ReleaseNotes: start off a 'Changes to X86' section

git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_38@260648 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index bbf2dd0f39f82d77a87caa2fb7ed1446507bac7f..aa8ebfd8e8cbd6a0aaf8be82d1ccabc5abcb9609 100644 (file)
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -108,6 +108,18 @@ Non-comprehensive list of changes in this release
 
    Makes programs 10x faster by doing Special New Thing.
 
 
    Makes programs 10x faster by doing Special New Thing.
 

+Changes to the X86 and X86-64 Targets
+-------------------------------------
+
+* Smaller code for materializing 32-bit 1 and -1 constants at ``-Os``.
+
+* More efficient code for wide integer compares. (E.g. 64-bit compares
+  on 32-bit targets.)
+
+* Tail call support for ``thiscall``, ``stdcall`, ``vectorcall``, and
+  ``fastcall`` functions.
+
+

 Changes to the ARM Backend
 --------------------------
 
 Changes to the ARM Backend
 --------------------------