diff --git a/icu4c/source/common/rbbirb.cpp b/icu4c/source/common/rbbirb.cpp
index 3becda3127..a0f92da619 100644
--- a/icu4c/source/common/rbbirb.cpp
+++ b/icu4c/source/common/rbbirb.cpp
@@ -359,10 +359,7 @@ void RBBIRuleBuilder::optimizeTables() {
 
     leftClass = 3;
     rightClass = 4;
-    printf("Optimizing tables ...\n");
     while (fForwardTables->findDuplCharClassFrom(leftClass, rightClass)) {
-        printf("Merging duplicate columns (%d, %d)\n", leftClass, rightClass);
-        
         fSetBuilder->mergeCategories(leftClass, rightClass);
         fForwardTables->removeColumn(rightClass);
         fReverseTables->removeColumn(rightClass);
diff --git a/icu4c/source/common/rbbisetb.cpp b/icu4c/source/common/rbbisetb.cpp
index 67bb460aca..108d127d45 100644
--- a/icu4c/source/common/rbbisetb.cpp
+++ b/icu4c/source/common/rbbisetb.cpp
@@ -274,9 +274,11 @@ void RBBISetBuilder::mergeCategories(int32_t left, int32_t right) {
     U_ASSERT(left >= 1);
     U_ASSERT(right > left);
     for (RangeDescriptor *rd = fRangeList; rd != nullptr; rd = rd->fNext) {
-        if (rd->fNum == right) {
-            rd->fNum = left;
-        } else if (rd->fNum > right) {
+        int32_t rangeNum = rd->fNum & ~DICT_BIT;
+        int32_t rangeDict = rd->fNum & DICT_BIT;
+        if (rangeNum == right) {
+            rd->fNum = left | rangeDict;
+        } else if (rangeNum > right) {
             rd->fNum--;
         }
     }
@@ -465,7 +467,7 @@ void RBBISetBuilder::printRangeGroups() {
             lastPrintedGroupNum = groupNum;
             RBBIDebugPrintf("%2i  ", groupNum);
 
-            if (rlRange->fNum & 0x4000) { RBBIDebugPrintf(" <DICT> ");}
+            if (rlRange->fNum & DICT_BIT) { RBBIDebugPrintf(" <DICT> ");}
 
             for (i=0; i<rlRange->fIncludesSets->size(); i++) {
                 RBBINode       *usetNode    = (RBBINode *)rlRange->fIncludesSets->elementAt(i);
@@ -658,20 +660,20 @@ void RangeDescriptor::split(UChar32 where, UErrorCode &status) {
 void RangeDescriptor::setDictionaryFlag() {
     int i;
 
-    for (i=0; i<this->fIncludesSets->size(); i++) {
-        RBBINode       *usetNode    = (RBBINode *)fIncludesSets->elementAt(i);
-        UnicodeString   setName;
-        RBBINode       *setRef = usetNode->fParent;
-        if (setRef != NULL) {
+    static const char16_t *dictionary = u"dictionary";
+    for (i=0; i<fIncludesSets->size(); i++) {
+        RBBINode *usetNode  = (RBBINode *)fIncludesSets->elementAt(i);
+        RBBINode *setRef = usetNode->fParent;
+        if (setRef != nullptr) {
             RBBINode *varRef = setRef->fParent;
-            if (varRef != NULL  &&  varRef->fType == RBBINode::varRef) {
-                setName = varRef->fText;
+            if (varRef && varRef->fType == RBBINode::varRef) {
+                const UnicodeString *setName = &varRef->fText;
+                if (setName->compare(dictionary, -1) == 0) {
+                    fNum |= RBBISetBuilder::DICT_BIT;
+                    break;
+                }
             }
         }
-        if (setName.compare(UNICODE_STRING("dictionary", 10)) == 0) {   // TODO:  no string literals.
-            this->fNum |= 0x4000;
-            break;
-        }
     }
 }
 
diff --git a/icu4c/source/common/rbbisetb.h b/icu4c/source/common/rbbisetb.h
index 3f0ec1a8a0..a7a91b3b37 100644
--- a/icu4c/source/common/rbbisetb.h
+++ b/icu4c/source/common/rbbisetb.h
@@ -99,6 +99,8 @@ public:
      */
     void     mergeCategories(int32_t left, int32_t right);
 
+    static constexpr int32_t DICT_BIT = 0x4000;
+
 #ifdef RBBI_DEBUG
     void     printSets();
     void     printRanges();
diff --git a/icu4c/source/test/intltest/rbbitst.cpp b/icu4c/source/test/intltest/rbbitst.cpp
index c6e0f457fb..b28723f456 100644
--- a/icu4c/source/test/intltest/rbbitst.cpp
+++ b/icu4c/source/test/intltest/rbbitst.cpp
@@ -4471,7 +4471,10 @@ void RBBITest::TestTableRedundancies() {
                 "($s1 | $s2 | $s3)*; \n" };
     RuleBasedBreakIterator *lbi = 
         (RuleBasedBreakIterator *)BreakIterator::createLineInstance(Locale::getEnglish(), status);
+    //lbi->dumpTables();
     rules = lbi->getRules();
+    delete lbi;
+
     UParseError pe {};
     RuleBasedBreakIterator *bi =
     //         (RuleBasedBreakIterator *)BreakIterator::createLineInstance(Locale::getEnglish(), status);