Unnamed bit-fields don't contribute to size or alignment of unions, or size of structs

3 files changed, 21 insertions, 7 deletions

diff --git a/decl.c b/decl.c
index 35ba57a..b771a04 100644
--- a/decl.c
+++ b/decl.c
@@ -714,17 +714,15 @@ addmember(struct structbuilder *b, struct qualtype mt, char *name, int align, ui
 			}
 			t->size += (width - b->bits + 7) / 8;
 			b->bits = (b->bits - width) % 8;
-		} else {
-			if (m) {
-				m->offset = 0;
-				m->bits.before = 0;
-				m->bits.after = mt.type->size * 8 - width;
-			}
+		} else if (m) {
+			m->offset = 0;
+			m->bits.before = 0;
+			m->bits.after = mt.type->size * 8 - width;
 			if (t->size < mt.type->size)
 				t->size = mt.type->size;
 		}
 	}
-	if (t->align < align)
+	if (m && t->align < align)
 		t->align = align;
 }
 
diff --git a/test/bitfield-unnamed-size-align.c b/test/bitfield-unnamed-size-align.c
new file mode 100644
index 0000000..505467b
--- /dev/null
+++ b/test/bitfield-unnamed-size-align.c
@@ -0,0 +1,12 @@
+struct s {
+	int : 8;
+	char c;
+};
+union u {
+	int : 8;
+	char c;
+};
+int s1 = sizeof(struct s);
+int s2 = _Alignof(struct s);
+int u1 = sizeof(union u);
+int u2 = _Alignof(union u);
diff --git a/test/bitfield-unnamed-size-align.qbe b/test/bitfield-unnamed-size-align.qbe
new file mode 100644
index 0000000..67dfecc
--- /dev/null
+++ b/test/bitfield-unnamed-size-align.qbe
@@ -0,0 +1,4 @@
+export data $s1 = align 4 { w 2, }
+export data $s2 = align 4 { w 1, }
+export data $u1 = align 4 { w 1, }
+export data $u2 = align 4 { w 1, }