Use an IndexedMap for LiveVariables::VirtRegInfo.

Provide MRI::getNumVirtRegs() and TRI::index2VirtReg() functions to allow
iteration over virtual registers without depending on the representation of
virtual register numbers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123098 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 15 insertions, 4 deletions

diff --git a/include/llvm/CodeGen/LiveVariables.h b/include/llvm/CodeGen/LiveVariables.h
index ea32efa..f9b81b1 100644
--- a/include/llvm/CodeGen/LiveVariables.h
+++ b/include/llvm/CodeGen/LiveVariables.h
@@ -32,8 +32,10 @@
 #include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/IndexedMap.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/SparseBitVector.h"
@@ -121,10 +123,9 @@ public:
 
 private:
   /// VirtRegInfo - This list is a mapping from virtual register number to
-  /// variable information.  FirstVirtualRegister is subtracted from the virtual
-  /// register number before indexing into this list.
+  /// variable information.
   ///
-  std::vector<VarInfo> VirtRegInfo;
+  IndexedMap<VarInfo, VirtReg2IndexFunctor> VirtRegInfo;
 
   /// PHIJoins - list of virtual registers that are PHI joins. These registers
   /// may have multiple definitions, and they require special handling when
diff --git a/include/llvm/CodeGen/MachineRegisterInfo.h b/include/llvm/CodeGen/MachineRegisterInfo.h
index ddba61b..20f8bc8 100644
--- a/include/llvm/CodeGen/MachineRegisterInfo.h
+++ b/include/llvm/CodeGen/MachineRegisterInfo.h
@@ -216,10 +216,14 @@ public:
   ///
   unsigned createVirtualRegister(const TargetRegisterClass *RegClass);
 
+  /// getNumVirtRegs - Return the number of virtual registers created.
+  ///
+  unsigned getNumVirtRegs() const { return VRegInfo.size(); }
+
   /// getLastVirtReg - Return the highest currently assigned virtual register.
   ///
   unsigned getLastVirtReg() const {
-    return (unsigned)VRegInfo.size()+TargetRegisterInfo::FirstVirtualRegister-1;
+    return TargetRegisterInfo::index2VirtReg(getNumVirtRegs() - 1);
   }
 
   /// getRegClassVirtRegs - Return the list of virtual registers of the given
diff --git a/include/llvm/Target/TargetRegisterInfo.h b/include/llvm/Target/TargetRegisterInfo.h
index 05ccf04..d26c67b 100644
--- a/include/llvm/Target/TargetRegisterInfo.h
+++ b/include/llvm/Target/TargetRegisterInfo.h
@@ -321,6 +321,12 @@ public:
     return Reg >= FirstVirtualRegister;
   }
 
+  /// index2VirtReg - Convert a 0-based index to a virtual register number.
+  /// This is the inverse operation of VirtReg2IndexFunctor below.
+  static unsigned index2VirtReg(unsigned Index) {
+    return Index + FirstVirtualRegister;
+  }
+
   /// printReg - Print a virtual or physical register on OS.
   void printReg(unsigned Reg, raw_ostream &OS) const;