From 709d19fb6677d8f31c7c9d2457f3647cb09b1941 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Wed, 12 Mar 2008 07:52:15 +0000 Subject: [PATCH] Document an implementation detail about EXTRACT_SUBREG and INSERT_SUBREG sub-register operand. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48283 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/CodeGen/SelectionDAGNodes.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h index b2c354dae1d..49012b4b0e7 100644 --- a/include/llvm/CodeGen/SelectionDAGNodes.h +++ b/include/llvm/CodeGen/SelectionDAGNodes.h @@ -320,6 +320,9 @@ namespace ISD { // EXTRACT_SUBREG - This node is used to extract a sub-register value. // This node takes a superreg and a constant sub-register index as operands. + // Note sub-register indices must be increasing. That is, if the + // sub-register index of a 8-bit sub-register is N, then the index for a + // 16-bit sub-register must be at least N+1. EXTRACT_SUBREG, // INSERT_SUBREG - This node is used to insert a sub-register value.