From 223fd6efc86ec79bbe26a92e780976ae527f2f61 Mon Sep 17 00:00:00 2001
From: Richard Osborne <richard@xmos.com>
Date: Fri, 14 Nov 2008 15:59:19 +0000
Subject: [PATCH] [XCore] Fix expansion of 64 bit add/sub. Don't custom expand
 these operations if ladd/lsub are not available on the current subtarget.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59305 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/XCore/XCoreISelLowering.cpp | 32 +++++++++-----------------
 lib/Target/XCore/XCoreISelLowering.h   |  4 ++--
 test/CodeGen/XCore/addsub64.ll         | 12 ++++++++++
 3 files changed, 25 insertions(+), 23 deletions(-)
 create mode 100644 test/CodeGen/XCore/addsub64.ll

diff --git a/lib/Target/XCore/XCoreISelLowering.cpp b/lib/Target/XCore/XCoreISelLowering.cpp
index 765e6182b84..822550aef7e 100644
--- a/lib/Target/XCore/XCoreISelLowering.cpp
+++ b/lib/Target/XCore/XCoreISelLowering.cpp
@@ -88,9 +88,10 @@ XCoreTargetLowering::XCoreTargetLowering(XCoreTargetMachine &XTM)
   setOperationAction(ISD::SELECT_CC, MVT::Other, Expand);
   
   // 64bit
-  setOperationAction(ISD::ADD, MVT::i64, Custom);
-  setOperationAction(ISD::SUB, MVT::i64, Custom);
-  
+  if (!Subtarget.isXS1A()) {
+    setOperationAction(ISD::ADD, MVT::i64, Custom);
+    setOperationAction(ISD::SUB, MVT::i64, Custom);
+  }
   if (Subtarget.isXS1A()) {
     setOperationAction(ISD::SMUL_LOHI, MVT::i32, Expand);
   }
@@ -161,7 +162,6 @@ LowerOperation(SDValue Op, SelectionDAG &DAG) {
   // FIXME: Remove these when LegalizeDAGTypes lands.
   case ISD::ADD:
   case ISD::SUB:              return SDValue(ExpandADDSUB(Op.getNode(), DAG),0);
-  
   case ISD::FRAMEADDR:        return LowerFRAMEADDR(Op, DAG);
   default:
     assert(0 && "unimplemented operand");
@@ -169,15 +169,16 @@ LowerOperation(SDValue Op, SelectionDAG &DAG) {
   }
 }
 
+/// ReplaceNodeResults - Provide custom lowering hooks for nodes with illegal
+/// result types.
 SDNode *XCoreTargetLowering::
-ExpandOperationResult(SDNode *N, SelectionDAG &DAG) {
+ReplaceNodeResults(SDNode *N, SelectionDAG &DAG) {
   switch (N->getOpcode()) {
-  case ISD::SUB:
-  case ISD::ADD:
-    return ExpandADDSUB(N, DAG);
   default:
-    assert(0 && "Wasn't expecting to be able to lower this!");
+    assert(0 && "Don't know how to custom expand this!");
     return NULL;
+  case ISD::ADD:
+  case ISD::SUB: return ExpandADDSUB(N, DAG);
   }
 }
 
@@ -301,6 +302,7 @@ ExpandADDSUB(SDNode *N, SelectionDAG &DAG)
   assert(N->getValueType(0) == MVT::i64 &&
          (N->getOpcode() == ISD::ADD || N->getOpcode() == ISD::SUB) &&
         "Unknown operand to lower!");
+  assert(!Subtarget.isXS1A() && "Cannot custom lower ADD/SUB on xs1a");
   
   // Extract components
   SDValue LHSL = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32, N->getOperand(0),
@@ -313,18 +315,6 @@ ExpandADDSUB(SDNode *N, SelectionDAG &DAG)
                              DAG.getConstant(1, MVT::i32));
   
   // Expand
-  if (Subtarget.isXS1A()) {
-    SDValue Lo = DAG.getNode(N->getOpcode(), MVT::i32, LHSL, RHSL);
-    
-    ISD::CondCode CarryCC = (N->getOpcode() == ISD::ADD) ? ISD::SETULT :
-                                                           ISD::SETUGT;
-    SDValue Carry = DAG.getSetCC(MVT::i32, Lo, LHSL, CarryCC);
-    
-    SDValue Hi = DAG.getNode(N->getOpcode(), MVT::i32, LHSH, Carry);
-    Hi = DAG.getNode(N->getOpcode(), MVT::i32, Hi, RHSH);
-    // Merge the pieces
-    return DAG.getNode(ISD::BUILD_PAIR, MVT::i64, Lo, Hi).getNode();
-  }
   unsigned Opcode = (N->getOpcode() == ISD::ADD) ? XCoreISD::LADD :
                                                    XCoreISD::LSUB;
   SDValue Zero = DAG.getConstant(0, MVT::i32);
diff --git a/lib/Target/XCore/XCoreISelLowering.h b/lib/Target/XCore/XCoreISelLowering.h
index d2622c1c7c0..0ce1c76efb5 100644
--- a/lib/Target/XCore/XCoreISelLowering.h
+++ b/lib/Target/XCore/XCoreISelLowering.h
@@ -67,8 +67,8 @@ namespace llvm {
 
     /// LowerOperation - Provide custom lowering hooks for some operations.
     virtual SDValue LowerOperation(SDValue Op, SelectionDAG &DAG);
-  
-    virtual SDNode *ExpandOperationResult(SDNode *N, SelectionDAG &DAG);
+
+    virtual SDNode *ReplaceNodeResults(SDNode *N, SelectionDAG &DAG);
 
     /// getTargetNodeName - This method returns the name of a target specific 
     //  DAG node.
diff --git a/test/CodeGen/XCore/addsub64.ll b/test/CodeGen/XCore/addsub64.ll
new file mode 100644
index 00000000000..41224fca1cc
--- /dev/null
+++ b/test/CodeGen/XCore/addsub64.ll
@@ -0,0 +1,12 @@
+; RUN: llvm-as < %s | llc -march=xcore -mcpu=xs1b-generic > %t1.s
+; RUN: grep ladd %t1.s | count 2
+; RUN: grep lsub %t1.s | count 2
+define i64 @add64(i64 %a, i64 %b) {
+	%result = add i64 %a, %b
+	ret i64 %result
+}
+
+define i64 @sub64(i64 %a, i64 %b) {
+	%result = sub i64 %a, %b
+	ret i64 %result
+}