Pass the llvm IR pointer value and offset to the constructor of

MachinePointerInfo when getStore is called to create a node that stores an
argument passed in register to the stack. Without this change, the post RA 
scheduler will fail to discover the dependencies between the stores
instructions and the instructions that load from a structure passed by value. 

The link to the related discussion is here:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-March/048055.html

llvm-svn: 153499

1 files changed, 13 insertions, 9 deletions

diff --git a/llvm/lib/Target/Mips/MipsISelLowering.cpp b/llvm/lib/Target/Mips/MipsISelLowering.cpp
index f7da0ec626a..eb0e8aefaba 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsISelLowering.cpp
@@ -2545,7 +2545,8 @@ MipsTargetLowering::LowerCallResult(SDValue Chain, SDValue InFlag,
 static void ReadByValArg(MachineFunction &MF, SDValue Chain, DebugLoc dl,
                          std::vector<SDValue>& OutChains,
                          SelectionDAG &DAG, unsigned NumWords, SDValue FIN,
-                         const CCValAssign &VA, const ISD::ArgFlagsTy& Flags) {
+                         const CCValAssign &VA, const ISD::ArgFlagsTy& Flags,
+                         const Argument *FuncArg) {
   unsigned LocMem = VA.getLocMemOffset();
   unsigned FirstWord = LocMem / 4;
 
@@ -2560,8 +2561,8 @@ static void ReadByValArg(MachineFunction &MF, SDValue Chain, DebugLoc dl,
     SDValue StorePtr = DAG.getNode(ISD::ADD, dl, MVT::i32, FIN,
                                    DAG.getConstant(i * 4, MVT::i32));
     SDValue Store = DAG.getStore(Chain, dl, DAG.getRegister(Reg, MVT::i32),
-                                 StorePtr, MachinePointerInfo(), false,
-                                 false, 0);
+                                 StorePtr, MachinePointerInfo(FuncArg, i * 4),
+                                 false, false, 0);
     OutChains.push_back(Store);
   }
 }
@@ -2573,7 +2574,7 @@ CopyMips64ByValRegs(MachineFunction &MF, SDValue Chain, DebugLoc dl,
                     const CCValAssign &VA, const ISD::ArgFlagsTy& Flags,
                     MachineFrameInfo *MFI, bool IsRegLoc,
                     SmallVectorImpl<SDValue> &InVals, MipsFunctionInfo *MipsFI,
-                    EVT PtrTy) {
+                    EVT PtrTy, const Argument *FuncArg) {
   const uint16_t *Reg = Mips64IntRegs + 8;
   int FOOffset; // Frame object offset from virtual frame pointer.
 
@@ -2597,8 +2598,8 @@ CopyMips64ByValRegs(MachineFunction &MF, SDValue Chain, DebugLoc dl,
     SDValue StorePtr = DAG.getNode(ISD::ADD, dl, PtrTy, FIN,
                                    DAG.getConstant(I * 8, PtrTy));
     SDValue Store = DAG.getStore(Chain, dl, DAG.getRegister(VReg, MVT::i64),
-                                 StorePtr, MachinePointerInfo(), false,
-                                 false, 0);
+                                 StorePtr, MachinePointerInfo(FuncArg, I * 8),
+                                 false, false, 0);
     OutChains.push_back(Store);
   }
 
@@ -2634,9 +2635,11 @@ MipsTargetLowering::LowerFormalArguments(SDValue Chain,
   else
     CCInfo.AnalyzeFormalArguments(Ins, CC_Mips);
 
+  Function::const_arg_iterator FuncArg =
+    DAG.getMachineFunction().getFunction()->arg_begin();
   int LastFI = 0;// MipsFI->LastInArgFI is 0 at the entry of this function.
 
-  for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
+  for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i, ++FuncArg) {
     CCValAssign &VA = ArgLocs[i];
     EVT ValVT = VA.getValVT();
     ISD::ArgFlagsTy Flags = Ins[i].Flags;
@@ -2651,11 +2654,12 @@ MipsTargetLowering::LowerFormalArguments(SDValue Chain,
                                         true);
         SDValue FIN = DAG.getFrameIndex(LastFI, getPointerTy());
         InVals.push_back(FIN);
-        ReadByValArg(MF, Chain, dl, OutChains, DAG, NumWords, FIN, VA, Flags);
+        ReadByValArg(MF, Chain, dl, OutChains, DAG, NumWords, FIN, VA, Flags,
+                     &*FuncArg);
       } else // N32/64
         LastFI = CopyMips64ByValRegs(MF, Chain, dl, OutChains, DAG, VA, Flags,
                                      MFI, IsRegLoc, InVals, MipsFI,
-                                     getPointerTy());
+                                     getPointerTy(), &*FuncArg);
       continue;
     }