Expand the sel pseudo/macro. This generates basic blocks where previously

there were inline br .+4 instructions. Soon everything can enjoy the
full instruction scheduling experience.

llvm-svn: 175718

lib/Target/Mips/Mips16InstrInfo.td

@@ -76,6 +76,10 @@ class F2RI16_ins<bits<5> _op, string asmstr,
   let Constraints = "$rx_ = $rx";
 }
 
+class FRI16_B_ins<bits<5> _op, string asmstr,
+                  InstrItinClass itin>:
+  FRI16<_op, (outs), (ins  CPU16Regs:$rx, brtarget:$imm),
+        !strconcat(asmstr, "\t$rx, $imm  # 16 bit inst"), [], itin>;
 //
 // Compare a register and immediate and place result in CC
 // Implicit use of T8
@@ -362,6 +366,7 @@ class Sel<string op>:
                !strconcat(op, "\t$rt, .+4\n\t\n\tmove $rd, $rs"), []> {
   //let isCodeGenOnly=1;
   let Constraints = "$rd = $rd_";
+  let usesCustomInserter = 1;
 }
 
 //
@@ -518,6 +523,14 @@ def AdduRxRyRz16: FRRR16_ins<01, "addu", IIAlu>, ArithLogic16Defs<1>;
 def AndRxRxRy16: FRxRxRy16_ins<0b01100, "and", IIAlu>, ArithLogic16Defs<1>;
 
 
+//
+// Format: BEQZ rx, offset MIPS16e
+// Purpose: Branch on Equal to Zero
+// To test a GPR then do a PC-relative conditional branch.
+//
+def BeqzRxImm16: FRI16_B_ins<0b00100, "beqz", IIAlu>, cbranch16;
+
+
 //
 // Format: BEQZ rx, offset MIPS16e
 // Purpose: Branch on Equal to Zero (Extended)
@@ -531,6 +544,13 @@ def BeqzRxImmX16: FEXT_RI16_B_ins<0b00100, "beqz", IIAlu>, cbranch16;
 //
 def BimmX16: FEXT_I16_ins<0b00010, "b", IIAlu>, branch16;
 
+//
+// Format: BNEZ rx, offset MIPS16e
+// Purpose: Branch on Not Equal to Zero
+// To test a GPR then do a PC-relative conditional branch.
+//
+def BnezRxImm16: FRI16_B_ins<0b00101, "bnez", IIAlu>, cbranch16;
+
 //
 // Format: BNEZ rx, offset MIPS16e
 // Purpose: Branch on Not Equal to Zero (Extended)

lib/Target/Mips/MipsISelLowering.cpp

@@ -55,6 +55,12 @@ Mips16HardFloat("mips16-hard-float", cl::NotHidden,
                 cl::desc("MIPS: mips16 hard float enable."),
                 cl::init(false));
 
+static cl::opt<bool> DontExpandCondPseudos16(
+  "mips16-dont-expand-cond-pseudo",
+  cl::init(false),
+  cl::desc("Dont expand conditional move related "
+           "pseudos for Mips 16"),
+  cl::Hidden);
 
 
 static const uint16_t O32IntRegs[4] = {
@@ -1230,11 +1236,74 @@ MipsTargetLowering::EmitBPOSGE32(MachineInstr *MI, MachineBasicBlock *BB) const{
   return Sink;
 }
 
