class labels timestep embeddings projection dtype cast (#3137)

This mimics the dtype cast for the standard time embeddings

src/diffusers/models/unet_2d_condition.py

@@ -659,7 +659,7 @@ class UNet2DConditionModel(ModelMixin, ConfigMixin, UNet2DConditionLoadersMixin)
 
         t_emb = self.time_proj(timesteps)
 
-        # timesteps does not contain any weights and will always return f32 tensors
+        # `Timesteps` does not contain any weights and will always return f32 tensors
         # but time_embedding might actually be running in fp16. so we need to cast here.
         # there might be better ways to encapsulate this.
         t_emb = t_emb.to(dtype=self.dtype)
@@ -673,6 +673,10 @@ class UNet2DConditionModel(ModelMixin, ConfigMixin, UNet2DConditionLoadersMixin)
             if self.config.class_embed_type == "timestep":
                 class_labels = self.time_proj(class_labels)
 
+                # `Timesteps` does not contain any weights and will always return f32 tensors
+                # there might be better ways to encapsulate this.
+                class_labels = class_labels.to(dtype=sample.dtype)
+
             class_emb = self.class_embedding(class_labels).to(dtype=self.dtype)
 
             if self.config.class_embeddings_concat:

src/diffusers/pipelines/versatile_diffusion/modeling_text_unet.py

@@ -756,7 +756,7 @@ class UNetFlatConditionModel(ModelMixin, ConfigMixin):
 
         t_emb = self.time_proj(timesteps)
 
-        # timesteps does not contain any weights and will always return f32 tensors
+        # `Timesteps` does not contain any weights and will always return f32 tensors
         # but time_embedding might actually be running in fp16. so we need to cast here.
         # there might be better ways to encapsulate this.
         t_emb = t_emb.to(dtype=self.dtype)
@@ -770,6 +770,10 @@ class UNetFlatConditionModel(ModelMixin, ConfigMixin):
             if self.config.class_embed_type == "timestep":
                 class_labels = self.time_proj(class_labels)
 
+                # `Timesteps` does not contain any weights and will always return f32 tensors
+                # there might be better ways to encapsulate this.
+                class_labels = class_labels.to(dtype=sample.dtype)
+
             class_emb = self.class_embedding(class_labels).to(dtype=self.dtype)
 
             if self.config.class_embeddings_concat: