fix most of remaining issues with large frames.

these patches are tested a lot by test-suite but
make check tests are forthcoming once the next
few patches that complete this are committed.
with the next few patches the pass rate for mips16 is
near 100%



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170656 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 197 insertions, 20 deletions

diff --git a/lib/Target/Mips/Mips16FrameLowering.cpp b/lib/Target/Mips/Mips16FrameLowering.cpp
index d17c1259e5..e0c51ed587 100644
--- a/lib/Target/Mips/Mips16FrameLowering.cpp
+++ b/lib/Target/Mips/Mips16FrameLowering.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "Mips16FrameLowering.h"
+#include "Mips16InstrInfo.h"
 #include "MCTargetDesc/MipsBaseInfo.h"
 #include "MipsInstrInfo.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
@@ -29,8 +30,8 @@ using namespace llvm;
 void Mips16FrameLowering::emitPrologue(MachineFunction &MF) const {
   MachineBasicBlock &MBB = MF.front();
   MachineFrameInfo *MFI = MF.getFrameInfo();
-  const MipsInstrInfo &TII =
-    *static_cast<const MipsInstrInfo*>(MF.getTarget().getInstrInfo());
+  const Mips16InstrInfo &TII =
+    *static_cast<const Mips16InstrInfo*>(MF.getTarget().getInstrInfo());
   MachineBasicBlock::iterator MBBI = MBB.begin();
   DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
   uint64_t StackSize = MFI->getStackSize();
@@ -39,8 +40,7 @@ void Mips16FrameLowering::emitPrologue(MachineFunction &MF) const {
   if (StackSize == 0 && !MFI->adjustsStack()) return;
 
   // Adjust stack.
-  if (isInt<16>(-StackSize))
-    BuildMI(MBB, MBBI, dl, TII.get(Mips::SaveRaF16)).addImm(StackSize);
+  TII.makeFrame(Mips::SP, StackSize, MBB, MBBI);
 
   if (hasFP(MF))
     BuildMI(MBB, MBBI, dl, TII.get(Mips::MoveR3216), Mips::S0)
@@ -52,8 +52,8 @@ void Mips16FrameLowering::emitEpilogue(MachineFunction &MF,
                                  MachineBasicBlock &MBB) const {
   MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
   MachineFrameInfo *MFI = MF.getFrameInfo();
-  const MipsInstrInfo &TII =
-    *static_cast<const MipsInstrInfo*>(MF.getTarget().getInstrInfo());
+  const Mips16InstrInfo &TII =
+    *static_cast<const Mips16InstrInfo*>(MF.getTarget().getInstrInfo());
   DebugLoc dl = MBBI->getDebugLoc();
   uint64_t StackSize = MFI->getStackSize();
 
@@ -65,9 +65,8 @@ void Mips16FrameLowering::emitEpilogue(MachineFunction &MF,
       .addReg(Mips::S0);
 
   // Adjust stack.
-  if (isInt<16>(StackSize))
-    // assumes stacksize multiple of 8
-    BuildMI(MBB, MBBI, dl, TII.get(Mips::RestoreRaF16)).addImm(StackSize);
+  // assumes stacksize multiple of 8
+  TII.restoreFrame(Mips::SP, StackSize, MBB, MBBI);
 }
 
 bool Mips16FrameLowering::
diff --git a/lib/Target/Mips/Mips16InstrInfo.cpp b/lib/Target/Mips/Mips16InstrInfo.cpp
index 10b696fe87..91b5ba0800 100644
--- a/lib/Target/Mips/Mips16InstrInfo.cpp
+++ b/lib/Target/Mips/Mips16InstrInfo.cpp
@@ -19,11 +19,19 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/TargetRegistry.h"
 
 using namespace llvm;
 
+static cl::opt<bool> NeverUseSaveRestore(
+  "mips16-never-use-save-restore",
+  cl::init(false),
+  cl::desc("For testing ability to adjust stack pointer without save/restore instruction"),
+  cl::Hidden);
+
+
 Mips16InstrInfo::Mips16InstrInfo(MipsTargetMachine &tm)
   : MipsInstrInfo(tm, Mips::BimmX16),
     RI(*tm.getSubtargetImpl(), *this) {}
@@ -160,20 +168,135 @@ unsigned Mips16InstrInfo::GetOppositeBranchOpc(unsigned Opc) const {
   return 0;
 }
 
