port whatsnew, asv from pandas-dev#38148

Author: jbrockmendel

asv_bench/benchmarks/indexing.py

@@ -358,6 +358,14 @@ def time_assign_with_setitem(self):
         for i in range(100):
             self.df[i] = np.random.randn(self.N)
 
+    def time_assign_list_like_with_setitem(self):
+        np.random.seed(1234)
+        self.df[list(range(100))] = np.random.randn(self.N, 100)
+
+    def time_assign_list_of_columns_concat(self):
+        df = DataFrame(np.random.randn(self.N, 100))
+        concat([self.df, df], axis=1)
+
 
 class ChainIndexing:
 

doc/source/whatsnew/v1.1.5.rst

@@ -25,6 +25,7 @@ Fixed regressions
 - Fixed regression in ``df.groupby(..).rolling(..)`` with the resulting :class:`MultiIndex` when grouping by a label that is in the index (:issue:`37641`)
 - Fixed regression in :meth:`DataFrame.fillna` not filling ``NaN`` after other operations such as :meth:`DataFrame.pivot` (:issue:`36495`).
 - Fixed performance regression in ``df.groupby(..).rolling(..)`` (:issue:`38038`)
+- Fixed performance regression for :meth:`DataFrame.__setitem__` with list-like indexers (:issue:`37954`)
 - Fixed regression in :meth:`MultiIndex.intersection` returning duplicates when at least one of the indexes had duplicates (:issue:`36915`)
 
 .. ---------------------------------------------------------------------------