Add note on theoretical IRgen improvement.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@67024 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/README.txt b/lib/CodeGen/README.txt
index e4508c7b82a0999b8fc890aff9bae97ce55c15c5..f60cd03ad6490fe476dbe45bcdcef1ba10498daf 100644 (file)
--- a/lib/CodeGen/README.txt
+++ b/lib/CodeGen/README.txt
@@ -53,3 +53,13 @@ still generates a call to printf. This doesn't occur much in real
 code, but would still be nice to clean up.
 
 //===---------------------------------------------------------------------===//
+
+Deferred generation of statics incurs some additional
+overhead. Currently it is even possible to construct test cases with
+O(N^2) behavior! For at least simple cases where we can tell a global
+is used, it is probably not worth deferring it. This doesn't solve the
+O(N^2) cases, ,though...
+
+PR3810
+
+//===---------------------------------------------------------------------===//