This patch adds the register class for MIPS16 as well as the ability for

llc to recognize MIPS16 as a MIPS ASE extension. -mips16 will mean the
mips16 ASE for mips32 by default.

As part of fixing of adding this we discovered some small changes that
need to be made to MipsInstrInfo::storeRegToStackSLot and
MipsInstrInfo::loadRegFromStackSlot. We were using some "==" equality tests
where in fact we should have been using Mips::<regclas>.hasSubClassEQ instead,
per suggestion of Jakob Stoklund Olesen.

Patch by Reed Kotler.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156958 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 26 insertions, 11 deletions

diff --git a/lib/Target/Mips/Mips.td b/lib/Target/Mips/Mips.td
index cbebe84a18..8548ae0b8b 100644
--- a/lib/Target/Mips/Mips.td
+++ b/lib/Target/Mips/Mips.td
@@ -72,6 +72,9 @@ def FeatureMips64r2    : SubtargetFeature<"mips64r2", "MipsArchVersion",
                                 "Mips64r2", "Mips64r2 ISA Support",
                                 [FeatureMips64, FeatureMips32r2]>;
 
+def FeatureMips16  : SubtargetFeature<"mips16", "InMips16Mode", "true",
+                                      "Mips16 mode">;
+
 //===----------------------------------------------------------------------===//
 // Mips processors supported.
 //===----------------------------------------------------------------------===//
@@ -83,6 +86,7 @@ def : Proc<"mips32", [FeatureMips32]>;
 def : Proc<"mips32r2", [FeatureMips32r2]>;
 def : Proc<"mips64", [FeatureMips64]>;
 def : Proc<"mips64r2", [FeatureMips64r2]>;
+def : Proc<"mips16", [FeatureMips16]>;
 
 def MipsAsmWriter : AsmWriter {
   string AsmWriterClassName  = "InstPrinter";
diff --git a/lib/Target/Mips/MipsInstrInfo.cpp b/lib/Target/Mips/MipsInstrInfo.cpp
index 7578b17492..f5e2d3024e 100644
--- a/lib/Target/Mips/MipsInstrInfo.cpp
+++ b/lib/Target/Mips/MipsInstrInfo.cpp
@@ -189,15 +189,15 @@ storeRegToStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
 
   unsigned Opc = 0;
 
-  if (RC == &Mips::CPURegsRegClass)
+  if (Mips::CPURegsRegClass.hasSubClassEq(RC))
     Opc = IsN64 ? Mips::SW_P8 : Mips::SW;
-  else if (RC == &Mips::CPU64RegsRegClass)
+  else if (Mips::CPU64RegsRegClass.hasSubClassEq(RC))
     Opc = IsN64 ? Mips::SD_P8 : Mips::SD;
-  else if (RC == &Mips::FGR32RegClass)
+  else if (Mips::FGR32RegClass.hasSubClassEq(RC))
     Opc = IsN64 ? Mips::SWC1_P8 : Mips::SWC1;
-  else if (RC == &Mips::AFGR64RegClass)
+  else if (Mips::AFGR64RegClass.hasSubClassEq(RC))
     Opc = Mips::SDC1;
-  else if (RC == &Mips::FGR64RegClass)
+  else if (Mips::FGR64RegClass.hasSubClassEq(RC))
     Opc = IsN64 ? Mips::SDC164_P8 : Mips::SDC164;
 
   assert(Opc && "Register class not handled!");
@@ -216,15 +216,15 @@ loadRegFromStackSlot(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
   MachineMemOperand *MMO = GetMemOperand(MBB, FI, MachineMemOperand::MOLoad);
   unsigned Opc = 0;
 
-  if (RC == &Mips::CPURegsRegClass)
+  if (Mips::CPURegsRegClass.hasSubClassEq(RC))
     Opc = IsN64 ? Mips::LW_P8 : Mips::LW;
-  else if (RC == &Mips::CPU64RegsRegClass)
+  else if (Mips::CPU64RegsRegClass.hasSubClassEq(RC))
     Opc = IsN64 ? Mips::LD_P8 : Mips::LD;
-  else if (RC == &Mips::FGR32RegClass)
+  else if (Mips::FGR32RegClass.hasSubClassEq(RC))
     Opc = IsN64 ? Mips::LWC1_P8 : Mips::LWC1;
-  else if (RC == &Mips::AFGR64RegClass)
+  else if (Mips::AFGR64RegClass.hasSubClassEq(RC))
     Opc = Mips::LDC1;
-  else if (RC == &Mips::FGR64RegClass)
+  else if (Mips::FGR64RegClass.hasSubClassEq(RC))
     Opc = IsN64 ? Mips::LDC164_P8 : Mips::LDC164;
 
   assert(Opc && "Register class not handled!");
diff --git a/lib/Target/Mips/MipsRegisterInfo.td b/lib/Target/Mips/MipsRegisterInfo.td
index f7cc1f65ba..8a13bd13ea 100644
--- a/lib/Target/Mips/MipsRegisterInfo.td
+++ b/lib/Target/Mips/MipsRegisterInfo.td
@@ -265,6 +265,13 @@ def CPU64Regs : RegisterClass<"Mips", [i64], 64, (add
   // Reserved
   ZERO_64, AT_64, K0_64, K1_64, GP_64, SP_64, FP_64, RA_64)>;
 
+def CPU16Regs : RegisterClass<"Mips", [i32], 32, (add
+  // Return Values and Arguments
+  V0, V1, A0, A1, A2, A3,
+  // Callee save
+  S0, S1)>;
+
+
 // 64bit fp:
 // * FGR64  - 32 64-bit registers
 // * AFGR64 - 16 32-bit even registers (32-bit FP Mode)
diff --git a/lib/Target/Mips/MipsSubtarget.cpp b/lib/Target/Mips/MipsSubtarget.cpp
index 44522688d4..f072802db6 100644
--- a/lib/Target/Mips/MipsSubtarget.cpp
+++ b/lib/Target/Mips/MipsSubtarget.cpp
@@ -30,7 +30,7 @@ MipsSubtarget::MipsSubtarget(const std::string &TT, const std::string &CPU,
   MipsArchVersion(Mips32), MipsABI(UnknownABI), IsLittle(little),
   IsSingleFloat(false), IsFP64bit(false), IsGP64bit(false), HasVFPU(false),
   IsLinux(true), HasSEInReg(false), HasCondMov(false), HasMulDivAdd(false),
-  HasMinMax(false), HasSwap(false), HasBitCount(false)
+  HasMinMax(false), HasSwap(false), HasBitCount(false), InMips16Mode(false)
 {
   std::string CPUName = CPU;
   if (CPUName.empty())
diff --git a/lib/Target/Mips/MipsSubtarget.h b/lib/Target/Mips/MipsSubtarget.h
index 7faf77baa6..4c8bdde904 100644
--- a/lib/Target/Mips/MipsSubtarget.h
+++ b/lib/Target/Mips/MipsSubtarget.h
@@ -86,6 +86,9 @@ protected:
   // HasBitCount - Count leading '1' and '0' bits.
   bool HasBitCount;
 
+  // InMips16 -- can process Mips16 instructions
+  bool InMips16Mode;
+
   InstrItineraryData InstrItins;
 
 public:
@@ -124,6 +127,7 @@ public:
   bool isSingleFloat() const { return IsSingleFloat; }
   bool isNotSingleFloat() const { return !IsSingleFloat; }
   bool hasVFPU() const { return HasVFPU; }
+  bool inMips16Mode() const { return InMips16Mode; }
   bool isLinux() const { return IsLinux; }
 
   /// Features related to the presence of specific instructions.