add a note
llvm-svn: 34837
diff --git a/llvm/lib/Target/X86/README.txt b/llvm/lib/Target/X86/README.txt
index 554c49b..1c067f5 100644
--- a/llvm/lib/Target/X86/README.txt
+++ b/llvm/lib/Target/X86/README.txt
@@ -920,3 +920,25 @@
Though this probably isn't worth it.
//===---------------------------------------------------------------------===//
+
+We need to teach the codegen to convert two-address INC instructions to LEA
+when the flags are dead. For example, on X86-64, compile:
+
+int foo(int A, int B) {
+ return A+1;
+}
+
+to:
+
+_foo:
+ leal 1(%edi), %eax
+ ret
+
+instead of:
+
+_foo:
+ incl %edi
+ movl %edi, %eax
+ ret
+
+//===---------------------------------------------------------------------===//