diff --git a/src/compiler/compile/render_dom/Renderer.ts b/src/compiler/compile/render_dom/Renderer.ts
index 8f0297a731..06d95fb1e6 100644
--- a/src/compiler/compile/render_dom/Renderer.ts
+++ b/src/compiler/compile/render_dom/Renderer.ts
@@ -26,7 +26,6 @@ export default class Renderer {
 
 	context: ContextMember[] = [];
 	context_lookup: Map<string, ContextMember> = new Map();
-	context_overflow: boolean;
 	blocks: Array<Block | Node | Node[]> = [];
 	readonly: Set<string> = new Set();
 	meta_bindings: Array<Node | Node[]> = []; // initial values for e.g. window.innerWidth, if there's a <svelte:window> meta tag
@@ -97,8 +96,6 @@ export default class Renderer {
 
 		this.fragment.render(this.block, null, x`#nodes` as Identifier);
 
-		this.context_overflow = this.context.length > 31;
-
 		this.context.forEach(member => {
 			const { variable } = member;
 			if (variable) {
@@ -240,15 +237,11 @@ export default class Renderer {
 					return x`${dirty} & /*${names.join(', ')}*/ 0` as BinaryExpression;
 				}
 
-				if (renderer.context_overflow) {
-					return bitmask
-						.map((b, i) => ({ b, i }))
-						.filter(({ b }) => b)
-						.map(({ b, i }) => x`${dirty}[${i}] & /*${b.names.join(', ')}*/ ${b.n}`)
-						.reduce((lhs, rhs) => x`${lhs} | ${rhs}`);
-				}
-
-				return x`${dirty}[0] & /*${names.join(', ')}*/ ${bitmask[0].n}` as BinaryExpression;
+				return bitmask
+					.map((b, i) => ({ b, i }))
+					.filter(({ b }) => b)
+					.map(({ b, i }) => x`${dirty}[${i}] & /*${b.names.join(', ')}*/ ${b.n}`)
+					.reduce((lhs, rhs) => x`${lhs} | ${rhs}`);
 			}
 		} as any;
 	}
diff --git a/src/compiler/compile/render_dom/index.ts b/src/compiler/compile/render_dom/index.ts
index 6edb946c29..d97c3bc730 100644
--- a/src/compiler/compile/render_dom/index.ts
+++ b/src/compiler/compile/render_dom/index.ts
@@ -429,7 +429,7 @@ export default function dom(
 	}` as ObjectExpression;
 
 	let dirty;
-	if (renderer.context_overflow) {
+	if (renderer.context.length > 31) {
 		dirty = x`[]`;
 		for (let i = 0; i < renderer.context.length; i += 31) {
 			dirty.elements.push(x`-1`);