diff --git a/src/main/fragment/cache/fragment-cache-mos6502x.asm b/src/main/fragment/cache/fragment-cache-mos6502x.asm
index 804346e37..03d14e64e 100644
--- a/src/main/fragment/cache/fragment-cache-mos6502x.asm
+++ b/src/main/fragment/cache/fragment-cache-mos6502x.asm
@@ -5241,6 +5241,102 @@ tax
 tya
 lsr
 tay
+//FRAGMENT vssz1=_stackidxstruct_4_vbuc1
+tsx
+lda STACK_BASE+{c1},x
+sta {z1}
+lda STACK_BASE+{c1}+1,x
+sta {z1}+1
+lda STACK_BASE+{c1}+2,x
+sta {z1}+2
+lda STACK_BASE+{c1}+3,x
+sta {z1}+3
+//FRAGMENT vbuz1=vbuz2_plus_1
+ldy {z2}
+iny
+sty {z1}
+//FRAGMENT _stackidxstruct_4_vbuc1=vssz1
+tsx
+lda {z1}
+sta STACK_BASE+{c1},x
+lda {z1}+1
+sta STACK_BASE+{c1}+1,x
+lda {z1}+2
+sta STACK_BASE+{c1}+2,x
+lda {z1}+3
+sta STACK_BASE+{c1}+3,x
+//FRAGMENT _stackpushpadding_3
+pha
+pha
+pha
+//FRAGMENT vssz1=_stackpullstruct_4_
+pla
+sta {z1}
+pla
+sta {z1}+1
+pla
+sta {z1}+2
+pla
+sta {z1}+3
+//FRAGMENT _stackpushstruct_4_=vssz1
+lda {z1}+3
+pha
+lda {z1}+2
+pha
+lda {z1}+1
+pha
+lda {z1}
+pha
+//FRAGMENT _stackpullpadding_4
+tsx
+txa
+axs #-4
+txs
+//FRAGMENT vbuaa=vbuz1_plus_1
+lda {z1}
+clc
+adc #1
+//FRAGMENT vbuxx=vbuz1_plus_1
+ldx {z1}
+inx
+//FRAGMENT vbuz1=vbuxx_plus_1
+inx
+stx {z1}
+//FRAGMENT vbuz1=vbuyy_plus_1
+iny
+sty {z1}
+//FRAGMENT vbuxx=vbuyy_plus_1
+tya
+tax
+inx
+//FRAGMENT vbuyy=vbuz1_plus_1
+ldy {z1}
+iny
+//FRAGMENT vbuyy=vbuxx_plus_1
+txa
+tay
+iny
+//FRAGMENT pbuz1=_stackidxptr_vbuc1
+tsx
+lda STACK_BASE+{c1},x
+sta {z1}
+lda STACK_BASE+{c1}+1,x
+sta {z1}+1
+//FRAGMENT _stackpushptr_=pbuc1
+lda #>{c1}
+pha
+lda #<{c1}
+pha
+//FRAGMENT _stackpullpadding_3
+tsx
+txa
+axs #-3
+txs
+//FRAGMENT vbuz1_lt_vbuxx_then_la1
+cpx {z1}
+beq !+
+bcs {la1}
+!:
 //FRAGMENT vbuz1=vbuz2_minus_1
 ldx {z2}
 dex
@@ -5550,10 +5646,6 @@ asl {z1}
 rol {z1}+1
 asl {z1}
 rol {z1}+1
-//FRAGMENT vbuz1=vbuz2_plus_1
-ldy {z2}
-iny
-sty {z1}
 //FRAGMENT vbuz1=vbuaa_plus_1
 clc
 adc #1
@@ -5563,9 +5655,6 @@ tay
 lda {c1},y
 ldy {z2}
 sta ({z1}),y
-//FRAGMENT vbuz1=vbuxx_plus_1
-inx
-stx {z1}
 //FRAGMENT vbuxx=pbuc1_derefidx_vbuyy
 ldx {c1},y
 //FRAGMENT vbuyy=pbuc1_derefidx_vbuxx
@@ -6524,11 +6613,6 @@ lda ({z1}),y
 
