Recommit "[mips] [IAS] Add support for BNE and BEQ with an immediate operand." (r239396).

Apparently, Arcanist didn't include some of my local changes in my previous
commit attempt.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239523 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/Mips/AsmParser/MipsAsmParser.cpp

@@ -208,6 +208,9 @@ class MipsAsmParser : public MCTargetAsmParser {
   bool expandLoadStoreMultiple(MCInst &Inst, SMLoc IDLoc,
                                SmallVectorImpl<MCInst> &Instructions);
 
+  bool expandBranchImm(MCInst &Inst, SMLoc IDLoc,
+                       SmallVectorImpl<MCInst> &Instructions);
+
   void createNop(bool hasShortDelaySlot, SMLoc IDLoc,
                  SmallVectorImpl<MCInst> &Instructions);
 
@@ -1619,6 +1622,8 @@ bool MipsAsmParser::needsExpansion(MCInst &Inst) {
   case Mips::SWM_MM:
   case Mips::JalOneReg:
   case Mips::JalTwoReg:
+  case Mips::BneImm:
+  case Mips::BeqImm:
     return true;
   default:
     return false;
@@ -1645,6 +1650,9 @@ bool MipsAsmParser::expandInstruction(MCInst &Inst, SMLoc IDLoc,
   case Mips::JalOneReg:
   case Mips::JalTwoReg:
     return expandJalWithRegs(Inst, IDLoc, Instructions);
+  case Mips::BneImm:
+  case Mips::BeqImm:
+    return expandBranchImm(Inst, IDLoc, Instructions);
   }
 }
 
@@ -2035,6 +2043,59 @@ bool MipsAsmParser::expandUncondBranchMMPseudo(
   return false;
 }
 
+bool MipsAsmParser::expandBranchImm(MCInst &Inst, SMLoc IDLoc,
+                                    SmallVectorImpl<MCInst> &Instructions) {
+  const MCOperand &DstRegOp = Inst.getOperand(0);
+  assert(DstRegOp.isReg() && "expected register operand kind");
+
+  const MCOperand &ImmOp = Inst.getOperand(1);
+  assert(ImmOp.isImm() && "expected immediate operand kind");
+
+  const MCOperand &MemOffsetOp = Inst.getOperand(2);
+  assert(MemOffsetOp.isImm() && "expected immediate operand kind");
+
+  unsigned OpCode = 0;
+  switch(Inst.getOpcode()) {
+    case Mips::BneImm:
+      OpCode = Mips::BNE;
+      break;
+    case Mips::BeqImm:
+      OpCode = Mips::BEQ;
+      break;
+    default:
+      llvm_unreachable("Unknown immediate branch pseudo-instruction.");
+      break;
+  }
+
+  int64_t ImmValue = ImmOp.getImm();
+  if (ImmValue == 0) {
+    MCInst BranchInst;
+    BranchInst.setOpcode(OpCode);
+    BranchInst.addOperand(DstRegOp);
+    BranchInst.addOperand(MCOperand::createReg(Mips::ZERO));
+    BranchInst.addOperand(MemOffsetOp);
+    Instructions.push_back(BranchInst);
+  } else {
+    warnIfNoMacro(IDLoc);
+
+    unsigned ATReg = getATReg(IDLoc);
+    if (!ATReg)
+      return true;
+
+    if (loadImmediate(ImmValue, ATReg, Mips::NoRegister, !isGP64bit(), IDLoc,
+                      Instructions))
+      return true;
+
+    MCInst BranchInst;
+    BranchInst.setOpcode(OpCode);
+    BranchInst.addOperand(DstRegOp);
+    BranchInst.addOperand(MCOperand::createReg(ATReg));
+    BranchInst.addOperand(MemOffsetOp);
+    Instructions.push_back(BranchInst);
+  }
+  return false;
+}
+
 void MipsAsmParser::expandMemInst(MCInst &Inst, SMLoc IDLoc,
                                   SmallVectorImpl<MCInst> &Instructions,
                                   bool isLoad, bool isImmOpnd) {

lib/Target/Mips/Mips64InstrInfo.td

@@ -27,8 +27,6 @@ def uimm16_64      : Operand<i64> {
 // Signed Operand
 def simm10_64 : Operand<i64>;
 
-def imm64: Operand<i64>;
-
 // Transformation Function - get Imm - 32.
 def Subtract32 : SDNodeXForm<imm, [{
   return getImm(N, (unsigned)N->getZExtValue() - 32);

lib/Target/Mips/MipsInstrInfo.td

@@ -358,6 +358,8 @@ def calltarget  : Operand<iPTR> {
   let ParserMatchClass = MipsJumpTargetAsmOperand;
 }
 
+def imm64: Operand<i64>;
+
 def simm9 : Operand<i32>;
 def simm10 : Operand<i32>;
 def simm11 : Operand<i32>;
@@ -1682,6 +1684,15 @@ def JalTwoReg : MipsAsmPseudoInst<(outs GPR32Opnd:$rd), (ins GPR32Opnd:$rs),
 def JalOneReg : MipsAsmPseudoInst<(outs), (ins GPR32Opnd:$rs),
                       "jal\t$rs"> ;
 
+let hasDelaySlot = 1 in {
+def BneImm : MipsAsmPseudoInst<(outs GPR32Opnd:$rt),
+                               (ins imm64:$imm64, brtarget:$offset),
+                               "bne\t$rt, $imm64, $offset">;
+def BeqImm : MipsAsmPseudoInst<(outs GPR32Opnd:$rt),
+                               (ins imm64:$imm64, brtarget:$offset),
+                               "beq\t$rt, $imm64, $offset">;
+}
+
 //===----------------------------------------------------------------------===//
 //  Arbitrary patterns that map to one or more instructions
 //===----------------------------------------------------------------------===//