[clang][Interp][NFC] Add more _Complex tests

clang/test/AST/Interp/complex.cpp

@@ -313,3 +313,53 @@ namespace Cmp {
   static_assert((0.0 + 0.0j) > (0.0 + 0.0j)); // both-error {{invalid operands to binary expression}}
   static_assert((0.0 + 0.0j) ^ (0.0 + 0.0j)); // both-error {{invalid operands to binary expression}}
 }
+
+/// From test/SemaCXX/constant-expression-cxx11.cpp
+///
+/// Some of the diagnostics we emit are different than the one of the
+/// current interpreter.
+///
+/// FIXME: For the '&test3 + 1' test, we are _not_ creating an explicit pointer variable
+/// anywhere and so the &test3+1 is the same as __imag(test3) for us.
+namespace ComplexConstexpr {
+  constexpr _Complex float test1 = {};
+  constexpr _Complex float test2 = {1};
+  constexpr _Complex double test3 = {1,2};
+  constexpr _Complex int test4 = {4};
+  constexpr _Complex int test5 = 4;
+  constexpr _Complex int test6 = {5,6};
+  typedef _Complex float fcomplex;
+  constexpr fcomplex test7 = fcomplex();
+
+  constexpr const double &t2r = __real test3;
+  constexpr const double &t2i = __imag test3;
+  static_assert(&t2r + 1 == &t2i, "");
+  static_assert(t2r == 1.0, "");
+  static_assert(t2i == 2.0, "");
+  constexpr const double *t2p = &t2r;
+  static_assert(t2p[-1] == 0.0, ""); // both-error {{constant expr}} \
+                                     // both-note {{cannot refer to element -1 of array of 2 elements}}
+  static_assert(t2p[0] == 1.0, "");
+  static_assert(t2p[1] == 2.0, "");
+  static_assert(t2p[2] == 0.0, ""); // both-error {{constant expr}} \
+                                    // both-note {{one-past-the-end pointer}}
+  static_assert(t2p[3] == 0.0, ""); // both-error {{constant expr}} \
+                                    // both-note {{cannot refer to element 3 of array of 2 elements}}
+  constexpr _Complex float *p = 0;
+  constexpr float pr = __real *p; // both-error {{constant expr}} \
+                                  // ref-note {{cannot access real component of null}} \
+                                  // expected-note {{read of dereferenced null pointer}}
+  constexpr float pi = __imag *p; // both-error {{constant expr}} \
+                                  // ref-note {{cannot access imaginary component of null}} \
+                                  // expected-note {{cannot perform pointer arithmetic on null pointer}}
+  constexpr const _Complex double *q = &test3 + 1;
+  constexpr double qr = __real *q; // ref-error {{constant expr}} \
+                                   // ref-note {{cannot access real component of pointer past the end}}
+  constexpr double qi = __imag *q; // both-error {{constant expr}} \
+                                   // ref-note {{cannot access imaginary component of pointer past the end}} \
+                                   // expected-note {{read of dereferenced one-past-the-end pointer}}
+
+  static_assert(__real test6 == 5, "");
+  static_assert(__imag test6 == 6, "");
+  static_assert(&__imag test6 == &__real test6 + 1, "");
+}