 cmp ({z2}),y
 beq {la1}
-//FRAGMENT vbuz1_lt_vbuxx_then_la1
-cpx {z1}
-beq !+
-bcs {la1}
-!:
 //FRAGMENT vbuyy_lt_vbuz1_then_la1
 cpy {z1}
 bcc {la1}
@@ -6545,12 +6629,6 @@ bcs {la1}
 sty $ff
 cpx $ff
 bcc {la1}
-//FRAGMENT vbuxx=vbuz1_plus_1
-ldx {z1}
-inx
-//FRAGMENT vbuyy=vbuz1_plus_1
-ldy {z1}
-iny
 //FRAGMENT vwuz1=vwuz1_bor_vbuxx
 txa
 ora {z1}
@@ -8651,27 +8729,12 @@ lda {z1}
 sta {c1}
 lda {z1}+1
 sta {c1}+1
-//FRAGMENT vbuaa=vbuz1_plus_1
-lda {z1}
-clc
-adc #1
-//FRAGMENT vbuz1=vbuyy_plus_1
-iny
-sty {z1}
 //FRAGMENT vbuaa=vbuxx_plus_1
 inx
 txa
 //FRAGMENT vbuaa=vbuyy_plus_1
 iny
 tya
-//FRAGMENT vbuxx=vbuyy_plus_1
-tya
-tax
-inx
-//FRAGMENT vbuyy=vbuxx_plus_1
-txa
-tay
-iny
 //FRAGMENT pssz1=pssc1_plus_vbuz2
 lda {z2}
 clc
@@ -16237,66 +16300,3 @@ sta {c1},x
 lda #{c2}
 ora {c1},y
 sta {c1},y
-//FRAGMENT vssz1=_stackidxstruct_4_vbuc1
-tsx
-lda STACK_BASE+{c1},x
-sta {z1}
-lda STACK_BASE+{c1}+1,x
-sta {z1}+1
-lda STACK_BASE+{c1}+2,x
-sta {z1}+2
-lda STACK_BASE+{c1}+3,x
-sta {z1}+3
-//FRAGMENT _stackidxstruct_4_vbuc1=vssz1
-tsx
-lda {z1}
-sta STACK_BASE+{c1},x
-lda {z1}+1
-sta STACK_BASE+{c1}+1,x
-lda {z1}+2
-sta STACK_BASE+{c1}+2,x
-lda {z1}+3
-sta STACK_BASE+{c1}+3,x
-//FRAGMENT _stackpushpadding_3
-pha
-pha
-pha
-//FRAGMENT vssz1=_stackpullstruct_4_
-pla
-sta {z1}
-pla
-sta {z1}+1
-pla
-sta {z1}+2
-pla
-sta {z1}+3
-//FRAGMENT _stackpushstruct_4_=vssz1
-lda {z1}+3
-pha
-lda {z1}+2
-pha
-lda {z1}+1
-pha
-lda {z1}
-pha
-//FRAGMENT _stackpullpadding_4
-tsx
-txa
-axs #-4
-txs
-//FRAGMENT pbuz1=_stackidxptr_vbuc1
-tsx
-lda STACK_BASE+{c1},x
-sta {z1}
-lda STACK_BASE+{c1}+1,x
-sta {z1}+1
-//FRAGMENT _stackpushptr_=pbuc1
-lda #>{c1}
-pha
-lda #<{c1}
-pha
-//FRAGMENT _stackpullpadding_3
-tsx
-txa
-axs #-3
-txs
diff --git a/src/main/java/dk/camelot64/kickc/fragment/AsmFragmentTemplate.java b/src/main/java/dk/camelot64/kickc/fragment/AsmFragmentTemplate.java
index 9600809cf..94f2aa4b8 100644
--- a/src/main/java/dk/camelot64/kickc/fragment/AsmFragmentTemplate.java
+++ b/src/main/java/dk/camelot64/kickc/fragment/AsmFragmentTemplate.java
@@ -41,7 +41,7 @@ public class AsmFragmentTemplate {
    private Double cycles;
 
    public AsmFragmentTemplate(String signature, String body, TargetCpu targetCpu) {
-      this.signature = signature;
+      this.signature = signature.intern();
       this.body = body;
       this.targetCpu = targetCpu;
    }
diff --git a/src/main/java/dk/camelot64/kickc/fragment/AsmFragmentTemplateCache.java b/src/main/java/dk/camelot64/kickc/fragment/AsmFragmentTemplateCache.java
index ef52c1f68..2b6b1924e 100644
--- a/src/main/java/dk/camelot64/kickc/fragment/AsmFragmentTemplateCache.java
+++ b/src/main/java/dk/camelot64/kickc/fragment/AsmFragmentTemplateCache.java
@@ -73,7 +73,7 @@ public class AsmFragmentTemplateCache {
     * @param asmFragmentTemplate The ASM fragment template.  NO_SYNTHESIS if synthesis was unsuccessful.
     */
    public void put(String signature, AsmFragmentTemplate asmFragmentTemplate) {
-      this.cache.put(signature, asmFragmentTemplate);
+      this.cache.put(signature.intern(), asmFragmentTemplate);
       this.modified = true;
    }
 
