diff --git a/lib/templatesimplifier.cpp b/lib/templatesimplifier.cpp
index ec7e9b8a0..e936e33a7 100644
--- a/lib/templatesimplifier.cpp
+++ b/lib/templatesimplifier.cpp
@@ -845,12 +845,22 @@ static std::string ShiftInt(const char cop, const Token* left, const Token* righ
     if (cop == '&' || cop == '|' || cop == '^')
         return MathLib::calculate(left->str(), right->str(), cop);
 
-    const MathLib::bigint leftInt=MathLib::toLongNumber(left->str());
-    const MathLib::bigint rightInt=MathLib::toLongNumber(right->str());
+    const MathLib::bigint leftInt = MathLib::toLongNumber(left->str());
+    const MathLib::bigint rightInt = MathLib::toLongNumber(right->str());
+    const bool rightIntIsPositive = rightInt >= 0;
+    const bool leftIntIsPositive = leftInt >= 0;
+    const bool leftOperationIsNotLeftShift = left->previous()->str() != "<<";
+    const bool operandIsLeftShift = right->previous()->str() == "<<";
+
     if (cop == '<') {
-        if (left->previous()->str() != "<<" && rightInt > 0) // Ensure that its not a shift operator as used for streams
+        // Ensure that its not a shift operator as used for streams
+        if (leftOperationIsNotLeftShift && operandIsLeftShift && rightIntIsPositive) {
+            if (!leftIntIsPositive) { // In case the left integer is negative, e.g. -1000 << 16. Do not simplify.
+                return left->str() + " << " + right->str();
+            }
             return MathLib::toString(leftInt << rightInt);
-    } else if (rightInt > 0) {
+        }
+    } else if (rightIntIsPositive) {
         return MathLib::toString(leftInt >> rightInt);
     }
     return "";
diff --git a/test/testtokenize.cpp b/test/testtokenize.cpp
index 86d29cc79..7c3eae02c 100644
--- a/test/testtokenize.cpp
+++ b/test/testtokenize.cpp
@@ -66,6 +66,7 @@ private:
         TEST_CASE(tokenize29);  // #5506 (segmentation fault upon invalid code)
         TEST_CASE(tokenize30);  // #5356 (segmentation fault upon invalid code)
         TEST_CASE(tokenize31);  // #3503 (Wrong handling of member function taking function pointer as argument)
+        TEST_CASE(tokenize32);  // #5884 (fsanitize=undefined: left shift of negative value -10000 in lib/templatesimplifier.cpp:852:46)
 
         // don't freak out when the syntax is wrong
         TEST_CASE(wrong_syntax1);
@@ -891,6 +892,13 @@ private:
                                            "};"));
     }
 
+    // #5884 - Avoid left shift of negative integer value.
+    void tokenize32() {
+        // Do not simplify negative integer left shifts.
+        const char * code = "void f ( ) { int max_x ; max_x = -10000 << 16 ; }";
+        ASSERT_EQUALS(code, tokenizeAndStringify(code));
+    }
+
     void wrong_syntax1() {
         {
             const char code[] ="TR(kvmpio, PROTO(int rw), ARGS(rw), TP_(aa->rw;))";