Fix union sizes and member offsets

3 files changed, 14 insertions, 2 deletions

diff --git a/decl.c b/decl.c
index 31eb0b9..235c975 100644
--- a/decl.c
+++ b/decl.c
@@ -660,8 +660,14 @@ structdecl(struct scope *s, struct type *t)
 			if (align < m->type->align)
 				align = m->type->align;
 			t->size = ALIGNUP(t->size, align);
-			m->offset = t->size;
-			t->size += m->type->size;
+			if (t->kind == TYPESTRUCT) {
+				m->offset = t->size;
+				t->size += m->type->size;
+			} else {
+				m->offset = 0;
+				if (t->size < m->type->size)
+					t->size = m->type->size;
+			}
 			if (t->align < align)
 				t->align = align;
 		}
diff --git a/tests/union.c b/tests/union.c
new file mode 100644
index 0000000..9b4e5f9
--- /dev/null
+++ b/tests/union.c
@@ -0,0 +1,4 @@
+union {
+	int x;
+	double y;
+} a = {.x = 5}, b = {.y = 7.5};
diff --git a/tests/union.qbe b/tests/union.qbe
new file mode 100644
index 0000000..adbda57
--- /dev/null
+++ b/tests/union.qbe
@@ -0,0 +1,2 @@
+export data $a = align 8 { w 5, z 4 }
+export data $b = align 8 { d d_0x1.ep+2, }