Fix #12235 performance regression (hang) in 2.13dev (#5715)

Co-authored-by: chrchr-github <chrchr@github>

Author: chrchr-github

lib/astutils.cpp

@@ -2767,8 +2767,10 @@ static bool isExpressionChangedAt(const F& getExprTok,
 {
     if (depth < 0)
         return true;
+    if (tok->isLiteral() || tok->isKeyword() || tok->isStandardType() || Token::Match(tok, ",|;|:"))
+        return false;
     if (tok->exprId() != exprid) {
-        if (globalvar && !tok->isKeyword() && Token::Match(tok, "%name% (") && !(tok->function() && tok->function()->isAttributePure()))
+        if (globalvar && Token::Match(tok, "%name% (") && !(tok->function() && tok->function()->isAttributePure()))
             // TODO: Is global variable really changed by function call?
             return true;
         int i = 1;

test/cli/test-performance.py

@@ -146,4 +146,42 @@ def test_slow_exprid(tmpdir):
     cppcheck([filename], env=my_env)
 
 
-
+@pytest.mark.timeout(10)
+def test_slow_initlist_varchanged(tmpdir):
+    # #12235
+    filename = os.path.join(tmpdir, 'hang.cpp')
+    with open(filename, 'wt') as f:
+        f.write(r"""
+                struct T {
+                    int* q;
+                    int nx, ny;
+                };
+                struct S {
+                    void f();
+                    int n;
+                    T* p;
+                };
+                #define ROW 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ,
+                #define ROW4 ROW ROW ROW ROW
+                #define ROW16 ROW4 ROW4 ROW4 ROW4
+                #define ROW64 ROW16 ROW16 ROW16 ROW16
+                #define ROW256 ROW64 ROW64 ROW64 ROW64
+                #define ROW1K ROW256 ROW256 ROW256 ROW256
+                #define ROW4K ROW1K ROW1K ROW1K ROW1K
+                const int A[] = {
+                    ROW4K
+                };
+                void S::f() {
+                    for (int i = 0; i < n; ++i) {
+                        T& t = p[i];
+                        for (int y = 0; y < t.ny; y += 4) {
+                            int* row0 = t.q + y * t.nx;
+                            for (int x = 0; x < t.nx; x += 4) {
+                                int s[16] = {};
+                                memcpy(row0, &s[0], 4);
+                                row0 += 4;
+                            }
+                        }
+                    }
+                }""")
+    cppcheck([filename]) # should not take more than ~1 second

test/testastutils.cpp

@@ -243,6 +243,8 @@ class TestAstUtils : public TestFixture {
                                         "void f(int x) { g(&x); }\n",
                                         "{",
                                         "}"));
+
+        ASSERT_EQUALS(false, isVariableChanged("const int A[] = { 1, 2, 3 };", "[", "]"));
     }
 
 #define isVariableChangedByFunctionCall(code, pattern, inconclusive) isVariableChangedByFunctionCall_(code, pattern, inconclusive, __FILE__, __LINE__)