From 1112e2526e37db215366a5fb8edb93b1af733dc4 Mon Sep 17 00:00:00 2001
From: Nora Belrose <39116809+norabelrose@users.noreply.github.com>
Date: Fri, 23 Apr 2021 11:22:27 -0700
Subject: [PATCH] [PYTHON] Fix variable referenced before assignment error in
 blocksparse matmul backward (#90)

---
 python/triton/ops/blocksparse/matmul.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/python/triton/ops/blocksparse/matmul.py b/python/triton/ops/blocksparse/matmul.py
index 50af3c564..99a4d0281 100644
--- a/python/triton/ops/blocksparse/matmul.py
+++ b/python/triton/ops/blocksparse/matmul.py
@@ -560,7 +560,9 @@ class _matmul(torch.autograd.Function):
     def backward(ctx, dc):
         # saved for backward
         a, b = ctx.saved_tensors
+        da, db = None, None
         mode = ctx.mode
+
         # gradients w.r.t. a
         if ctx.needs_input_grad[0]:
             mode_da = mode[1] + mode[0] + mode[2]