@@ -186,11 +186,11 @@ public class AsmFragmentTemplateCache {
    private static void addFragment(LinkedHashMap<String, AsmFragmentTemplate> cache, String signature, StringBuilder body, TargetCpu targetCpu) {
       final String bodyString = body.toString();
       if(bodyString.startsWith(NO_SYNTHESIS.getBody())) {
-         cache.put(signature, NO_SYNTHESIS);
+         cache.put(signature.intern(), NO_SYNTHESIS);
       } else {
          CharStream fragmentCharStream = CharStreams.fromString(bodyString);
          AsmFragmentTemplate template = new AsmFragmentTemplate(signature, AsmFragmentTemplateSynthesizer.fixNewlines(fragmentCharStream.toString()), targetCpu);
-         cache.put(signature, template);
+         cache.put(signature.intern(), template);
       }
    }
 
diff --git a/src/main/java/dk/camelot64/kickc/fragment/synthesis/AsmFragmentSynthesis.java b/src/main/java/dk/camelot64/kickc/fragment/synthesis/AsmFragmentSynthesis.java
index 5e2cb22a0..f958a274a 100644
--- a/src/main/java/dk/camelot64/kickc/fragment/synthesis/AsmFragmentSynthesis.java
+++ b/src/main/java/dk/camelot64/kickc/fragment/synthesis/AsmFragmentSynthesis.java
@@ -24,12 +24,12 @@ public class AsmFragmentSynthesis {
     /**
      * Options for synthesizing the template from sub-fragments using a specific synthesis rule. Forward edges in the synthesis graph.
      */
-    private final Set<AsmFragmentSynthesisOption> synthesisOptions;
+    private final List<AsmFragmentSynthesisOption> synthesisOptions;
 
     /**
      * Options for synthesizing the other templates from this template using a specific synthesis rule. Backward edges in the synthesis graph.
      */
-    private final Set<AsmFragmentSynthesisOption> parentOptions;
+    private final List<AsmFragmentSynthesisOption> parentOptions;
 
     /**
      * The templates loaded from a file. Empty if no file exists for the signature.
@@ -42,10 +42,10 @@ public class AsmFragmentSynthesis {
      * @param signature The signature of the fragment template to load/synthesize
      */
     AsmFragmentSynthesis(String signature) {
-        this.signature = signature;
+        this.signature = signature.intern();
         this.bestTemplates = new LinkedHashMap<>();
-        this.synthesisOptions = new LinkedHashSet<>();
-        this.parentOptions = new LinkedHashSet<>();
+        this.synthesisOptions = new ArrayList<>();
+        this.parentOptions = new ArrayList<>();
         this.fileTemplates = new ArrayList<>();
     }
 
@@ -149,7 +149,7 @@ public class AsmFragmentSynthesis {
      *
      * @return The parent options.
      */
-    Set<AsmFragmentSynthesisOption> getParentOptions() {
+    List<AsmFragmentSynthesisOption> getParentOptions() {
         return parentOptions;
     }
 
diff --git a/src/main/java/dk/camelot64/kickc/fragment/synthesis/AsmFragmentSynthesisOption.java b/src/main/java/dk/camelot64/kickc/fragment/synthesis/AsmFragmentSynthesisOption.java
index b1c849eb6..6fb623aa4 100644
--- a/src/main/java/dk/camelot64/kickc/fragment/synthesis/AsmFragmentSynthesisOption.java
+++ b/src/main/java/dk/camelot64/kickc/fragment/synthesis/AsmFragmentSynthesisOption.java
@@ -2,6 +2,7 @@ package dk.camelot64.kickc.fragment.synthesis;
 
 import java.util.List;
 import java.util.Objects;
+import java.util.stream.Collectors;
 
 /**
  * An option for synthesizing a fragment template from a sub-template using a specific synthesis rule. An edge in the synthesis graph.
@@ -30,9 +31,9 @@ public class AsmFragmentSynthesisOption {
      * @param rule      The synthesis rule capable of synthesizing this template from the sub-fragment.
      */
     AsmFragmentSynthesisOption(String signature, AsmFragmentTemplateSynthesisRule rule) {
-        this.signature = signature;
+        this.signature = signature.intern();
         this.rule = rule;
-        this.subSignatures = rule.getSubSignatures(signature);
+        this.subSignatures = rule.getSubSignatures(signature).stream().map(String::intern).collect(Collectors.toList());
     }
 
     public String getSignature() {
diff --git a/src/test/java/dk/camelot64/kickc/test/TestFragments.java b/src/test/java/dk/camelot64/kickc/test/TestFragments.java
index 373e3c6c6..ea0083897 100644
--- a/src/test/java/dk/camelot64/kickc/test/TestFragments.java
+++ b/src/test/java/dk/camelot64/kickc/test/TestFragments.java
@@ -36,7 +36,7 @@ public class TestFragments {
 
    @Test
    public void testSynthesis() throws IOException {
-      testFragmentExists("pbuz1=pbuz2_plus_pwuc1_derefidx_vbuxx");
+      testFragmentExists("vbuz1=pbuz2_derefidx_(pbuz3_derefidx_vbuz4)_plus_pbuz5_derefidx_(pbuz6_derefidx_vbuz4)");
    }
 
    @Test