[clang][Interp] Fix zero-init of float and pointer arrays

Our Zero opcode only exists for integer types. Use
visitZeroInitializer() here as well so it works for floats and pointers.

Differential Revision: https://reviews.llvm.org/D149059

Author: tbaederr

clang/lib/AST/Interp/ByteCodeExprGen.cpp

@@ -1291,7 +1291,7 @@ bool ByteCodeExprGen<Emitter>::visitArrayInitializer(const Expr *Initializer) {
       //   since we memset our Block*s to 0 and so we have the desired value
       //   without this.
       for (size_t I = 0; I != NumElems; ++I) {
-        if (!this->emitZero(*ElemT, Initializer))
+        if (!this->visitZeroInitializer(CAT->getElementType(), Initializer))
           return false;
         if (!this->emitInitElem(*ElemT, I, Initializer))
           return false;

clang/test/AST/Interp/arrays.cpp

@@ -334,3 +334,19 @@ namespace IncDec {
                                    // ref-error {{not an integral constant expression}} \
                                   // ref-note {{in call to}}
 };
+
+namespace ZeroInit {
+  struct A {
+    int *p[2];
+  };
+  constexpr A a = {};
+  static_assert(a.p[0] == nullptr, "");
+  static_assert(a.p[1] == nullptr, "");
+
+  struct B {
+    double f[2];
+  };
+  constexpr B b = {};
+  static_assert(b.f[0] == 0.0, "");
+  static_assert(b.f[1] == 0.0, "");
+}