[Sema] Suppress warnings for C's zero initializer

Patch by S. Gilles!

Differential Revision: https://reviews.llvm.org/D28148

llvm-svn: 314499
diff --git a/clang/test/Sema/zero-initializer.c b/clang/test/Sema/zero-initializer.c
new file mode 100644
index 0000000..472eed9
--- /dev/null
+++ b/clang/test/Sema/zero-initializer.c
@@ -0,0 +1,38 @@
+// RUN: %clang_cc1 -std=c99 -Wmissing-field-initializers -Wmissing-braces -verify %s
+
+// Tests that using {0} in struct initialization or assignment is supported
+struct foo { int x; int y; };
+struct bar { struct foo a; struct foo b; };
+struct A { int a; };
+struct B { struct A a; };
+struct C { struct B b; };
+
+int main(void)
+{
+  struct foo f = { 0 }; // no-warning
+  struct foo g = { 9 }; // expected-warning {{missing field 'y' initializer}}
+  struct foo h = { 9, 9 }; // no-warning
+  struct bar i = { 0 }; // no-warning
+  struct bar j = { 0, 0 }; // expected-warning {{suggest braces around initialization of subobject}} expected-warning {{missing field 'b' initializer}}
+  struct bar k = { { 9, 9 }, { 9, 9 } }; // no-warning
+  struct bar l = { { 9, 9 }, { 0 } }; // no-warning
+  struct bar m = { { 0 }, { 0 } }; // no-warning
+  struct bar n = { { 0 }, { 9, 9 } }; // no-warning
+  struct bar o = { { 9 }, { 9, 9 } }; // expected-warning {{missing field 'y' initializer}}
+  struct C p = { 0 }; // no-warning
+  struct C q = { 9 }; // expected-warning {{suggest braces around initialization of subobject}} expected-warning {{suggest braces around initialization of subobject}}
+  f = (struct foo ) { 0 }; // no-warning
+  g = (struct foo ) { 9 }; // expected-warning {{missing field 'y' initializer}}
+  h = (struct foo ) { 9, 9 }; // no-warning
+  i = (struct bar) { 0 }; // no-warning
+  j = (struct bar) { 0, 0 }; // expected-warning {{suggest braces around initialization of subobject}} expected-warning {{missing field 'b' initializer}}
+  k = (struct bar) { { 9, 9 }, { 9, 9 } }; // no-warning
+  l = (struct bar) { { 9, 9 }, { 0 } }; // no-warning
+  m = (struct bar) { { 0 }, { 0 } }; // no-warning
+  n = (struct bar) { { 0 }, { 9, 9 } }; // no-warning
+  o = (struct bar) { { 9 }, { 9, 9 } }; // expected-warning {{missing field 'y' initializer}}
+  p = (struct C) { 0 }; // no-warning
+  q = (struct C) { 9 }; // expected-warning {{suggest braces around initialization of subobject}} expected-warning {{suggest braces around initialization of subobject}}
+
+  return 0;
+}