Several changes to Mips backend, experimental fp support being the most
important.
- Cleanup in the Subtarget info with addition of new features, not all support
  yet, but they allow the future inclusion of features easier. Among new features,
  we have : Arch family info (mips1, mips2, ...), ABI info (o32, eabi), 64-bit
  integer
  and float registers, allegrex vector FPU (VFPU), single float only support.
- TargetMachine now detects allegrex core.
- Added allegrex (Mips32r2) sext_inreg instructions.
- *Added Float Point Instructions*, handling single float only, and
  aliased accesses for 32-bit FPUs.
- Some cleanup in FP instruction formats and FP register classes.
- Calling conventions improved to support mips 32-bit EABI.
- Added Asm Printer support for fp cond codes.
- Added support for sret copy to a return register.
- EABI support added into LowerCALL and FORMAL_ARGS.
- MipsFunctionInfo now keeps a virtual register per function to track the
  sret on function entry until function ret.
- MipsInstrInfo FP support into methods (isMoveInstr, isLoadFromStackSlot, ...),
  FP cond codes mapping and initial FP Branch Analysis.
- Two new Mips SDNode to handle fp branch and compare instructions : FPBrcond,
  FPCmp
- MipsTargetLowering : handling different FP classes, Allegrex support, sret
  return copy, no homing location within EABI, non 32-bit stack objects
  arguments, and asm constraint for float.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53146 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsSubtarget.h b/lib/Target/Mips/MipsSubtarget.h
index f106823..5300a81 100644
--- a/lib/Target/Mips/MipsSubtarget.h
+++ b/lib/Target/Mips/MipsSubtarget.h
@@ -26,11 +26,48 @@
 
 protected:
 
-  bool IsMipsIII;
+  enum MipsArchEnum {
+    Mips1, Mips2, Mips3, Mips4, Mips32, Mips32r2
+  };
+
+  enum MipsABIEnum {
+    O32, EABI
+  }; 
+  
+  // Mips architecture version 
+  MipsArchEnum MipsArchVersion;
+
+  // Mips supported ABIs 
+  MipsABIEnum MipsABI;
+
+  // IsLittle - The target is Little Endian
   bool IsLittle;
+
+  // IsSingleFloat - The target only supports single precision float
+  // point operations. This enable the target to use all 32 32-bit
+  // float point registers instead of only using even ones.
+  bool IsSingleFloat;
+
+  // IsFP64bit - The target processor has 64-bit float point registers.
+  bool IsFP64bit;
+
+  // IsFP64bit - General-purpose registers are 64 bits wide
+  bool IsGP64bit;
+
+  // HasAllegrexVFPU - Allegrex processor has a vector float point unit.
+  bool HasAllegrexVFPU;
+
+  // IsAllegrex - The target processor is a Allegrex core.
+  bool IsAllegrex;
+
   InstrItineraryData InstrItins;
 
 public:
+
+  /// Only O32 and EABI supported right now.
+  bool isABI_EABI() const { return MipsABI == EABI; }
+  bool isABI_O32() const { return MipsABI == O32; }
+
   /// This constructor initializes the data members to match that
   /// of the specified module.
   MipsSubtarget(const TargetMachine &TM, const Module &M, 
@@ -40,12 +77,17 @@
   /// subtarget options.  Definition of function is auto generated by tblgen.
   void ParseSubtargetFeatures(const std::string &FS, const std::string &CPU);
 
-  /// isMipsIII - Return true if the selected CPU supports MipsIII ISA
-  /// support. 
-  bool isMipsIII() const { return IsMipsIII; }
+  bool hasMips2Ops() const { return MipsArchVersion >= Mips2; }
 
-  /// isMipsIII - Return true if the target is little endian. 
   bool isLittle() const { return IsLittle; }
+  bool isFP64bit() const { return IsFP64bit; };
+  bool isGP64bit() const { return IsGP64bit; };
+  bool isGP32bit() const { return !IsGP64bit; };
+  bool isSingleFloat() const { return IsSingleFloat; };
+  bool isNotSingleFloat() const { return !IsSingleFloat; };
+  bool hasAllegrexVFPU() const { return HasAllegrexVFPU; };
+  bool isAllegrex() const { return IsAllegrex; };
+
 };
 } // End llvm namespace