Add CopyCost to TargetRegisterClass. This specifies the cost of copying a value

between two registers in the specific class.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42123 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/MRegisterInfo.h

@@ -70,6 +70,7 @@ private:
   const sc_iterator SubRegClasses;
   const sc_iterator SuperRegClasses;
   const unsigned RegSize, Alignment;    // Size & Alignment of register in bytes
+  const int CopyCost;
   const iterator RegsBegin, RegsEnd;
 public:
   TargetRegisterClass(unsigned id,
@@ -78,10 +79,11 @@ public:
                       const TargetRegisterClass * const *supcs,
                       const TargetRegisterClass * const *subregcs,
                       const TargetRegisterClass * const *superregcs,
-                      unsigned RS, unsigned Al, iterator RB, iterator RE)
+                      unsigned RS, unsigned Al, int CC,
+                      iterator RB, iterator RE)
     : ID(id), VTs(vts), SubClasses(subcs), SuperClasses(supcs),
     SubRegClasses(subregcs), SuperRegClasses(superregcs),
-    RegSize(RS), Alignment(Al), RegsBegin(RB), RegsEnd(RE) {}
+    RegSize(RS), Alignment(Al), CopyCost(CC), RegsBegin(RB), RegsEnd(RE) {}
   virtual ~TargetRegisterClass() {}     // Allow subclasses
   
   /// getID() - Return the register class ID number.
@@ -258,6 +260,10 @@ public:
   /// getAlignment - Return the minimum required alignment for a register of
   /// this class.
   unsigned getAlignment() const { return Alignment; }
+
+  /// getCopyCost - Return the cost of copying a value between two registers in
+  /// this class.
+  int getCopyCost() const { return CopyCost; }
 };
 
 

lib/Target/Target.td

@@ -104,6 +104,12 @@ class RegisterClass<string namespace, list<ValueType> regTypes, int alignment,
   //
   int Alignment = alignment;
 
+  // CopyCost - This value is used to specify the cost of copying a value
+  // between two registers in this register class. The default value is one
+  // meaning it takes a single instruction to perform the copying. A negative
+  // value means copying is extremely expensive or impossible.
+  int CopyCost = 1;
+
   // MemberList - Specify which registers are in this class.  If the
   // allocation_order_* method are not specified, this also defines the order of
   // allocation used by the register allocator.

utils/TableGen/CodeGenRegisters.h

@@ -38,6 +38,7 @@ namespace llvm {
     std::vector<MVT::ValueType> VTs;
     unsigned SpillSize;
     unsigned SpillAlignment;
+    int CopyCost;
     std::vector<Record*> SubRegClasses;
     std::string MethodProtos, MethodBodies;
 

utils/TableGen/CodeGenTarget.cpp

@@ -221,6 +221,7 @@ CodeGenRegisterClass::CodeGenRegisterClass(Record *R) : TheDef(R) {
   Namespace = R->getValueAsString("Namespace");
   SpillSize = Size ? Size : MVT::getSizeInBits(VTs[0]);
   SpillAlignment = R->getValueAsInt("Alignment");
+  CopyCost = R->getValueAsInt("CopyCost");
   MethodBodies = R->getValueAsCode("MethodBodies");
   MethodProtos = R->getValueAsCode("MethodProtos");
 }

utils/TableGen/RegisterInfoEmitter.cpp

@@ -384,8 +384,10 @@ void RegisterInfoEmitter::run(std::ostream &OS) {
          << RC.getName() + "SubRegClasses" << ", "
          << RC.getName() + "SuperRegClasses" << ", "
          << RC.SpillSize/8 << ", "
-         << RC.SpillAlignment/8 << ", " << RC.getName() << ", "
-         << RC.getName() << " + " << RC.Elements.size() << ") {}\n";
+         << RC.SpillAlignment/8 << ", "
+         << RC.CopyCost << ", "
+         << RC.getName() << ", " << RC.getName() << " + " << RC.Elements.size()
+         << ") {}\n";
     }
   
     OS << "}\n";