File Comments
+// Test that volatile vars are turned into load/store
+  // Upstart
+.pc = $801 "Basic"
+:BasicUpstart(__bbegin)
+.pc = $80d "Program"
+  // Global Constants & labels
+  .label SCREEN = $400
+  .label i = 2
+  // @begin
+__bbegin:
+  // i = 3
+  // [0] (byte) i ← (byte) 3 -- vbuz1=vbuc1 
+  lda #3
+  sta.z i
+  // [1] phi from @begin to @1 [phi:@begin->@1]
+  // @1
+  // [2] call main 
+  // [4] phi from @1 to main [phi:@1->main]
+  jsr main
+  rts
+  // [3] phi from @1 to @end [phi:@1->@end]
+  // @end
+  // main
+main: {
+    // main::@1
+  __b1:
+    // while(i<7)
+    // [5] if((byte) i<(byte) 7) goto main::@2 -- vbuz1_lt_vbuc1_then_la1 
+    lda.z i
+    cmp #7
+    bcc __b2
+    // main::@return
+    // }
+    // [6] return 
+    rts
+    // main::@2
+  __b2:
+    // SCREEN[i++] = i
+    // [7] *((const byte*) SCREEN + (byte) i) ← (byte) i -- pbuc1_derefidx_vbuz1=vbuz1 
+    ldy.z i
+    tya
+    sta SCREEN,y
+    // SCREEN[i++] = i;
+    // [8] (byte) i ← ++ (byte) i -- vbuz1=_inc_vbuz1 
+    inc.z i
+    jmp __b1
+}
+  // File Data
+

src/test/ref/volatile-0.sym

@@ -0,0 +1,11 @@
+(label) @1
+(label) @begin
+(label) @end
+(const byte*) SCREEN = (byte*) 1024
+(byte) i loadstore zp[1]:2 11.400000000000002
+(void()) main()
+(label) main::@1
+(label) main::@2
+(label) main::@return
+
+zp[1]:2 [ i ]

src/test/ref/volatile-1.asm

@@ -0,0 +1,21 @@
+// Test that volatile vars are turned into load/store
+.pc = $801 "Basic"
+:BasicUpstart(main)
+.pc = $80d "Program"
+  .label SCREEN = $400
+main: {
+    .label i = 2
+    lda #3
+    sta.z i
+  __b1:
+    lda.z i
+    cmp #7
+    bcc __b2
+    rts
+  __b2:
+    ldy.z i
+    tya
+    sta SCREEN,y
+    inc.z i
+    jmp __b1
+}

src/test/ref/volatile-1.cfg

@@ -0,0 +1,24 @@
+@begin: scope:[]  from
+  [0] phi()
+  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] (byte) main::i ← (byte) 3
+  to:main::@1
+main::@1: scope:[main]  from main main::@2
+  [5] if((byte) main::i<(byte) 7) goto main::@2
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  [6] return 
+  to:@return
+main::@2: scope:[main]  from main::@1
+  [7] *((const byte*) SCREEN + (byte) main::i) ← (byte) main::i
+  [8] (byte) main::i ← ++ (byte) main::i
+  to:main::@1

