Added some isel ideas.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24757 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt
index 57aec86d2e5a7427589dd777da65d2d8f8052f0c..6e23fca25c62a5b853b8bfd91deb05e01d5686b4 100644 (file)
--- a/lib/Target/X86/README.txt
+++ b/lib/Target/X86/README.txt
@@ -88,3 +88,17 @@ into:
         movzbl  %dil, %eax
         xorl    $1, %eax
         ret
+
+//===---------------------------------------------------------------------===//
+
+Some isel ideas:
+
+1. Dynamic programming based approach when compile time if not an
+   issue.
+2. Code duplication (addressing mode) during isel.
+3. Other ideas from "Register-Sensitive Selection, Duplication, and
+   Sequencing of Instructions".
+
+//===---------------------------------------------------------------------===//
+
+Should we promote i16 to i32 to avoid partial register update stalls?