+// Adjust SP by FrameSize bytes. Save RA, S0, S1
+void Mips16InstrInfo::makeFrame(unsigned SP, int64_t FrameSize, MachineBasicBlock &MBB,
+                    MachineBasicBlock::iterator I) const {
+  DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
+  if (!NeverUseSaveRestore) {
+    if (isUInt<11>(FrameSize))
+      BuildMI(MBB, I, DL, get(Mips::SaveRaF16)).addImm(FrameSize);
+    else {
+      int Base = 2040; // should create template function like isUInt that returns largest
+                       // possible n bit unsigned integer
+      int64_t Remainder = FrameSize - Base;
+      BuildMI(MBB, I, DL, get(Mips::SaveRaF16)). addImm(Base);
+      if (isInt<16>(-Remainder))
+        BuildMI(MBB, I, DL, get(Mips::AddiuSpImmX16)). addImm(-Remainder);
+      else
+        adjustStackPtrBig(SP, -Remainder, MBB, I, Mips::V0, Mips::V1);
+    }
+
+  }
+  else {
+    //
+    // sw ra, -4[sp]
+    // sw s1, -8[sp]
+    // sw s0, -12[sp]
+
+    MachineInstrBuilder MIB1 = BuildMI(MBB, I, DL, get(Mips::SwRxSpImmX16), Mips::RA);
+    MIB1.addReg(Mips::SP);
+    MIB1.addImm(-4);
+    MachineInstrBuilder MIB2 = BuildMI(MBB, I, DL, get(Mips::SwRxSpImmX16), Mips::S1);
+    MIB2.addReg(Mips::SP);
+    MIB2.addImm(-8);
+    MachineInstrBuilder MIB3 = BuildMI(MBB, I, DL, get(Mips::SwRxSpImmX16), Mips::S0);
+    MIB3.addReg(Mips::SP);
+    MIB3.addImm(-12);
+    adjustStackPtrBig(SP, -FrameSize, MBB, I, Mips::V0, Mips::V1);
+  }
+}
+
+// Adjust SP by FrameSize bytes. Restore RA, S0, S1
+void Mips16InstrInfo::restoreFrame(unsigned SP, int64_t FrameSize, MachineBasicBlock &MBB,
+                    MachineBasicBlock::iterator I) const {
+  DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
+  if (!NeverUseSaveRestore) {
+    if (isUInt<11>(FrameSize))
+      BuildMI(MBB, I, DL, get(Mips::RestoreRaF16)).addImm(FrameSize);
+    else {
+      int Base = 2040; // should create template function like isUInt that returns largest
+                       // possible n bit unsigned integer
+      int64_t Remainder = FrameSize - Base;
+      if (isInt<16>(Remainder))
+        BuildMI(MBB, I, DL, get(Mips::AddiuSpImmX16)). addImm(Remainder);
+      else
+        adjustStackPtrBig(SP, Remainder, MBB, I, Mips::A0, Mips::A1);
+      BuildMI(MBB, I, DL, get(Mips::RestoreRaF16)). addImm(Base);
+    }
+  }
+  else {
+    adjustStackPtrBig(SP, FrameSize, MBB, I, Mips::A0, Mips::A1);
+    // lw ra, -4[sp]
+    // lw s1, -8[sp]
+    // lw s0, -12[sp]
+    MachineInstrBuilder MIB1 = BuildMI(MBB, I, DL, get(Mips::LwRxSpImmX16), Mips::A0);
+    MIB1.addReg(Mips::SP);
+    MIB1.addImm(-4);
+    MachineInstrBuilder MIB0 = BuildMI(MBB, I, DL, get(Mips::Move32R16), Mips::RA);
+     MIB0.addReg(Mips::A0);
+    MachineInstrBuilder MIB2 = BuildMI(MBB, I, DL, get(Mips::LwRxSpImmX16), Mips::S1);
+    MIB2.addReg(Mips::SP);
+    MIB2.addImm(-8);
