[mips][microMIPS] Implement BGEZALS and BLTZALS instructions

[jkolek]

Summary

Implement microMIPS branch instructions BGEZALS and BLTZALS with short delay slot.

[dsanders]

LGTM with a nit

lib/Target/Mips/MicroMipsInstrInfo.td

119 ↗

(On Diff #12761)

Nit: It's not very clear what the zero refers to in 'BranchZeroLinkMM'. Would 'BranchCompareToZeroLinkMM' be better?

[jkolek]

The class 'BranchZeroLinkMM' has been renamed to 'BranchCompareToZeroLinkMM'.

Closed by commit rL217678 (authored by zjovanovic).

llvm/trunk/lib/Target/Mips/AsmParser/MipsAsmParser.cpp

 static const MCInstrDesc &getInstDesc(unsigned Opcode) {
   return MipsInsts[Opcode];
 }
 
 static bool hasShortDelaySlot(unsigned Opcode) {
   switch (Opcode) {
     case Mips::JALS_MM:
     case Mips::JALRS_MM:
+    case Mips::BGEZALS_MM:
+    case Mips::BLTZALS_MM:
       return true;
     default:
       return false;
   }
 }
 
 bool MipsAsmParser::processInstruction(MCInst &Inst, SMLoc IDLoc,
                                        SmallVectorImpl<MCInst> &Instructions) {

llvm/trunk/lib/Target/Mips/MicroMipsInstrInfo.td

class JumpLinkMM<string opstr, DAGOperand opnd> :
     InstSE<(outs), (ins opnd:$target), !strconcat(opstr, "\t$target"),
            [], IIBranch, FrmJ, opstr> {
     let DecoderMethod = "DecodeJumpTargetMM";
   }
 
   class JumpLinkRegMM<string opstr, RegisterOperand RO>:
     InstSE<(outs RO:$rd), (ins RO:$rs), !strconcat(opstr, "\t$rd, $rs"),
             [], IIBranch, FrmR>;
+
+  class BranchCompareToZeroLinkMM<string opstr, DAGOperand opnd,
+                                  RegisterOperand RO> :
+    InstSE<(outs), (ins RO:$rs, opnd:$offset),
+           !strconcat(opstr, "\t$rs, $offset"), [], IIBranch, FrmI, opstr>;
 }
 
 def MFHI16_MM : MoveFromHILOMM<"mfhi", GPR32Opnd, AC0>, MFHILO_FM_MM16<0x10>;
 def MFLO16_MM : MoveFromHILOMM<"mflo", GPR32Opnd, AC0>, MFHILO_FM_MM16<0x12>;
 def MOVE16_MM : MoveMM16<"move", GPR32Opnd>, MOVE_FM_MM16<0x03>;
 def JALR16_MM : JumpLinkRegMM16<"jalr", GPR32Opnd>, JALR_FM_MM16<0x0e>;
 
 class WaitMM<string opstr> :
def BLEZ_MM : MMRel, CBranchZero<"blez", brtarget_mm, setle, GPR32Opnd>,
                 BGEZ_FM_MM<0x4>;
   def BLTZ_MM : MMRel, CBranchZero<"bltz", brtarget_mm, setlt, GPR32Opnd>,
                 BGEZ_FM_MM<0x0>;
   def BGEZAL_MM : MMRel, BGEZAL_FT<"bgezal", brtarget_mm, GPR32Opnd>,
                   BGEZAL_FM_MM<0x03>;
   def BLTZAL_MM : MMRel, BGEZAL_FT<"bltzal", brtarget_mm, GPR32Opnd>,
                   BGEZAL_FM_MM<0x01>;
 
