Fix #10227: FP: pointer arithmetic out of bounds in unreachable expression (danmar#7057)

Author: ludviggunne

lib/checkbufferoverrun.cpp

@@ -500,7 +500,7 @@ void CheckBufferOverrun::pointerArithmetic()
                 const std::vector<const Token *> indexTokens{indexToken};
                 const std::vector<ValueFlow::Value>& indexValues =
                     getOverrunIndexValues(tok, arrayToken, dimensions, indexTokens, path);
-                if (!indexValues.empty())
+                if (!indexValues.empty() && !isUnreachableOperand(tok))
                     pointerArithmeticError(tok, indexToken, &indexValues.front());
             }
 

test/testbufferoverrun.cpp

@@ -248,6 +248,7 @@ class TestBufferOverrun : public TestFixture {
         TEST_CASE(pointer_out_of_bounds_2);
         TEST_CASE(pointer_out_of_bounds_3);
         TEST_CASE(pointer_out_of_bounds_4);
+        TEST_CASE(pointer_out_of_bounds_5); // #10227
         TEST_CASE(pointer_out_of_bounds_sub);
 
         TEST_CASE(strcat1);
@@ -3863,6 +3864,12 @@ class TestBufferOverrun : public TestFixture {
         ASSERT_EQUALS("", errout_str());
     }
 
+    void pointer_out_of_bounds_5() { // #10227
+        check("int foo(char str[6]) {\n"
+              "    return !((0 && *(\"STRING\" + 14) == 0) || memcmp(str, \"STRING\", 6) == 0);\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
+    }
 
     void pointer_out_of_bounds_sub() {
         // extracttests.start: void dostuff(char *);