Teach CodeGen's version of computeMaskedBits to understand the range metadata.

This is the CodeGen equivalent of r153747. I tested that there is not noticeable
performance difference with any combination of -O0/-O2 /-g when compiling
gcc as a single compilation unit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153817 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/ValueTracking.h

@@ -24,7 +24,8 @@ namespace llvm {
   class APInt;
   class TargetData;
   class StringRef;
-  
+  class MDNode;
+
   /// ComputeMaskedBits - Determine which of the bits specified in Mask are
   /// known to be either zero or one and return them in the KnownZero/KnownOne
   /// bit sets.  This code only analyzes bits in Mask, in order to short-circuit
@@ -38,7 +39,9 @@ namespace llvm {
   void ComputeMaskedBits(Value *V, const APInt &Mask, APInt &KnownZero,
                          APInt &KnownOne, const TargetData *TD = 0,
                          unsigned Depth = 0);
-  
+  void computeMaskedBitsLoad(const MDNode &Ranges, const APInt &Mask,
+                             APInt &KnownZero);
+
   /// ComputeSignBit - Determine whether the sign bit is known to be zero or
   /// one.  Convenience wrapper around ComputeMaskedBits.
   void ComputeSignBit(Value *V, bool &KnownZero, bool &KnownOne,

include/llvm/CodeGen/MachineFunction.h

@@ -380,7 +380,8 @@ public:
   MachineMemOperand *getMachineMemOperand(MachinePointerInfo PtrInfo,
                                           unsigned f, uint64_t s,
                                           unsigned base_alignment,
-                                          const MDNode *TBAAInfo = 0);
+                                          const MDNode *TBAAInfo = 0,
+                                          const MDNode *Ranges = 0);
   
   /// getMachineMemOperand - Allocate a new MachineMemOperand by copying
   /// an existing one, adjusting by an offset and using the given size.

include/llvm/CodeGen/MachineMemOperand.h

@@ -84,6 +84,7 @@ class MachineMemOperand {
   uint64_t Size;
   unsigned Flags;
   const MDNode *TBAAInfo;
+  const MDNode *Ranges;
 
 public:
   /// Flags values. These may be or'd together.
@@ -105,7 +106,8 @@ public:
   /// MachineMemOperand - Construct an MachineMemOperand object with the
   /// specified PtrInfo, flags, size, and base alignment.
   MachineMemOperand(MachinePointerInfo PtrInfo, unsigned flags, uint64_t s,
-                    unsigned base_alignment, const MDNode *TBAAInfo = 0);
+                    unsigned base_alignment, const MDNode *TBAAInfo = 0,
+                    const MDNode *Ranges = 0);
 
   const MachinePointerInfo &getPointerInfo() const { return PtrInfo; }
   
@@ -140,6 +142,9 @@ public:
   /// getTBAAInfo - Return the TBAA tag for the memory reference.
   const MDNode *getTBAAInfo() const { return TBAAInfo; }
 
+  /// getRanges - Return the range tag for the memory reference.
+  const MDNode *getRanges() const { return Ranges; }
+
   bool isLoad() const { return Flags & MOLoad; }
   bool isStore() const { return Flags & MOStore; }
   bool isVolatile() const { return Flags & MOVolatile; }

include/llvm/CodeGen/SelectionDAG.h

@@ -654,7 +654,7 @@ public:
   SDValue getLoad(EVT VT, DebugLoc dl, SDValue Chain, SDValue Ptr,
                   MachinePointerInfo PtrInfo, bool isVolatile,
                   bool isNonTemporal, bool isInvariant, unsigned Alignment,
-                  const MDNode *TBAAInfo = 0);
+                  const MDNode *TBAAInfo = 0, const MDNode *Ranges = 0);
   SDValue getExtLoad(ISD::LoadExtType ExtType, DebugLoc dl, EVT VT,
                      SDValue Chain, SDValue Ptr, MachinePointerInfo PtrInfo,
                      EVT MemVT, bool isVolatile,
@@ -667,7 +667,8 @@ public:
                   SDValue Chain, SDValue Ptr, SDValue Offset,
                   MachinePointerInfo PtrInfo, EVT MemVT,
                   bool isVolatile, bool isNonTemporal, bool isInvariant,
-                  unsigned Alignment, const MDNode *TBAAInfo = 0);
+                  unsigned Alignment, const MDNode *TBAAInfo = 0,
+                  const MDNode *Ranges = 0);
   SDValue getLoad(ISD::MemIndexedMode AM, ISD::LoadExtType ExtType,
                   EVT VT, DebugLoc dl,
                   SDValue Chain, SDValue Ptr, SDValue Offset,

include/llvm/CodeGen/SelectionDAGNodes.h

@@ -933,6 +933,9 @@ public:
   /// Returns the TBAAInfo that describes the dereference.
   const MDNode *getTBAAInfo() const { return MMO->getTBAAInfo(); }
 
+  /// Returns the Ranges that describes the dereference.
+  const MDNode *getRanges() const { return MMO->getRanges(); }
+
   /// getMemoryVT - Return the type of the in-memory value.
   EVT getMemoryVT() const { return MemoryVT; }