[PATCH] SelectionDAG: Pass along the original argument/element type in ISD::InputArg

[Tom Stellard]

From: Justin Holewinski <jholewinski at nvidia.com>

For some targets, it is useful to be able to look at the original
type of an argument without having to dig through the original IR.

This also fixes a bug in SelectionDAGBuilder where InputArg.PartOffset
was not taking into account the offset of structure elements.

Patch by: Justin Holewinski

Tom Stellard:
  - Changed the type of ArgVT to EVT, so it can store non-simple types
    like v3i32.
---

R600 patches which use this feature will be sent to the list shortly.

 include/llvm/Target/TargetCallingConv.h          |  8 ++++++--
 lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp | 13 ++++++++-----
 lib/CodeGen/TargetLoweringBase.cpp               |  2 +-
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/include/llvm/Target/TargetCallingConv.h b/include/llvm/Target/TargetCallingConv.h
index 1fd0bd9..9cc52a5 100644
--- a/include/llvm/Target/TargetCallingConv.h
+++ b/include/llvm/Target/TargetCallingConv.h
@@ -113,6 +113,7 @@ namespace ISD {
   struct InputArg {
     ArgFlagsTy Flags;
     MVT VT;
+    EVT ArgVT;
     bool Used;
 
     /// Index original Function's argument.
@@ -124,10 +125,11 @@ namespace ISD {
     unsigned PartOffset;
 
     InputArg() : VT(MVT::Other), Used(false) {}
-    InputArg(ArgFlagsTy flags, EVT vt, bool used,
+    InputArg(ArgFlagsTy flags, EVT vt, EVT argvt, bool used,
              unsigned origIdx, unsigned partOffs)
       : Flags(flags), Used(used), OrigArgIndex(origIdx), PartOffset(partOffs) {
       VT = vt.getSimpleVT();
+      ArgVT = argvt;
     }
   };
 
@@ -138,6 +140,7 @@ namespace ISD {
   struct OutputArg {
     ArgFlagsTy Flags;
     MVT VT;
+    EVT ArgVT;
 
     /// IsFixed - Is this a "fixed" value, ie not passed through a vararg "...".
     bool IsFixed;
@@ -151,11 +154,12 @@ namespace ISD {
     unsigned PartOffset;
 
     OutputArg() : IsFixed(false) {}
-    OutputArg(ArgFlagsTy flags, EVT vt, bool isfixed,
+    OutputArg(ArgFlagsTy flags, EVT vt, EVT argvt, bool isfixed,
               unsigned origIdx, unsigned partOffs)
       : Flags(flags), IsFixed(isfixed), OrigArgIndex(origIdx),
         PartOffset(partOffs) {
       VT = vt.getSimpleVT();
+      ArgVT = argvt;
     }
   };
 }
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 0971e8a..530e0b6 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -1268,7 +1268,7 @@ void SelectionDAGBuilder::visitRet(const ReturnInst &I) {
 
         for (unsigned i = 0; i < NumParts; ++i) {
           Outs.push_back(ISD::OutputArg(Flags, Parts[i].getValueType(),
-                                        /*isfixed=*/true, 0, 0));
+                                        VT, /*isfixed=*/true, 0, 0));
           OutVals.push_back(Parts[i]);
         }
       }
@@ -6740,6 +6740,7 @@ TargetLowering::LowerCallTo(TargetLowering::CallLoweringInfo &CLI) const {
     for (unsigned i = 0; i != NumRegs; ++i) {
       ISD::InputArg MyFlags;
       MyFlags.VT = RegisterVT;
+      MyFlags.ArgVT = VT;
       MyFlags.Used = CLI.IsReturnValueUsed;
       if (CLI.RetSExt)
         MyFlags.Flags.setSExt();
@@ -6829,7 +6830,7 @@ TargetLowering::LowerCallTo(TargetLowering::CallLoweringInfo &CLI) const {
 
       for (unsigned j = 0; j != NumParts; ++j) {
         // if it isn't first piece, alignment must be 1
-        ISD::OutputArg MyFlags(Flags, Parts[j].getValueType(),
+        ISD::OutputArg MyFlags(Flags, Parts[j].getValueType(), VT,
                                i < CLI.NumFixedArgs,
                                i, j*Parts[j].getValueType().getStoreSize());
         if (NumParts > 1 && j == 0)
@@ -6968,7 +6969,7 @@ void SelectionDAGISel::LowerArguments(const Function &F) {
     ISD::ArgFlagsTy Flags;
     Flags.setSRet();
     MVT RegisterVT = TLI->getRegisterType(*DAG.getContext(), ValueVTs[0]);
-    ISD::InputArg RetArg(Flags, RegisterVT, true, 0, 0);
+    ISD::InputArg RetArg(Flags, RegisterVT, ValueVTs[0], true, 0, 0);
     Ins.push_back(RetArg);
   }
 
@@ -6979,6 +6980,7 @@ void SelectionDAGISel::LowerArguments(const Function &F) {
     SmallVector<EVT, 4> ValueVTs;
     ComputeValueVTs(*TLI, I->getType(), ValueVTs);
     bool isArgValueUsed = !I->use_empty();
+    unsigned PartBase = 0;
     for (unsigned Value = 0, NumValues = ValueVTs.size();
          Value != NumValues; ++Value) {
       EVT VT = ValueVTs[Value];
@@ -7016,8 +7018,8 @@ void SelectionDAGISel::LowerArguments(const Function &F) {
       MVT 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,
-                              Idx-1, i*RegisterVT.getStoreSize());
+        ISD::InputArg MyFlags(Flags, RegisterVT, VT, isArgValueUsed,
+                              Idx-1, PartBase+i*RegisterVT.getStoreSize());
         if (NumRegs > 1 && i == 0)
           MyFlags.Flags.setSplit();
         // if it isn't first piece, alignment must be 1
@@ -7025,6 +7027,7 @@ void SelectionDAGISel::LowerArguments(const Function &F) {
           MyFlags.Flags.setOrigAlign(1);
         Ins.push_back(MyFlags);
       }
+      PartBase += VT.getStoreSize();
     }
   }
 
diff --git a/lib/CodeGen/TargetLoweringBase.cpp b/lib/CodeGen/TargetLoweringBase.cpp
index 7d28ed4..d0ed46e 100644
--- a/lib/CodeGen/TargetLoweringBase.cpp
+++ b/lib/CodeGen/TargetLoweringBase.cpp
@@ -1195,7 +1195,7 @@ void llvm::GetReturnInfo(Type* ReturnType, AttributeSet attr,
       Flags.setZExt();
 
     for (unsigned i = 0; i < NumParts; ++i)
-      Outs.push_back(ISD::OutputArg(Flags, PartVT, /*isFixed=*/true, 0, 0));
+      Outs.push_back(ISD::OutputArg(Flags, PartVT, VT, /*isFixed=*/true, 0, 0));
   }
 }
 
-- 
1.7.11.4