[mips][microMIPSr6] Implement SEB and SEH instructions

[jkolek]

LGTM.

lib/Target/Mips/MicroMips32r6InstrFormats.td

class ADDI_FM_MMR6<string instr_asm, bits<6> op> : MMR6Arch<instr_asm> {
   bits<32> Inst;
 
   let Inst{31-26} = op;
   let Inst{25-21} = rt;
   let Inst{20-16} = rs;
   let Inst{15-0}  = imm16;
 }
 
+class SIGN_EXTEND_FM_MMR6<string instr_asm, bits<10> funct>
+    : MMR6Arch<instr_asm> {
+  bits<5> rd;
+  bits<5> rt;
+
+  bits<32> Inst;
+
+  let Inst{31-26} = 0b000000;
+  let Inst{25-21} = rd;
+  let Inst{20-16} = rt;
+  let Inst{15-6}  = funct;
+  let Inst{5-0}   = 0b111100;
+}
+
 class PCREL19_FM_MMR6<bits<2> funct> : MipsR6Inst {
   bits<5> rt;
   bits<19> imm;
 
   bits<32> Inst;
 
   let Inst{31-26} = 0b011110;
   let Inst{25-21} = rt;

lib/Target/Mips/MicroMips32r6InstrInfo.td

 class LWPC_MMR6_ENC  : PCREL19_FM_MMR6<0b01>;
 class MUL_MMR6_ENC : ARITH_FM_MMR6<"mul", 0x18>;
 class MUH_MMR6_ENC : ARITH_FM_MMR6<"muh", 0x58>;
 class MULU_MMR6_ENC : ARITH_FM_MMR6<"mulu", 0x98>;
 class MUHU_MMR6_ENC : ARITH_FM_MMR6<"muhu", 0xd8>;
 class PREF_MMR6_ENC : CACHE_PREF_FM_MMR6<0b011000, 0b0010>;
 class SUB_MMR6_ENC : ARITH_FM_MMR6<"sub", 0x190>;
 class SUBU_MMR6_ENC : ARITH_FM_MMR6<"subu", 0x1d0>;
+class SEB_MMR6_ENC : SIGN_EXTEND_FM_MMR6<"seb", 0b0010101100>;
+class SEH_MMR6_ENC : SIGN_EXTEND_FM_MMR6<"seh", 0b0011101100>;
 
 //===----------------------------------------------------------------------===//
 //
 // Instruction Descriptions
 //
 //===----------------------------------------------------------------------===//
 
 class ADD_MMR6_DESC : ArithLogicR<"add", GPR32Opnd>;

 }
 
 class JIC_MMR6_DESC : JMP_MMR6_IDX_COMPACT_DESC_BASE<"jic", jmpoffset16,
                                                      GPR32Opnd> {
   bit isBarrier = 1;
   list<Register> Defs = [AT];
 }
 
+class SEB_MMR6_DESC : SignExtInReg<"seb", i8, GPR32Opnd, II_SEB>;
+class SEH_MMR6_DESC : SignExtInReg<"seh", i16, GPR32Opnd, II_SEH>;
 class ALUIPC_MMR6_DESC_BASE<string instr_asm, RegisterOperand GPROpnd>
     : MMR6Arch<instr_asm> {
   dag OutOperandList = (outs GPROpnd:$rt);
   dag InOperandList = (ins simm16:$imm);
   string AsmString = !strconcat(instr_asm, "\t$rt, $imm");
   list<dag> Pattern = [];
 }
 

 def LWPC_MMR6 : R6MMR6Rel, LWPC_MMR6_ENC, LWPC_MMR6_DESC, ISA_MICROMIPS32R6;
 def MUL_MMR6 : R6MMR6Rel, MUL_MMR6_DESC, MUL_MMR6_ENC, ISA_MICROMIPS32R6;
 def MUH_MMR6 : R6MMR6Rel, MUH_MMR6_DESC, MUH_MMR6_ENC, ISA_MICROMIPS32R6;
 def MULU_MMR6 : R6MMR6Rel, MULU_MMR6_DESC, MULU_MMR6_ENC, ISA_MICROMIPS32R6;
 def MUHU_MMR6 : R6MMR6Rel, MUHU_MMR6_DESC, MUHU_MMR6_ENC, ISA_MICROMIPS32R6;
 def PREF_MMR6 : R6MMR6Rel, PREF_MMR6_ENC, PREF_MMR6_DESC, ISA_MICROMIPS32R6;
 def SUB_MMR6 : StdMMR6Rel, SUB_MMR6_DESC, SUB_MMR6_ENC, ISA_MICROMIPS32R6;
 def SUBU_MMR6 : StdMMR6Rel, SUBU_MMR6_DESC, SUBU_MMR6_ENC, ISA_MICROMIPS32R6;
+def SEB_MMR6 : StdMMR6Rel, SEB_MMR6_DESC, SEB_MMR6_ENC, ISA_MICROMIPS32R6;
+def SEH_MMR6 : StdMMR6Rel, SEH_MMR6_DESC, SEH_MMR6_ENC, ISA_MICROMIPS32R6;
 }