src/test/ref/volatile-1.log

@@ -0,0 +1,314 @@
+Culled Empty Block (label) main::@4
+Culled Empty Block (label) main::@3
+Culled Empty Block (label) main::@5
+Culled Empty Block (label) main::@6
+
+CONTROL FLOW GRAPH SSA
+@begin: scope:[]  from
+  to:@1
+
+(void()) main()
+main: scope:[main]  from @1
+  (byte) main::i ← (number) 3
+  to:main::@1
+main::@1: scope:[main]  from main main::@2
+  (bool~) main::$0 ← (byte) main::i < (number) 7
+  if((bool~) main::$0) goto main::@2
+  to:main::@return
+main::@2: scope:[main]  from main::@1
+  *((const byte*) SCREEN + (byte) main::i) ← (byte) main::i
+  (byte) main::i ← ++ (byte) main::i
+  to:main::@1
+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
+(const byte*) SCREEN = (byte*)(number) $400
+(void()) main()
+(bool~) main::$0
+(label) main::@1
+(label) main::@2
+(label) main::@return
+(byte) main::i loadstore
+
+Adding number conversion cast (unumber) 3 in (byte) main::i ← (number) 3
+Adding number conversion cast (unumber) 7 in (bool~) main::$0 ← (byte) main::i < (number) 7
+Successful SSA optimization PassNAddNumberTypeConversions
+Inlining cast (byte) main::i ← (unumber)(number) 3
+Successful SSA optimization Pass2InlineCast
+Simplifying constant pointer cast (byte*) 1024
+Simplifying constant integer cast 3
+Simplifying constant integer cast 7
+Successful SSA optimization PassNCastSimplification
+Finalized unsigned number type (byte) 3
+Finalized unsigned number type (byte) 7
+Successful SSA optimization PassNFinalizeNumberTypeConversions
+Simple Condition (bool~) main::$0 [2] if((byte) main::i<(byte) 7) goto main::@2
+Successful SSA optimization Pass2ConditionalJumpSimplification
+Adding NOP phi() at start of @begin
+Adding NOP phi() at start of @1
+Adding NOP phi() at start of @2
+Adding NOP phi() at start of @end
+CALL GRAPH
+Calls in [] to main:2 
+
+Created 0 initial phi equivalence classes
+Coalesced down to 0 phi equivalence classes
+Culled Empty Block (label) @2
+Adding NOP phi() at start of @begin
+Adding NOP phi() at start of @1
+Adding NOP phi() at start of @end
+
+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()
+
+(void()) main()
+main: scope:[main]  from @1
+  [4] (byte) main::i ← (byte) 3
+  to:main::@1
+main::@1: scope:[main]  from main main::@2
+  [5] if((byte) main::i<(byte) 7) goto main::@2
+  to:main::@return
+main::@return: scope:[main]  from main::@1
+  [6] return 
+  to:@return
+main::@2: scope:[main]  from main::@1
+  [7] *((const byte*) SCREEN + (byte) main::i) ← (byte) main::i
+  [8] (byte) main::i ← ++ (byte) main::i
+  to:main::@1
+
+
+VARIABLE REGISTER WEIGHTS
+(void()) main()
+(byte) main::i loadstore 19.0
+
+Initial phi equivalence classes
+Added variable main::i to live range equivalence class [ main::i ]
+Complete equivalence classes
+[ main::i ]
+Allocated zp[1]:2 [ main::i ]
+
+INITIAL ASM
+Target platform is c64basic / MOS6502X
+  // File Comments
+// Test that volatile vars are turned into load/store
+  // Upstart
+.pc = $801 "Basic"
+:BasicUpstart(__bbegin)
+.pc = $80d "Program"
+  // Global Constants & labels
+  .label SCREEN = $400
+  // @begin
+__bbegin:
+  // [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 i = 2
+    // [4] (byte) main::i ← (byte) 3 -- vbuz1=vbuc1 
+    lda #3
+    sta.z i
+    jmp __b1
+    // main::@1
+  __b1:
+    // [5] if((byte) main::i<(byte) 7) goto main::@2 -- vbuz1_lt_vbuc1_then_la1 
+    lda.z i
+    cmp #7
+    bcc __b2
+    jmp __breturn
+    // main::@return
+  __breturn:
+    // [6] return 
+    rts
+    // main::@2
+  __b2:
+    // [7] *((const byte*) SCREEN + (byte) main::i) ← (byte) main::i -- pbuc1_derefidx_vbuz1=vbuz1 
+    ldy.z i
+    tya
+    sta SCREEN,y
+    // [8] (byte) main::i ← ++ (byte) main::i -- vbuz1=_inc_vbuz1 
+    inc.z i
+    jmp __b1
+}
+  // File Data
+
+REGISTER UPLIFT POTENTIAL REGISTERS
+Statement [4] (byte) main::i ← (byte) 3 [ main::i ] ( main:2 [ main::i ] ) always clobbers reg byte a 