+    MachineInstrBuilder MIB3 = BuildMI(MBB, I, DL, get(Mips::LwRxSpImmX16), Mips::S0);
+    MIB3.addReg(Mips::SP);
+    MIB3.addImm(-12);
+  }
+
+}
+
+// Adjust SP by Amount bytes where bytes can be up to 32bit number.
+// This can only be called at times that we know that there is at least one free register.
+// This is clearly safe at prologue and epilogue.
+//
+void Mips16InstrInfo::adjustStackPtrBig(unsigned SP, int64_t Amount, MachineBasicBlock &MBB,
+                                        MachineBasicBlock::iterator I,
+                                        unsigned Reg1, unsigned Reg2) const {
+  DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
+//  MachineRegisterInfo &RegInfo = MBB.getParent()->getRegInfo();
+//  unsigned Reg1 = RegInfo.createVirtualRegister(&Mips::CPU16RegsRegClass);
+//  unsigned Reg2 = RegInfo.createVirtualRegister(&Mips::CPU16RegsRegClass);
+  //
+  // li reg1, constant
+  // move reg2, sp
+  // add reg1, reg1, reg2
+  // move sp, reg1
+  //
+  //
+  MachineInstrBuilder MIB1 = BuildMI(MBB, I, DL, get(Mips::LwConstant32), Reg1);
+  MIB1.addImm(Amount);
+  MachineInstrBuilder MIB2 = BuildMI(MBB, I, DL, get(Mips::MoveR3216), Reg2);
+  MIB2.addReg(Mips::SP, RegState::Kill);
+  MachineInstrBuilder MIB3 = BuildMI(MBB, I, DL, get(Mips::AdduRxRyRz16), Reg1);
+  MIB3.addReg(Reg1);
+  MIB3.addReg(Reg2, RegState::Kill);
+  MachineInstrBuilder MIB4 = BuildMI(MBB, I, DL, get(Mips::Move32R16), Mips::SP);
+  MIB4.addReg(Reg1, RegState::Kill);
+}
+
+void Mips16InstrInfo::adjustStackPtrBigUnrestricted(unsigned SP, int64_t Amount, MachineBasicBlock &MBB,
+                    MachineBasicBlock::iterator I) const {
+   assert(false && "adjust stack pointer amount exceeded");
+}
+
 /// Adjust SP by Amount bytes.
 void Mips16InstrInfo::adjustStackPtr(unsigned SP, int64_t Amount,
                                      MachineBasicBlock &MBB,
                                      MachineBasicBlock::iterator I) const {
   DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
-  if (isInt<16>(Amount)) {
-    if (Amount < 0)
-      BuildMI(MBB, I, DL, get(Mips::SaveDecSpF16)). addImm(-Amount);
-    else if (Amount > 0)
-      BuildMI(MBB, I, DL, get(Mips::RestoreIncSpF16)).addImm(Amount);
-  }
+  if (isInt<16>(Amount))  // need to change to addiu sp, ....and isInt<16>
+    BuildMI(MBB, I, DL, get(Mips::AddiuSpImmX16)). addImm(Amount);
   else
-    // not implemented for large values yet
-    assert(false && "adjust stack pointer amount exceeded");
+    adjustStackPtrBigUnrestricted(SP, Amount, MBB, I);
+}
+
+/// This function generates the sequence of instructions needed to get the
+/// result of adding register REG and immediate IMM.
+unsigned
+Mips16InstrInfo::loadImmediate(int64_t Imm, MachineBasicBlock &MBB,
+                               MachineBasicBlock::iterator II, DebugLoc DL,
+                               unsigned *NewImm) const {
+
+  return 0;
 }
 
