A new entry

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28419 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt
index 34055ddafb80f7bc3c4928747780cd5c8c20f3df..2b7989bbe0531ad0a451f283eb82709d63f5ee8f 100644 (file)
--- a/lib/Target/X86/README.txt
+++ b/lib/Target/X86/README.txt
@@ -577,3 +577,13 @@ nicer, while still handling the hard cases.
 
 //===---------------------------------------------------------------------===//
 
+Some ideas for instruction selection code simplification: 1. A pre-pass to
+determine which chain producing node can or cannot be folded. The generated
+isel code would then use the information. 2. The same pre-pass can force
+ordering of TokenFactor operands to allow load / store folding. 3. During isel,
+instead of recursively going up the chain operand chain, mark the chain operand
+as available and put it in some work list. Select other nodes in the normal
+manner. The chain operands are selected after all other nodes are selected. Uses
+of chain nodes are modified after instruction selection is completed.
+
+