test: Add besic enum conversions test.

test/vast/Conversion/enum-c.c

@@ -0,0 +1,53 @@
+// RUN: %vast-cc1 -vast-emit-mlir-after=vast-lower-value-categories %s -o - | %file-check %s
+
+enum E { A, B, C };
+
+void enum_resolve() {
+    // CHECK: [[E:%[0-9]+]] = ll.alloca : !hl.ptr<ui32>
+    // CHECK: [[V:%[0-9]+]] = hl.const #core.integer<1>
+    // CHECK: [[C:%[0-9]+]] = hl.implicit_cast [[V]] IntegralCast
+    // CHECK: ll.store [[E]], [[C]]
+    enum E e = B;
+}
+
+void enum_cast() {
+    // CHECK: [[E:%[0-9]+]] = ll.alloca : !hl.ptr<ui32>
+    // CHECK: [[V:%[0-9]+]] = hl.const #core.integer<2>
+    // CHECK: [[C:%[0-9]+]] = hl.cstyle_cast [[V]] IntegralCast
+    // CHECK: ll.store [[E]], [[C]]
+    enum E e = (enum E)2;
+}
+
+void enum_in_scope() {
+    // CHECK: [[E:%[0-9]+]] = ll.alloca : !hl.ptr<ui32>
+    enum E e;
+    {
+        // CHECK: [[V:%[0-9]+]] = hl.const #core.integer<0>
+        // CHECK: [[C:%[0-9]+]] = hl.implicit_cast [[V]] IntegralCast
+        // CHECK: ll.store [[E]], [[C]]
+        e = A;
+    }
+}
+
+typedef enum E e_t;
+
+void enum_typedef() {
+    // CHECK: [[E:%[0-9]+]] = ll.alloca : !hl.ptr<ui32>
+    // CHECK: [[V:%[0-9]+]] = hl.const #core.integer<0>
+    // CHECK: [[C:%[0-9]+]] = hl.implicit_cast [[V]] IntegralCast
+    // CHECK: ll.store [[E]], [[C]]
+    e_t e = A;
+}
+
+
+void enum_param(enum E e) {
+    // CHECK: [[E:%[0-9]+]] = ll.alloca : !hl.ptr<ui32>
+    // CHECK: ll.store [[E]], %arg0
+}
+
+enum E return_enum() {
+    // CHECK: [[V:%[0-9]+]] = hl.const #core.integer<1>
+    // CHECK: [[C:%[0-9]+]] = hl.implicit_cast [[V]] IntegralCast
+    // CHECK: ll.return [[C]]
+    return B;
+}