 unsigned Mips16InstrInfo::GetAnalyzableBrOpc(unsigned Opc) const {
diff --git a/lib/Target/Mips/Mips16InstrInfo.h b/lib/Target/Mips/Mips16InstrInfo.h
index d6ef8d2bf1..16487e7937 100644
--- a/lib/Target/Mips/Mips16InstrInfo.h
+++ b/lib/Target/Mips/Mips16InstrInfo.h
@@ -64,15 +64,42 @@ public:
 
   virtual unsigned GetOppositeBranchOpc(unsigned Opc) const;
 
+  // Adjust SP by FrameSize bytes. Save RA, S0, S1
+  void makeFrame(unsigned SP, int64_t FrameSize, MachineBasicBlock &MBB,
+                      MachineBasicBlock::iterator I) const;
+
+  // Adjust SP by FrameSize bytes. Restore RA, S0, S1
+  void restoreFrame(unsigned SP, int64_t FrameSize, MachineBasicBlock &MBB,
+                      MachineBasicBlock::iterator I) const;
+
+
   /// Adjust SP by Amount bytes.
   void adjustStackPtr(unsigned SP, int64_t Amount, MachineBasicBlock &MBB,
                       MachineBasicBlock::iterator I) const;
 
+  /// Emit a series of instructions to load an immediate. If NewImm is a
+  /// non-NULL parameter, the last instruction is not emitted, but instead
+  /// its immediate operand is returned in NewImm.
+  unsigned loadImmediate(int64_t Imm, MachineBasicBlock &MBB,
+                         MachineBasicBlock::iterator II, DebugLoc DL,
+                         unsigned *NewImm) const;
+
 private:
   virtual unsigned GetAnalyzableBrOpc(unsigned Opc) const;
 
   void ExpandRetRA16(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
                    unsigned Opc) const;
+
+  // Adjust SP by Amount bytes where bytes can be up to 32bit number.
+  void adjustStackPtrBig(unsigned SP, int64_t Amount, MachineBasicBlock &MBB,
+                         MachineBasicBlock::iterator I,
+                         unsigned Reg1, unsigned Reg2) const;
+
+  // Adjust SP by Amount bytes where bytes can be up to 32bit number.
+  void adjustStackPtrBigUnrestricted(unsigned SP, int64_t Amount, MachineBasicBlock &MBB,
+                      MachineBasicBlock::iterator I) const;
+
+
 };
 
 }
diff --git a/lib/Target/Mips/Mips16InstrInfo.td b/lib/Target/Mips/Mips16InstrInfo.td
index ebbd21409d..e8e2f3ce41 100644
--- a/lib/Target/Mips/Mips16InstrInfo.td
+++ b/lib/Target/Mips/Mips16InstrInfo.td
@@ -57,13 +57,17 @@ class FEXT_I16_ins<bits<5> eop, string asmstr, InstrItinClass itin> :
 
 class FEXT_I816_ins_base<bits<3> _func, string asmstr,
                          string asmstr2, InstrItinClass itin>:
-  FEXT_I816<_func, (outs), (ins uimm16:$imm), !strconcat(asmstr, asmstr2),
+  FEXT_I816<_func, (outs), (ins simm16:$imm), !strconcat(asmstr, asmstr2),
             [], itin>;
 
 class FEXT_I816_ins<bits<3> _func, string asmstr,
                     InstrItinClass itin>:
   FEXT_I816_ins_base<_func, asmstr, "\t$imm", itin>;
 
+class FEXT_I816_SP_ins<bits<3> _func, string asmstr,
+                       InstrItinClass itin>:
+      FEXT_I816_ins_base<_func, asmstr, "\t$$sp, $imm", itin>;
+
 //
 // Assembler formats in alphabetical order.
 // Natural and pseudos are mixed together.
@@ -352,6 +356,18 @@ class SelT<bits<5> f1, string op1, bits<5> f2, string op2,
   let Constraints = "$rd = $rd_";
 }
 
+//
+// 32 bit constant
+//
+def imm32: Operand<i32>;
+
+def Constant32:
+  MipsPseudo16<(outs), (ins imm32:$imm), "\t.word $imm", []>;
+  
+def LwConstant32:
+  MipsPseudo16<(outs), (ins CPU16Regs:$rx, imm32:$imm),
+    "lw\t$rx, 1f\n\tb\t2f\n\t.align\t2\n1: \t.word\t$imm\n2:", []>;
+
 
 //
 // Some general instruction class info
@@ -404,6 +420,18 @@ def AddiuRxRyOffMemX16:
 // To add a constant to the program counter.
 //
 def AddiuRxPcImmX16: FEXT_RI16_PC_ins<0b00001, "addiu", IIAlu>;
+
+//
+// Format: ADDIU sp, immediate MIPS16e
+// Purpose: Add Immediate Unsigned Word (2-Operand, SP-Relative, Extended)
+// To add a constant to the stack pointer.
+//
+def AddiuSpImmX16
+  : FEXT_I816_SP_ins<0b011, "addiu", IIAlu> {
+  let Defs = [SP];
+  let Uses = [SP];
+}   
+
 //
 // Format: ADDU rz, rx, ry MIPS16e
 // Purpose: Add Unsigned Word (3-Operand)
diff --git a/test/CodeGen/Mips/alloca16.ll b/test/CodeGen/Mips/alloca16.ll
index 731edae43c..5ae9a84791 100644
--- a/test/CodeGen/Mips/alloca16.ll
+++ b/test/CodeGen/Mips/alloca16.ll
@@ -68,8 +68,8 @@ entry:
   %21 = load i32** %ip, align 4
   %arrayidx6 = getelementptr inbounds i32* %21, i32 %20
   %22 = load i32* %arrayidx6, align 4
-; 16: 	save	16
+; 16: 	addiu $sp, -16
   call void @temp(i32 %22)
-; 16: 	restore	16
+; 16: 	addiu $sp, 16
   ret void
 }