tests: cover 32-bit enum edge cases

Author: dbabokin

tests/lit-tests/enum-32bit-limits.ispc

@@ -0,0 +1,14 @@
+// RUN: %ispc %s -o %t.o --target=host
+
+// Regression test for allowing 32-bit enum values with the high bit set.
+
+enum Flags {
+    FLAG_HIGH_BIT = 0x80000000,
+    FLAG_ALL = 0xffffffff
+};
+
+export uniform int use_enum_values() {
+    uniform int a = (int)FLAG_HIGH_BIT;
+    uniform int b = (int)FLAG_ALL;
+    return a + b;
+}

tests/lit-tests/enum-32bit-overflow-error.ispc

@@ -0,0 +1,7 @@
+// RUN: not %{ispc} --nowrap --nostdlib --target=host %s -o - 2>&1 | FileCheck %s
+
+// CHECK: Error: Enumerator value must be representable with a 32-bit integer.
+
+enum TooBig {
+    TOO_BIG = 0x100000000
+};