lib/Target/Mips/MipsInstrInfo.td

let EncodingPredicates = []<Predicate>, // FIXME: Lack of HasStdEnc is probably a bug
     AdditionalPredicates = [NotInMicroMips] in {
 def MFHI : MMRel, MoveFromLOHI<"mfhi", GPR32Opnd, AC0>, MFLO_FM<0x10>,
            ISA_MIPS1_NOT_32R6_64R6;
 def MFLO : MMRel, MoveFromLOHI<"mflo", GPR32Opnd, AC0>, MFLO_FM<0x12>,
            ISA_MIPS1_NOT_32R6_64R6;
 }
 
 /// Sign Ext In Register Instructions.
-def SEB : MMRel, SignExtInReg<"seb", i8, GPR32Opnd, II_SEB>,
+def SEB : MMRel, StdMMR6Rel, SignExtInReg<"seb", i8, GPR32Opnd, II_SEB>,
           SEB_FM<0x10, 0x20>, ISA_MIPS32R2;
-def SEH : MMRel, SignExtInReg<"seh", i16, GPR32Opnd, II_SEH>,
+def SEH : MMRel, StdMMR6Rel, SignExtInReg<"seh", i16, GPR32Opnd, II_SEH>,
           SEB_FM<0x18, 0x20>, ISA_MIPS32R2;
 
 /// Count Leading
 def CLZ : MMRel, CountLeading0<"clz", GPR32Opnd>, CLO_FM<0x20>,
           ISA_MIPS32_NOT_32R6_64R6;
 def CLO : MMRel, CountLeading1<"clo", GPR32Opnd>, CLO_FM<0x21>,
           ISA_MIPS32_NOT_32R6_64R6;
 

test/MC/Disassembler/Mips/micromips32r6.txt

 
 # CHECK: pref 1, 8($5)
 0x60 0x25 0x20 0x08
 
 0x00 0xa4 0x19 0x90 # CHECK: sub $3, $4, $5
 
 0x00 0xa4 0x19 0xd0 # CHECK: subu $3, $4, $5
 
+0x00 0x64 0x2b 0x3c # CHECK: seb $3, $4
+
+0x00 0x64 0x3b 0x3c # CHECK: seh $3, $4
+

test/MC/Mips/micromips32r6/valid.s

# RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips32r6 -mattr=micromips | FileCheck %s
   lwpc    $2,268           # CHECK: lwpc $2, 268        # encoding: [0x78,0x48,0x00,0x43]
   mul $3, $4, $5           # CHECK mul $3, $4, $5       # encoding: [0x00,0xa4,0x18,0x18]
   muh $3, $4, $5           # CHECK muh $3, $4, $5       # encoding: [0x00,0xa4,0x18,0x58]
   mulu $3, $4, $5          # CHECK mulu $3, $4, $5      # encoding: [0x00,0xa4,0x18,0x98]
   muhu $3, $4, $5          # CHECK muhu $3, $4, $5      # encoding: [0x00,0xa4,0x18,0xd8]
   pref 1, 8($5)            # CHECK: pref 1, 8($5)       # encoding: [0x60,0x25,0x20,0x08]
   sub $3, $4, $5           # CHECK: sub $3, $4, $5      # encoding: [0x00,0xa4,0x19,0x90]
   subu $3, $4, $5          # CHECK: subu $3, $4, $5     # encoding: [0x00,0xa4,0x19,0xd0]
+  seb $3, $4               # CHECK: seb $3, $4          # encoding: [0x00,0x64,0x2b,0x3c]
+  seh $3, $4               # CHECK: seh $3, $4          # encoding: [0x00,0x64,0x3b,0x3c]