From 5fd79ce459a33a62883a263cd15a119dd8df7d41 Mon Sep 17 00:00:00 2001
From: xumingkuan <xumingkuan0721@126.com>
Date: Tue, 29 Dec 2020 13:20:01 +0800
Subject: [PATCH] [opt] Algebraic simplification for bit_and with 0

---
 taichi/transforms/alg_simp.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/taichi/transforms/alg_simp.cpp b/taichi/transforms/alg_simp.cpp
index bf7ba3e28ee6f..f0d95e9f619f0 100644
--- a/taichi/transforms/alg_simp.cpp
+++ b/taichi/transforms/alg_simp.cpp
@@ -220,6 +220,9 @@ class AlgSimp : public BasicStmtVisitor {
         // -1 & a -> a
         stmt->replace_with(stmt->rhs);
         modifier.erase(stmt);
+      } else if (alg_is_zero(lhs) || alg_is_zero(rhs)) {
+        // 0 & a -> 0, a & 0 -> 0
+        replace_with_zero(stmt);
       } else if (irpass::analysis::same_value(stmt->lhs, stmt->rhs)) {
         // a & a -> a
         stmt->replace_with(stmt->lhs);