SDAGBuilder: Remove register sets that were never read and prune dead code surrounding it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151364 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 63 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index c7d676e..44de41f 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -5677,22 +5677,6 @@ public:
     : TargetLowering::AsmOperandInfo(info), CallOperand(0,0) {
   }
 
-  /// MarkAllocatedRegs - Once AssignedRegs is set, mark the assigned registers
-  /// busy in OutputRegs/InputRegs.
-  void MarkAllocatedRegs(bool isOutReg, bool isInReg,
-                         std::set<unsigned> &OutputRegs,
-                         std::set<unsigned> &InputRegs,
-                         const TargetRegisterInfo &TRI) const {
-    if (isOutReg) {
-      for (unsigned i = 0, e = AssignedRegs.Regs.size(); i != e; ++i)
-        MarkRegAndAliases(AssignedRegs.Regs[i], OutputRegs, TRI);
-    }
-    if (isInReg) {
-      for (unsigned i = 0, e = AssignedRegs.Regs.size(); i != e; ++i)
-        MarkRegAndAliases(AssignedRegs.Regs[i], InputRegs, TRI);
-    }
-  }
-
   /// getCallOperandValEVT - Return the EVT of the Value* that this operand
   /// corresponds to.  If there is no Value* for this operand, it returns
   /// MVT::Other.
@@ -5740,18 +5724,6 @@ public:
 
     return TLI.getValueType(OpTy, true);
   }
-
-private:
-  /// MarkRegAndAliases - Mark the specified register and all aliases in the
-  /// specified set.
-  static void MarkRegAndAliases(unsigned Reg, std::set<unsigned> &Regs,
-                                const TargetRegisterInfo &TRI) {
-    assert(TargetRegisterInfo::isPhysicalRegister(Reg) && "Isn't a physreg");
-    Regs.insert(Reg);
-    if (const unsigned *Aliases = TRI.getAliasSet(Reg))
-      for (; *Aliases; ++Aliases)
-        Regs.insert(*Aliases);
-  }
 };
 
 typedef SmallVector<SDISelAsmOperandInfo,16> SDISelAsmOperandInfoVector;
@@ -5765,39 +5737,13 @@ typedef SmallVector<SDISelAsmOperandInfo,16> SDISelAsmOperandInfoVector;
 /// allocation.  This produces generally horrible, but correct, code.
 ///
 ///   OpInfo describes the operand.
-///   Input and OutputRegs are the set of already allocated physical registers.
 ///
 static void GetRegistersForValue(SelectionDAG &DAG,
                                  const TargetLowering &TLI,
                                  DebugLoc DL,
-                                 SDISelAsmOperandInfo &OpInfo,
-                                 std::set<unsigned> &OutputRegs,
-                                 std::set<unsigned> &InputRegs) {
+                                 SDISelAsmOperandInfo &OpInfo) {
   LLVMContext &Context = *DAG.getContext();
 
-  // Compute whether this value requires an input register, an output register,
-  // or both.
-  bool isOutReg = false;
-  bool isInReg = false;
-  switch (OpInfo.Type) {
-  case InlineAsm::isOutput:
-    isOutReg = true;
-
-    // If there is an input constraint that matches this, we need to reserve
-    // the input register so no other inputs allocate to it.
-    isInReg = OpInfo.hasMatchingInput();
-    break;
-  case InlineAsm::isInput:
-    isInReg = true;
-    isOutReg = false;
-    break;
-  case InlineAsm::isClobber:
-    isOutReg = true;
-    isInReg = true;
-    break;
-  }
-
-
   MachineFunction &MF = DAG.getMachineFunction();
   SmallVector<unsigned, 4> Regs;
 
@@ -5871,8 +5817,6 @@ static void GetRegistersForValue(SelectionDAG &DAG,
     }
 
     OpInfo.AssignedRegs = RegsForValue(Regs, RegVT, ValueVT);
-    const TargetRegisterInfo *TRI = DAG.getTarget().getRegisterInfo();
-    OpInfo.MarkAllocatedRegs(isOutReg, isInReg, OutputRegs, InputRegs, *TRI);
     return;
   }
 
@@ -5903,8 +5847,6 @@ void SelectionDAGBuilder::visitInlineAsm(ImmutableCallSite CS) {
   /// ConstraintOperands - Information about all of the constraints.
   SDISelAsmOperandInfoVector ConstraintOperands;
 
-  std::set<unsigned> OutputRegs, InputRegs;
-
   TargetLowering::AsmOperandInfoVector
     TargetConstraints = TLI.ParseConstraints(CS);
 
@@ -6066,8 +6008,7 @@ void SelectionDAGBuilder::visitInlineAsm(ImmutableCallSite CS) {
     // If this constraint is for a specific register, allocate it before
     // anything else.
     if (OpInfo.ConstraintType == TargetLowering::C_Register)
-      GetRegistersForValue(DAG, TLI, getCurDebugLoc(), OpInfo, OutputRegs,
-                           InputRegs);
+      GetRegistersForValue(DAG, TLI, getCurDebugLoc(), OpInfo);
   }
 
   // Second pass - Loop over all of the operands, assigning virtual or physregs
@@ -6078,8 +6019,7 @@ void SelectionDAGBuilder::visitInlineAsm(ImmutableCallSite CS) {
     // C_Register operands have already been allocated, Other/Memory don't need
     // to be.
     if (OpInfo.ConstraintType == TargetLowering::C_RegisterClass)
-      GetRegistersForValue(DAG, TLI, getCurDebugLoc(), OpInfo, OutputRegs,
-                           InputRegs);
+      GetRegistersForValue(DAG, TLI, getCurDebugLoc(), OpInfo);
   }
 
   // AsmNodeOperands - The operands for the ISD::INLINEASM node.