Issue description:

SchedulerDAGInstrs::buildSchedGraph ignores dependencies between FixedStack
objects and byval parameters. So loading byval parameters from stack may be
inserted *before* it will be stored, since these operations are treated as
independent.

Fix:
Currently ARMTargetLowering::LowerFormalArguments saves byval registers with
FixedStack MachinePointerInfo. To fix the problem we need to store byval
registers with MachinePointerInfo referenced to first the "byval" parameter.

Also commit adds two new fields to the InputArg structure: Function's argument
index and InputArg's part offset in bytes relative to the start position of
Function's argument. E.g.: If function's argument is 128 bit width and it was
splitted onto 32 bit regs, then we got 4 InputArg structs with same arg index,
but different offset values. 



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165616 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 2 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index dccc2fcf25..cdebff94e5 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -6681,7 +6681,7 @@ void SelectionDAGISel::LowerArguments(const BasicBlock *LLVMBB) {
     ISD::ArgFlagsTy Flags;
     Flags.setSRet();
     EVT RegisterVT = TLI.getRegisterType(*DAG.getContext(), ValueVTs[0]);
-    ISD::InputArg RetArg(Flags, RegisterVT, true);
+    ISD::InputArg RetArg(Flags, RegisterVT, true, 0, 0);
     Ins.push_back(RetArg);
   }
 
@@ -6729,7 +6729,8 @@ void SelectionDAGISel::LowerArguments(const BasicBlock *LLVMBB) {
       EVT RegisterVT = TLI.getRegisterType(*CurDAG->getContext(), VT);
       unsigned NumRegs = TLI.getNumRegisters(*CurDAG->getContext(), VT);
       for (unsigned i = 0; i != NumRegs; ++i) {
-        ISD::InputArg MyFlags(Flags, RegisterVT, isArgValueUsed);
+        ISD::InputArg MyFlags(Flags, RegisterVT, isArgValueUsed,
+                              Idx-1, i*RegisterVT.getStoreSize());
         if (NumRegs > 1 && i == 0)
           MyFlags.Flags.setSplit();
         // if it isn't first piece, alignment must be 1