diff --git a/Common/Hashmaps.h b/Common/Hashmaps.h
index 2a7f5994cc..f9781166bb 100644
--- a/Common/Hashmaps.h
+++ b/Common/Hashmaps.h
@@ -29,7 +29,7 @@ enum class BucketState {
 // we always use very small values, so it's probably better to have them in the same
 // cache-line as the corresponding key.
 // Enforces that value are pointers to make sure that combined storage makes sense.
-template <class Key, class Value>
+template <class Key, class Value, Value NullValue>
 class DenseHashMap {
 public:
 	DenseHashMap(int initialCapacity) : capacity_(initialCapacity) {
@@ -46,12 +46,12 @@ public:
 			if (map[p].state == BucketState::TAKEN && KeyEquals(key, map[p].key))
 				return map[p].value;
 			else if (map[p].state == BucketState::FREE)
-				return nullptr;
+				return NullValue;
 			p = (p + 1) & mask;  // If the state is REMOVED, we just keep on walking. 
 			if (p == pos)
 				Crash();
 		}
-		return nullptr;
+		return NullValue;
 	}
 
 	// Returns false if we already had the key! Which is a bit different.
@@ -170,7 +170,7 @@ private:
 
 // Like the above, uses linear probing for cache-friendliness.
 // Does not perform hashing at all so expects well-distributed keys.
-template <class Value>
+template <class Value, Value NullValue>
 class PrehashMap {
 public:
 	PrehashMap(int initialCapacity) : capacity_(initialCapacity) {
@@ -187,12 +187,12 @@ public:
 			if (map[p].state == BucketState::TAKEN && hash == map[p].hash)
 				return map[p].value;
 			else if (map[p].state == BucketState::FREE)
-				return nullptr;
+				return NullValue;
 			p = (p + 1) & mask;  // If the state is REMOVED, we just keep on walking. 
 			if (p == pos)
 				Crash();
 		}
-		return nullptr;
+		return NullValue;
 	}
 
 	// Returns false if we already had the key! Which is a bit different.
diff --git a/GPU/D3D11/DrawEngineD3D11.h b/GPU/D3D11/DrawEngineD3D11.h
index cbc3493443..3a7d347932 100644
--- a/GPU/D3D11/DrawEngineD3D11.h
+++ b/GPU/D3D11/DrawEngineD3D11.h
@@ -167,7 +167,7 @@ private:
 	ID3D11DeviceContext *context_;
 	ID3D11DeviceContext1 *context1_;
 
-	PrehashMap<VertexArrayInfoD3D11 *> vai_;
+	PrehashMap<VertexArrayInfoD3D11 *, nullptr> vai_;
 
 	struct InputLayoutKey {
 		D3D11VertexShader *vshader;
@@ -181,7 +181,7 @@ private:
 		}
 	};
 
-	DenseHashMap<InputLayoutKey, ID3D11InputLayout *> inputLayoutMap_;
+	DenseHashMap<InputLayoutKey, ID3D11InputLayout *, nullptr> inputLayoutMap_;
 
 	// Other
 	ShaderManagerD3D11 *shaderManager_ = nullptr;
diff --git a/GPU/Directx9/DrawEngineDX9.h b/GPU/Directx9/DrawEngineDX9.h
index cd7640c06e..4c4f96acc3 100644
--- a/GPU/Directx9/DrawEngineDX9.h
+++ b/GPU/Directx9/DrawEngineDX9.h
@@ -154,8 +154,8 @@ private:
 
 	LPDIRECT3DDEVICE9 device_ = nullptr;
 
-	PrehashMap<VertexArrayInfoDX9 *> vai_;
-	DenseHashMap<u32, IDirect3DVertexDeclaration9 *> vertexDeclMap_;
+	PrehashMap<VertexArrayInfoDX9 *, nullptr> vai_;
+	DenseHashMap<u32, IDirect3DVertexDeclaration9 *, nullptr> vertexDeclMap_;
 
 	// SimpleVertex
 	IDirect3DVertexDeclaration9* transformedVertexDecl_ = nullptr;
diff --git a/GPU/GLES/DrawEngineGLES.h b/GPU/GLES/DrawEngineGLES.h
index 355cd9e66a..02613af41c 100644
--- a/GPU/GLES/DrawEngineGLES.h
+++ b/GPU/GLES/DrawEngineGLES.h
@@ -166,7 +166,7 @@ private:
 
 	void MarkUnreliable(VertexArrayInfo *vai);
 
-	PrehashMap<VertexArrayInfo *> vai_;
+	PrehashMap<VertexArrayInfo *, nullptr> vai_;
 
 	// Vertex buffer objects
 	// Element buffer objects
diff --git a/GPU/Vulkan/DrawEngineVulkan.h b/GPU/Vulkan/DrawEngineVulkan.h
index 1f0f6a6859..22d2fd8df9 100644
--- a/GPU/Vulkan/DrawEngineVulkan.h
+++ b/GPU/Vulkan/DrawEngineVulkan.h
@@ -197,7 +197,7 @@ private:
 	VulkanPipeline *lastPipeline_;
 	VkDescriptorSet lastDs_ = VK_NULL_HANDLE;
 
-	PrehashMap<VertexArrayInfoVulkan *> vai_;
+	PrehashMap<VertexArrayInfoVulkan *, nullptr> vai_;
 	VulkanPushBuffer *vertexCache_;
 	int decimationCounter_ = 0;
 
@@ -228,7 +228,7 @@ private:
 		VulkanPushBuffer *pushVertex;
 		VulkanPushBuffer *pushIndex;
 		// We do rolling allocation and reset instead of caching across frames. That we might do later.
-		DenseHashMap<DescriptorSetKey, VkDescriptorSet> descSets;
+		DenseHashMap<DescriptorSetKey, VkDescriptorSet, VK_NULL_HANDLE> descSets;
 
 		void Destroy(VulkanContext *vulkan);
 	};
diff --git a/GPU/Vulkan/PipelineManagerVulkan.h b/GPU/Vulkan/PipelineManagerVulkan.h
index 59c95694b7..a564f82a0e 100644
--- a/GPU/Vulkan/PipelineManagerVulkan.h
+++ b/GPU/Vulkan/PipelineManagerVulkan.h
@@ -97,7 +97,7 @@ public:
 	std::vector<std::string> DebugGetObjectIDs(DebugShaderType type);
 
 private:
-	DenseHashMap<VulkanPipelineKey, VulkanPipeline *> pipelines_;
+	DenseHashMap<VulkanPipelineKey, VulkanPipeline *, nullptr> pipelines_;
 	VkPipelineCache pipelineCache_;
 	VulkanContext *vulkan_;
 };