1 files changed, 88 insertions, 0 deletions
diff --git a/clang/test/Sema/self-comparison.c b/clang/test/Sema/self-comparison.c
new file mode 100644
index 0000000..edb3a6a
--- /dev/null
+++ b/clang/test/Sema/self-comparison.c
@@ -0,0 +1,88 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+int foo(int x) {
+  return x == x; // expected-warning {{self-comparison always evaluates to true}}
+}
+
+int foo2(int x) {
+  return (x) != (((x))); // expected-warning {{self-comparison always evaluates to false}}
+}
+
+void foo3(short s, short t) { 
+  if (s == s) {} // expected-warning {{self-comparison always evaluates to true}}
+  if (s == t) {} // no-warning
+}
+
+void foo4(void* v, void* w) {
+  if (v == v) {} // expected-warning {{self-comparison always evaluates to true}}
+  if (v == w) {} // no-warning
+}
+
+int qux(int x) {
+   return x < x; // expected-warning {{self-comparison}}
+}
+
+int qux2(int x) {
+   return x > x; // expected-warning {{self-comparison}}
+}
+
+int bar(float x) {
+  return x == x; // no-warning
+}
+
+int bar2(float x) {
+  return x != x; // no-warning
+}
+
+#define IS_THE_ANSWER(x) (x == 42)
+
+int macro_comparison() {
+  return IS_THE_ANSWER(42);
+}
+
+// Don't complain in unevaluated contexts.
+int compare_sizeof(int x) {
+  return sizeof(x == x); // no-warning
+}
+
+int array_comparisons() {
+  int array1[2];
+  int array2[2];
+
+  //
+  // compare same array
+  //
+  return array1 == array1; // expected-warning{{self-comparison always evaluates to true}}
+  return array1 != array1; // expected-warning{{self-comparison always evaluates to false}}
+  return array1 < array1; // expected-warning{{self-comparison always evaluates to false}}
+  return array1 <= array1; // expected-warning{{self-comparison always evaluates to true}}
+  return array1 > array1; // expected-warning{{self-comparison always evaluates to false}}
+  return array1 >= array1; // expected-warning{{self-comparison always evaluates to true}}
+
+  //
+  // compare differrent arrays
+  //
+  return array1 == array2; // expected-warning{{array comparison always evaluates to false}}
+  return array1 != array2; // expected-warning{{array comparison always evaluates to true}}
+
+  //
+  // we don't know what these are going to be
+  //
+  return array1 < array2; // expected-warning{{array comparison always evaluates to a constant}}
+  return array1 <= array2; // expected-warning{{array comparison always evaluates to a constant}}
+  return array1 > array2; // expected-warning{{array comparison always evaluates to a constant}}
+  return array1 >= array2; // expected-warning{{array comparison always evaluates to a constant}}
+
+}
+
+// Don't issue a warning when either the left or right side of the comparison
+// results from a macro expansion.  <rdar://problem/8435950>
+#define R8435950_A i 
+#define R8435950_B i 
+
+int R8435950(int i) {
+  if (R8435950_A == R8435950_B) // no-warning
+   return 0;
+  return 1;
+}
+