--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -613,12 +613,6 @@
       ]
     }

-    # The performance improvement does not seem worth the risk. See
-    # https://crbug.com/484082200 for background and https://crrev.com/c/7593035
-    # for discussion.
-    if (!is_wasm) {
-      cflags += [ "-fno-lifetime-dse" ]
-    }

     # TODO(hans): Remove this once Clang generates better optimized debug info
     # by default. https://crbug.com/765793
@@ -1881,11 +1875,6 @@
       "-fsanitize=array-bounds",
       "-fsanitize-trap=array-bounds",

-      # Some code users feature detection to determine if UBSAN (or any
-      # sanitizer) is enabled, they then do expensive debug like operations. We
-      # want to suppress this behaviour since we want to keep performance costs
-      # as low as possible while having these checks.
-      "-fsanitize-ignore-for-ubsan-feature=array-bounds",

       # Because we've enabled array-bounds sanitizing we also want to suppress
       # the related warning about "unsafe-buffer-usage-in-static-sized-array",