From 1cfa05e66c090ed6b57e7631b4935f2a7f5a6aad Mon Sep 17 00:00:00 2001
From: Hiroshi Horii <hhorii@users.noreply.github.com>
Date: Tue, 20 Jul 2021 23:43:47 +0900
Subject: [PATCH] fix a bug to generate a diagonal gate in the end of circuit
 (#1294)

---
 src/transpile/fusion.hpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/transpile/fusion.hpp b/src/transpile/fusion.hpp
index e5266d6e1d..a8105baed1 100644
--- a/src/transpile/fusion.hpp
+++ b/src/transpile/fusion.hpp
@@ -658,8 +658,10 @@ bool DiagonalFusion::aggregate_operations(oplist_t& ops,
       continue;
 
     std::vector<uint_t> fusing_op_idxs;
-    for (; op_idx < next_diagonal_start; ++op_idx)
+    while(op_idx < next_diagonal_start && op_idx < fusion_end) {
       fusing_op_idxs.push_back(op_idx);
+      ++op_idx;
+    }
 
     --op_idx;
     allocate_new_operation(ops, op_idx, fusing_op_idxs, method, true);