Add a note about x86 register coallescing

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26920 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt
index 429d159fce4557ee1d2b6f945ca7f0b3bce00f18..d9aaecbb96d89d2578cf3e58de10eba5ba06ca1a 100644 (file)
--- a/lib/Target/X86/README.txt
+++ b/lib/Target/X86/README.txt
@@ -644,3 +644,5 @@ void minf(float a, float b, float *X) {
 
 //===---------------------------------------------------------------------===//
 
+Teach the coallescer to coales vregs of different register classes. e.g. FR32 /
+FR64 to VR128.