+MachineBasicBlock *MipsTargetLowering::EmitSel16(unsigned Opc, MachineInstr *MI,
+                             MachineBasicBlock *BB) const {
+  if (DontExpandCondPseudos16)
+    return BB;
+  const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
+  DebugLoc dl = MI->getDebugLoc();
+  // To "insert" a SELECT_CC instruction, we actually have to insert the
+  // diamond control-flow pattern.  The incoming instruction knows the
+  // destination vreg to set, the condition code register to branch on, the
+  // true/false values to select between, and a branch opcode to use.
+  const BasicBlock *LLVM_BB = BB->getBasicBlock();
+  MachineFunction::iterator It = BB;
+  ++It;
+
+  //  thisMBB:
+  //  ...
+  //   TrueVal = ...
+  //   setcc r1, r2, r3
+  //   bNE   r1, r0, copy1MBB
+  //   fallthrough --> copy0MBB
+  MachineBasicBlock *thisMBB  = BB;
+  MachineFunction *F = BB->getParent();
+  MachineBasicBlock *copy0MBB = F->CreateMachineBasicBlock(LLVM_BB);
+  MachineBasicBlock *sinkMBB  = F->CreateMachineBasicBlock(LLVM_BB);
+  F->insert(It, copy0MBB);
+  F->insert(It, sinkMBB);
+
+  // Transfer the remainder of BB and its successor edges to sinkMBB.
+  sinkMBB->splice(sinkMBB->begin(), BB,
+                  llvm::next(MachineBasicBlock::iterator(MI)),
+                  BB->end());
+  sinkMBB->transferSuccessorsAndUpdatePHIs(BB);
+
+  // Next, add the true and fallthrough blocks as its successors.
+  BB->addSuccessor(copy0MBB);
+  BB->addSuccessor(sinkMBB);
+
+  BuildMI(BB, dl, TII->get(Opc)).addReg(MI->getOperand(3).getReg())
+    .addMBB(sinkMBB);
+
+  //  copy0MBB:
+  //   %FalseValue = ...
+  //   # fallthrough to sinkMBB
+  BB = copy0MBB;
+
+  // Update machine-CFG edges
+  BB->addSuccessor(sinkMBB);
+
+  //  sinkMBB:
+  //   %Result = phi [ %TrueValue, thisMBB ], [ %FalseValue, copy0MBB ]
+  //  ...
+  BB = sinkMBB;
+
+  BuildMI(*BB, BB->begin(), dl,
+          TII->get(Mips::PHI), MI->getOperand(0).getReg())
+    .addReg(MI->getOperand(1).getReg()).addMBB(thisMBB)
+    .addReg(MI->getOperand(2).getReg()).addMBB(copy0MBB);
+
+  MI->eraseFromParent();   // The pseudo instruction is gone now.
+  return BB;
+}
+
 MachineBasicBlock *
 MipsTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
                                                 MachineBasicBlock *BB) const {
   switch (MI->getOpcode()) {
-  default: llvm_unreachable("Unexpected instr type to insert");
+  default:
+    llvm_unreachable("Unexpected instr type to insert");
   case Mips::ATOMIC_LOAD_ADD_I8:
   case Mips::ATOMIC_LOAD_ADD_I8_P8:
     return EmitAtomicBinaryPartword(MI, BB, 1, Mips::ADDu);
@@ -1340,6 +1409,10 @@ MipsTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
     return EmitAtomicCmpSwap(MI, BB, 8);
   case Mips::BPOSGE32_PSEUDO:
     return EmitBPOSGE32(MI, BB);
+  case Mips::SelBeqZ:
+    return EmitSel16(Mips::BeqzRxImm16, MI, BB);
+  case Mips::SelBneZ:
+    return EmitSel16(Mips::BnezRxImm16, MI, BB);
   }
 }
 

lib/Target/Mips/MipsISelLowering.h

@@ -404,6 +404,9 @@ namespace llvm {
                                   MachineBasicBlock *BB, unsigned Size) const;
     MachineBasicBlock *EmitAtomicCmpSwapPartword(MachineInstr *MI,
                                   MachineBasicBlock *BB, unsigned Size) const;
+    MachineBasicBlock *EmitSel16(unsigned Opc, MachineInstr *MI,
+                                 MachineBasicBlock *BB) const;
+
   };
 }
 

test/CodeGen/Mips/selpat.ll

@@ -67,7 +67,7 @@ entry:
   %2 = load i32* @f, align 4
   %cond = select i1 %cmp, i32 %1, i32 %2
   store i32 %cond, i32* @z1, align 4
-; 16:	beqz	${{[0-9]+}}, .+4
+; 16:	beqz	${{[0-9]+}}, $BB{{[0-9]+}}_{{[0-9]}}
 ; 16: 	move    ${{[0-9]+}}, ${{[0-9]+}}
   %3 = load i32* @b, align 4
   %cmp1 = icmp eq i32 %3, 0
@@ -238,7 +238,7 @@ entry:
   %2 = load i32* @t, align 4
   %cond = select i1 %cmp, i32 %1, i32 %2
   store i32 %cond, i32* @z1, align 4
-; 16:	bnez	${{[0-9]+}}, .+4
+; 16:	bnez	${{[0-9]+}}, $BB{{[0-9]+}}_{{[0-9]}}
 ; 16: 	move    ${{[0-9]+}}, ${{[0-9]+}}
   %3 = load i32* @b, align 4
   %cmp1 = icmp ne i32 %3, 0
@@ -260,7 +260,7 @@ entry:
   %2 = load i32* @t, align 4
   %cond = select i1 %tobool, i32 %1, i32 %2
   store i32 %cond, i32* @z1, align 4
-; 16:	bnez	${{[0-9]+}}, .+4
+; 16:	bnez	${{[0-9]+}}, $BB{{[0-9]+}}_{{[0-9]}}
 ; 16: 	move    ${{[0-9]+}}, ${{[0-9]+}}
   %3 = load i32* @b, align 4
   %tobool1 = icmp ne i32 %3, 0