add note about possible GEP improvement with fields of size 0.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62925 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/README.txt b/lib/Target/README.txt
index c679fd83c0daccfa44ae210592d635c4fb3352bb..78dcb12581c699ff3271d73fce612b6d8ca5b386 100644 (file)
--- a/lib/Target/README.txt
+++ b/lib/Target/README.txt
@@ -1683,3 +1683,9 @@ Always foldable for odd constants, what is the rule for even?
 
 //===---------------------------------------------------------------------===//
 
+PR 3381: GEP to field of size 0 inside a struct could be turned into GEP
+for next field in struct (which is at same address).
+
+For example: store of float into { {{}}, float } could be turned into a store to
+the float directly.
+