Add elementwise fusions (#9495)

* Add elementwise fusions

* Add addcmul pattern to Qwen

comfy/ldm/modules/diffusionmodules/mmdit.py

@@ -109,7 +109,7 @@ class PatchEmbed(nn.Module):
 def modulate(x, shift, scale):
     if shift is None:
         shift = torch.zeros_like(scale)
-    return x * (1 + scale.unsqueeze(1)) + shift.unsqueeze(1)
+    return torch.addcmul(shift.unsqueeze(1), x, 1+ scale.unsqueeze(1))
 
 
 #################################################################################
@@ -564,10 +564,7 @@ class DismantledBlock(nn.Module):
         assert not self.pre_only
         attn1 = self.attn.post_attention(attn)
         attn2 = self.attn2.post_attention(attn2)
-        out1 = gate_msa.unsqueeze(1) * attn1
+        x = gate_cat(x, gate_msa, gate_msa2, attn1, attn2)
-        out2 = gate_msa2.unsqueeze(1) * attn2
-        x = x + out1
-        x = x + out2
         x = x + gate_mlp.unsqueeze(1) * self.mlp(
             modulate(self.norm2(x), shift_mlp, scale_mlp)
         )
@@ -594,6 +591,11 @@ class DismantledBlock(nn.Module):
             )
             return self.post_attention(attn, *intermediates)
 
+def gate_cat(x, gate_msa, gate_msa2, attn1, attn2):
+    out1 = gate_msa.unsqueeze(1) * attn1
+    out2 = gate_msa2.unsqueeze(1) * attn2
+    x = torch.stack([x, out1, out2], dim=0).sum(dim=0)
+    return x
 
 def block_mixing(*args, use_checkpoint=True, **kwargs):
     if use_checkpoint:

comfy/ldm/qwen_image/model.py

@@ -214,9 +214,9 @@ class QwenImageTransformerBlock(nn.Module):
             operations=operations,
         )
 
-    def _modulate(self, x, mod_params):
+    def _modulate(self, x: torch.Tensor, mod_params: torch.Tensor) -> Tuple[torch.Tensor, torch.Tensor]:
-        shift, scale, gate = mod_params.chunk(3, dim=-1)
+        shift, scale, gate = torch.chunk(mod_params, 3, dim=-1)
-        return x * (1 + scale.unsqueeze(1)) + shift.unsqueeze(1), gate.unsqueeze(1)
+        return torch.addcmul(shift.unsqueeze(1), x, 1 + scale.unsqueeze(1)), gate.unsqueeze(1)
 
     def forward(
         self,
@@ -248,11 +248,11 @@ class QwenImageTransformerBlock(nn.Module):
 
         img_normed2 = self.img_norm2(hidden_states)
         img_modulated2, img_gate2 = self._modulate(img_normed2, img_mod2)
-        hidden_states = hidden_states + img_gate2 * self.img_mlp(img_modulated2)
+        hidden_states = torch.addcmul(hidden_states, img_gate2, self.img_mlp(img_modulated2))
 
         txt_normed2 = self.txt_norm2(encoder_hidden_states)
         txt_modulated2, txt_gate2 = self._modulate(txt_normed2, txt_mod2)
-        encoder_hidden_states = encoder_hidden_states + txt_gate2 * self.txt_mlp(txt_modulated2)
+        encoder_hidden_states = torch.addcmul(encoder_hidden_states, txt_gate2, self.txt_mlp(txt_modulated2))
 
         return encoder_hidden_states, hidden_states
 
@@ -275,7 +275,7 @@ class LastLayer(nn.Module):
     def forward(self, x: torch.Tensor, conditioning_embedding: torch.Tensor) -> torch.Tensor:
         emb = self.linear(self.silu(conditioning_embedding))
         scale, shift = torch.chunk(emb, 2, dim=1)
-        x = self.norm(x) * (1 + scale)[:, None, :] + shift[:, None, :]
+        x = torch.addcmul(shift[:, None, :], self.norm(x), (1 + scale)[:, None, :])
         return x
 
 

comfy/ldm/wan/model.py

@@ -148,8 +148,8 @@ WAN_CROSSATTENTION_CLASSES = {
 
 def repeat_e(e, x):
     repeats = 1
-    if e.shape[1] > 1:
+    if e.size(1) > 1:
-        repeats = x.shape[1] // e.shape[1]
+        repeats = x.size(1) // e.size(1)
     if repeats == 1:
         return e
     return torch.repeat_interleave(e, repeats, dim=1)
@@ -219,15 +219,15 @@ class WanAttentionBlock(nn.Module):
 
         # self-attention
         y = self.self_attn(
-            self.norm1(x) * (1 + repeat_e(e[1], x)) + repeat_e(e[0], x),
+            torch.addcmul(repeat_e(e[0], x), self.norm1(x), 1 + repeat_e(e[1], x)),
             freqs)
 
-        x = x + y * repeat_e(e[2], x)
+        x = torch.addcmul(x, y, repeat_e(e[2], x))
 
         # cross-attention & ffn
         x = x + self.cross_attn(self.norm3(x), context, context_img_len=context_img_len)
-        y = self.ffn(self.norm2(x) * (1 + repeat_e(e[4], x)) + repeat_e(e[3], x))
+        y = self.ffn(torch.addcmul(repeat_e(e[3], x), self.norm2(x), 1 + repeat_e(e[4], x)))
-        x = x + y * repeat_e(e[5], x)
+        x = torch.addcmul(x, y, repeat_e(e[5], x))
         return x
 
 
@@ -342,7 +342,7 @@ class Head(nn.Module):
         else:
             e = (comfy.model_management.cast_to(self.modulation, dtype=x.dtype, device=x.device).unsqueeze(0) + e.unsqueeze(2)).unbind(2)
 
-        x = (self.head(self.norm(x) * (1 + repeat_e(e[1], x)) + repeat_e(e[0], x)))
+        x = (self.head(torch.addcmul(repeat_e(e[0], x), self.norm(x), 1 + repeat_e(e[1], x))))
         return x