+Statement [5] if((byte) main::i<(byte) 7) goto main::@2 [ main::i ] ( main:2 [ main::i ] ) always clobbers reg byte a 
+Statement [7] *((const byte*) SCREEN + (byte) main::i) ← (byte) main::i [ ] ( main:2 [ ] ) always clobbers reg byte a reg byte y 
+Potential registers zp[1]:2 [ main::i ] : zp[1]:2 , 
+
+REGISTER UPLIFT SCOPES
+Uplift Scope [main] 19: zp[1]:2 [ main::i ] 
+Uplift Scope [] 
+
+Uplifting [main] best 311 combination zp[1]:2 [ main::i ] 
+Uplifting [] best 311 combination 
+Attempting to uplift remaining variables inzp[1]:2 [ main::i ]
+Uplifting [main] best 311 combination zp[1]:2 [ main::i ] 
+
+ASSEMBLER BEFORE OPTIMIZATION
+  // File Comments
+// Test that volatile vars are turned into load/store
+  // Upstart
+.pc = $801 "Basic"
+:BasicUpstart(__bbegin)
+.pc = $80d "Program"
+  // Global Constants & labels
+  .label SCREEN = $400
+  // @begin
+__bbegin:
+  // [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 i = 2
+    // [4] (byte) main::i ← (byte) 3 -- vbuz1=vbuc1 
+    lda #3
+    sta.z i
+    jmp __b1
+    // main::@1
+  __b1:
+    // [5] if((byte) main::i<(byte) 7) goto main::@2 -- vbuz1_lt_vbuc1_then_la1 
+    lda.z i
+    cmp #7
+    bcc __b2
+    jmp __breturn
+    // main::@return
+  __breturn:
+    // [6] return 
+    rts
+    // main::@2
+  __b2:
+    // [7] *((const byte*) SCREEN + (byte) main::i) ← (byte) main::i -- pbuc1_derefidx_vbuz1=vbuz1 
+    ldy.z i
+    tya
+    sta SCREEN,y
+    // [8] (byte) main::i ← ++ (byte) main::i -- vbuz1=_inc_vbuz1 
+    inc.z i
+    jmp __b1
+}
+  // File Data
+
+ASSEMBLER OPTIMIZATIONS
+Removing instruction jmp __b1
+Removing instruction jmp __bend
+Removing instruction jmp __b1
+Removing instruction jmp __breturn
+Succesful ASM optimization Pass5NextJumpElimination
+Replacing label __bbegin with __b1
+Removing instruction __bbegin:
+Removing instruction __b1_from___bbegin:
+Removing instruction __bend_from___b1:
+Succesful ASM optimization Pass5RedundantLabelElimination
+Removing instruction __bend:
+Removing instruction __breturn:
+Succesful ASM optimization Pass5UnusedLabelElimination
+Updating BasicUpstart to call main directly
+Removing instruction jsr main
+Succesful ASM optimization Pass5SkipBegin
+Removing instruction __b1:
+Succesful ASM optimization Pass5UnusedLabelElimination
+
+FINAL SYMBOL TABLE
+(label) @1
+(label) @begin
+(label) @end
+(const byte*) SCREEN = (byte*) 1024
+(void()) main()
+(label) main::@1
+(label) main::@2
+(label) main::@return
+(byte) main::i loadstore zp[1]:2 19.0
+
+zp[1]:2 [ main::i ]
+
+
+FINAL ASSEMBLER
+Score: 266
+
+  // File Comments
+// Test that volatile vars are turned into load/store
+  // Upstart
+.pc = $801 "Basic"
+:BasicUpstart(main)
+.pc = $80d "Program"
+  // Global Constants & labels
+  .label SCREEN = $400
+  // @begin
+  // [1] phi from @begin to @1 [phi:@begin->@1]
+  // @1
+  // [2] call main 
+  // [3] phi from @1 to @end [phi:@1->@end]
+  // @end
+  // main
+main: {
+    .label i = 2
+    // i = 3
+    // [4] (byte) main::i ← (byte) 3 -- vbuz1=vbuc1 
+    lda #3
+    sta.z i
+    // main::@1
+  __b1:
+    // while(i<7)
+    // [5] if((byte) main::i<(byte) 7) goto main::@2 -- vbuz1_lt_vbuc1_then_la1 
+    lda.z i
+    cmp #7
+    bcc __b2
+    // main::@return
+    // }
+    // [6] return 
+    rts
+    // main::@2
+  __b2:
+    // SCREEN[i++] = i
+    // [7] *((const byte*) SCREEN + (byte) main::i) ← (byte) main::i -- pbuc1_derefidx_vbuz1=vbuz1 
+    ldy.z i
+    tya
+    sta SCREEN,y
+    // SCREEN[i++] = i;
+    // [8] (byte) main::i ← ++ (byte) main::i -- vbuz1=_inc_vbuz1 
+    inc.z i
+    jmp __b1
+}
+  // File Data
+

src/test/ref/volatile-1.sym

@@ -0,0 +1,11 @@
+(label) @1
+(label) @begin
+(label) @end
+(const byte*) SCREEN = (byte*) 1024
+(void()) main()
+(label) main::@1
+(label) main::@2
+(label) main::@return
+(byte) main::i loadstore zp[1]:2 19.0
+
+zp[1]:2 [ main::i ]