diff --git a/lib/checkother.cpp b/lib/checkother.cpp
index 758940cd7..3bdc4087d 100644
--- a/lib/checkother.cpp
+++ b/lib/checkother.cpp
@@ -2249,26 +2249,28 @@ void CheckOther::checkZeroDivision()
                 if (tok->variable() || tok->function())
                     continue;
             }
-            zerodivError(tok);
+            zerodivError(tok,false);
         } else if (Token::Match(tok, "[/%]") && tok->astOperand2() && !tok->astOperand2()->values.empty()) {
             // Value flow..
             const ValueFlow::Value *value = tok->astOperand2()->getValue(0LL);
             if (value) {
+                if (!_settings->inconclusive && value->inconclusive)
+                    continue;
                 if (value->condition == nullptr)
-                    zerodivError(tok);
+                    zerodivError(tok, value->inconclusive);
                 else if (_settings->isEnabled("warning"))
-                    zerodivcondError(value->condition,tok);
+                    zerodivcondError(value->condition,tok,value->inconclusive);
             }
         }
     }
 }
 
-void CheckOther::zerodivError(const Token *tok)
+void CheckOther::zerodivError(const Token *tok, bool inconclusive)
 {
-    reportError(tok, Severity::error, "zerodiv", "Division by zero.");
+    reportError(tok, Severity::error, "zerodiv", "Division by zero.", inconclusive);
 }
 
-void CheckOther::zerodivcondError(const Token *tokcond, const Token *tokdiv)
+void CheckOther::zerodivcondError(const Token *tokcond, const Token *tokdiv, bool inconclusive)
 {
     std::list<const Token *> callstack;
     while (Token::Match(tokcond, "(|%oror%|&&"))
@@ -2291,7 +2293,7 @@ void CheckOther::zerodivcondError(const Token *tokcond, const Token *tokdiv)
             condition = tokcond->str() + "!=0";
     }
     const std::string linenr(MathLib::toString(tokdiv ? tokdiv->linenr() : 0));
-    reportError(callstack, Severity::warning, "zerodivcond", "Either the condition '"+condition+"' is useless or there is division by zero at line " + linenr + ".");
+    reportError(callstack, Severity::warning, "zerodivcond", "Either the condition '"+condition+"' is useless or there is division by zero at line " + linenr + ".", inconclusive);
 }
 //---------------------------------------------------------------------------
 //---------------------------------------------------------------------------
diff --git a/lib/checkother.h b/lib/checkother.h
index 1580243f1..8b184d413 100644
--- a/lib/checkother.h
+++ b/lib/checkother.h
@@ -290,8 +290,8 @@ private:
     void charBitOpError(const Token *tok);
     void variableScopeError(const Token *tok, const std::string &varname);
     void strPlusCharError(const Token *tok);
-    void zerodivError(const Token *tok);
-    void zerodivcondError(const Token *tokcond, const Token *tokdiv);
+    void zerodivError(const Token *tok, bool inconclusive);
+    void zerodivcondError(const Token *tokcond, const Token *tokdiv, bool inconclusive);
     void nanInArithmeticExpressionError(const Token *tok);
     void mathfunctionCallError(const Token *tok, const unsigned int numParam = 1);
     void redundantAssignmentError(const Token *tok1, const Token* tok2, const std::string& var, bool inconclusive);
@@ -340,8 +340,8 @@ private:
         c.invalidFunctionArgError(0, "func_name", 1, "1-4");
         c.invalidFunctionArgBoolError(0, "func_name", 1);
         c.udivError(0, false);
-        c.zerodivError(0);
-        c.zerodivcondError(0,0);
+        c.zerodivError(0, false);
+        c.zerodivcondError(0,0,false);
         c.mathfunctionCallError(0);
         c.misusedScopeObjectError(NULL, "varname");
         c.doubleFreeError(0, "varname");
diff --git a/test/testother.cpp b/test/testother.cpp
index a2148591d..5906cae9a 100644
--- a/test/testother.cpp
+++ b/test/testother.cpp
@@ -45,6 +45,7 @@ private:
         TEST_CASE(zeroDiv5);
         TEST_CASE(zeroDiv6);
         TEST_CASE(zeroDiv7);  // #4930
+        TEST_CASE(zeroDiv8);
 
         TEST_CASE(zeroDivCond); // division by zero / useless condition
 
@@ -463,6 +464,16 @@ private:
                       "[test.cpp:3]: (error) Division by zero.\n", errout.str());
     }
 
+    void zeroDiv8() {
+        // #5584 - FP when function is unknown
+        check("void f() {\n"
+              "  int a = 0;\n"
+              "  do_something(a);\n"
+              "  return 4 / a;\n"
+              "}");
+        ASSERT_EQUALS("[test.cpp:4]: (error, inconclusive) Division by zero.\n", errout.str());
+    }
+
     void zeroDivCond() {
         check("void f(unsigned int x) {\n"
               "  int y = 17 / x;\n"