From 4f0d8e4018d50c5796660a4fa167763f46259646 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Fri, 13 Jan 2006 17:48:44 +0000
Subject: [PATCH] If a target specified a stack pointer with
 setStackPointerRegisterToSaveRestore, lower STACKSAVE/STACKRESTORE into a
 copy from/to that register.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25276 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/LegalizeDAG.cpp | 26 +++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 5ea8b3dd1e8..af7fce423f3 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -1453,10 +1453,20 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
       AddLegalizedOperand(SDOperand(Node, 1), Result.getValue(1));
       return Result.getValue(Op.ResNo);
     case TargetLowering::Expand:
-      Tmp1 = DAG.getNode(ISD::UNDEF, Node->getValueType(0));
-      AddLegalizedOperand(SDOperand(Node, 0), Tmp1);
-      AddLegalizedOperand(SDOperand(Node, 1), Node->getOperand(0));
-      return Op.ResNo ? Node->getOperand(0) : Tmp1;
+      // Expand to CopyFromReg if the target set 
+      // StackPointerRegisterToSaveRestore.
+      if (unsigned SP = TLI.getStackPointerRegisterToSaveRestore()) {
+        Tmp1 = DAG.getCopyFromReg(Node->getOperand(0), SP, 
+                                  Node->getValueType(0));
+        AddLegalizedOperand(SDOperand(Node, 0), Tmp1);
+        AddLegalizedOperand(SDOperand(Node, 1), Tmp1.getValue(1));
+        return Tmp1.getValue(Op.ResNo);
+      } else {
+        Tmp1 = DAG.getNode(ISD::UNDEF, Node->getValueType(0));
+        AddLegalizedOperand(SDOperand(Node, 0), Tmp1);
+        AddLegalizedOperand(SDOperand(Node, 1), Node->getOperand(0));
+        return Op.ResNo ? Node->getOperand(0) : Tmp1;
+      }
     }
     
   case ISD::STACKRESTORE:
@@ -1478,7 +1488,13 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
     case TargetLowering::Legal:
       break;
     case TargetLowering::Expand:
-      Result = Tmp1;
+      // Expand to CopyToReg if the target set 
+      // StackPointerRegisterToSaveRestore.
+      if (unsigned SP = TLI.getStackPointerRegisterToSaveRestore()) {
+        Result = DAG.getCopyToReg(Tmp1, SP, Tmp2);
+      } else {
+        Result = Tmp1;
+      }
       break;
     }
     break;