+  /// Branch Instructions - Short Delay Slot
+  def BGEZALS_MM : BranchCompareToZeroLinkMM<"bgezals", brtarget_mm,
+                                             GPR32Opnd>, BGEZAL_FM_MM<0x13>;
+  def BLTZALS_MM : BranchCompareToZeroLinkMM<"bltzals", brtarget_mm,
+                                             GPR32Opnd>, BGEZAL_FM_MM<0x11>;
+
   /// Control Instructions
   def SYNC_MM    : MMRel, SYNC_FT<"sync">, SYNC_FM_MM;
   def BREAK_MM   : MMRel, BRK_FT<"break">, BRK_FM_MM;
   def SYSCALL_MM : MMRel, SYS_FT<"syscall">, SYS_FM_MM;
   def WAIT_MM    : WaitMM<"wait">, WAIT_FM_MM;
   def ERET_MM    : MMRel, ER_FT<"eret">, ER_FM_MM<0x3cd>;
   def DERET_MM   : MMRel, ER_FT<"deret">, ER_FM_MM<0x38d>;
   def EI_MM      : MMRel, DEI_FT<"ei", GPR32Opnd>, EI_FM_MM<0x15d>,

llvm/trunk/test/MC/Mips/micromips-branch-instructions.s

 # CHECK-EL: blez $6, 1332        # encoding: [0x86,0x40,0x9a,0x02]
 # CHECK-EL: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EL: bne $9, $6, 1332     # encoding: [0xc9,0xb4,0x9a,0x02]
 # CHECK-EL: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EL: bal 1332             # encoding: [0x60,0x40,0x9a,0x02]
 # CHECK-EL: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EL: bltz $6, 1332        # encoding: [0x06,0x40,0x9a,0x02]
 # CHECK-EL: nop                  # encoding: [0x00,0x00,0x00,0x00]
+# CHECK-EL: bgezals $6, 1332     # encoding: [0x66,0x42,0x9a,0x02]
+# CHECK-EL: move $zero, $zero    # encoding: [0x00,0x0c]
+# CHECK-EL: bltzals $6, 1332     # encoding: [0x26,0x42,0x9a,0x02]
+# CHECK-EL: move $zero, $zero    # encoding: [0x00,0x0c]
 #------------------------------------------------------------------------------
 # Big endian
 #------------------------------------------------------------------------------
 # CHECK-EB: b 1332               # encoding: [0x94,0x00,0x02,0x9a]
 # CHECK-EB: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EB: beq $9, $6, 1332     # encoding: [0x94,0xc9,0x02,0x9a]
 # CHECK-EB: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EB: bgez $6, 1332        # encoding: [0x40,0x46,0x02,0x9a]
 # CHECK-EB: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EB: bgezal $6, 1332      # encoding: [0x40,0x66,0x02,0x9a]
 # CHECK-EB: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EB: bltzal $6, 1332      # encoding: [0x40,0x26,0x02,0x9a]
 # CHECK-EB: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EB: bgtz $6, 1332        # encoding: [0x40,0xc6,0x02,0x9a]
 # CHECK-EB: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EB: blez $6, 1332        # encoding: [0x40,0x86,0x02,0x9a]
 # CHECK-EB: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EB: bne $9, $6, 1332     # encoding: [0xb4,0xc9,0x02,0x9a]
 # CHECK-EB: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EB: bal 1332             # encoding: [0x40,0x60,0x02,0x9a]
 # CHECK-EB: nop                  # encoding: [0x00,0x00,0x00,0x00]
 # CHECK-EB: bltz $6, 1332        # encoding: [0x40,0x06,0x02,0x9a]
 # CHECK-EB: nop                  # encoding: [0x00,0x00,0x00,0x00]
+# CHECK-EB: bgezals $6, 1332     # encoding: [0x42,0x66,0x02,0x9a]
+# CHECK-EB: move $zero, $zero    # encoding: [0x0c,0x00]
+# CHECK-EB: bltzals $6, 1332     # encoding: [0x42,0x26,0x02,0x9a]
+# CHECK-EB: move $zero, $zero    # encoding: [0x0c,0x00]
 
      b      1332
      beq    $9,$6,1332
      bgez   $6,1332
      bgezal $6,1332
      bltzal $6,1332
      bgtz   $6,1332
      blez   $6,1332
      bne    $9,$6,1332
      bal    1332
      bltz   $6,1332
+     bgezals $6,1332
+     bltzals $6,1332