[mips][microMIPS] Implement ERET and ERETNC instructions

[zbuljan]

Summary

The patch implements microMIPSr6 ERET and ERETNC instructions.

[dsanders]

LGTM with a nit

lib/Target/Mips/MicroMips32r6InstrFormats.td

186–204

Nit: Each of these two formats only have one instruction using them. As such, we should remove the 'funct' argument and define the number here.

[dsanders]

lib/Target/Mips/MicroMips32r6InstrFormats.td

186–204

One more nit. 'instr_asm' is unused and should be removed.

[dsanders]

lib/Target/Mips/MicroMips32r6InstrFormats.td

186–204

One more nit. 'instr_asm' is unused and should be removed.

Please ignore that. I was thinking of normal MIPS which doesn't have instruction mnemonics in the formats.

[zbuljan]

Closed by commit rL239522: [mips][microMIPS] Implement ERET and ERETNC instructions

lib/Target/Mips/MicroMips32r6InstrFormats.td

class POOL32A_LSA_FM<bits<6> funct> : MipsR6Inst {
   let Inst{31-26} = 0b000000;
   let Inst{25-21} = rt;
   let Inst{20-16} = rs;
   let Inst{15-11} = rd;
   let Inst{10-9}  = imm2;
   let Inst{8-6}   = 0b000;
   let Inst{5-0}   = funct;
 }
+
+class ERET_FM_MMR6<string instr_asm, bits<10> funct> : MMR6Arch<instr_asm> {
+  bits<32> Inst;
+
+  let Inst{31-26} = 0x00;
+  let Inst{25-16} = 0x00;
+  let Inst{15-6}  = funct;
+  let Inst{5-0}   = 0x3c;
+}
+
+class ERETNC_FM_MMR6<string instr_asm, bits<10> funct> : MMR6Arch<instr_asm> {
+  bits<32> Inst;
+
+  let Inst{31-26} = 0x00;
+  let Inst{25-17} = 0x00;
+  let Inst{16-16} = 0x01;
+  let Inst{15-6}  = funct;
+  let Inst{5-0}   = 0x3c;
+}

lib/Target/Mips/MicroMips32r6InstrInfo.td

 class BALC_MMR6_ENC  : BRANCH_OFF26_FM<0b101101>;
 class BC_MMR6_ENC : BRANCH_OFF26_FM<0b100101>;
 class BITSWAP_MMR6_ENC : POOL32A_BITSWAP_FM_MMR6<0b101100>;
 class CACHE_MMR6_ENC : CACHE_PREF_FM_MMR6<0b001000, 0b0110>;
 class CLO_MMR6_ENC : POOL32A_2R_FM_MMR6<0b0100101100>;
 class CLZ_MMR6_ENC : SPECIAL_2R_FM_MMR6<0b010000>;
 class DIV_MMR6_ENC : ARITH_FM_MMR6<"div", 0x118>;
 class DIVU_MMR6_ENC : ARITH_FM_MMR6<"divu", 0x198>;
+class ERET_MMR6_ENC : ERET_FM_MMR6<"eret", 0x3cd>;
+class ERETNC_MMR6_ENC : ERETNC_FM_MMR6<"eretnc", 0x3cd>;
 class JIALC_MMR6_ENC : JMP_IDX_COMPACT_FM<0b100000>;
 class JIC_MMR6_ENC   : JMP_IDX_COMPACT_FM<0b101000>;
 class LSA_MMR6_ENC : POOL32A_LSA_FM<0b001111>;
 class LWPC_MMR6_ENC  : PCREL19_FM_MMR6<0b01>;
 class MOD_MMR6_ENC : ARITH_FM_MMR6<"mod", 0x158>;
 class MODU_MMR6_ENC : ARITH_FM_MMR6<"modu", 0x1d8>;
 class MUL_MMR6_ENC : ARITH_FM_MMR6<"mul", 0x18>;
 class MUH_MMR6_ENC : ARITH_FM_MMR6<"muh", 0x58>;
class CLO_CLZ_MMR6_DESC_BASE<string instr_asm, RegisterOperand GPROpnd>
   dag OutOperandList = (outs GPROpnd:$rt);
   dag InOperandList = (ins GPROpnd:$rs);
   string AsmString = !strconcat(instr_asm, "\t$rt, $rs");
 }
 
 class CLO_MMR6_DESC : CLO_CLZ_MMR6_DESC_BASE<"clo", GPR32Opnd>;
 class CLZ_MMR6_DESC : CLO_CLZ_MMR6_DESC_BASE<"clz", GPR32Opnd>;
 
+class ERET_MMR6_DESC : ER_FT<"eret">;
+class ERETNC_MMR6_DESC : ER_FT<"eretnc">;
+
 class JMP_MMR6_IDX_COMPACT_DESC_BASE<string opstr, DAGOperand opnd,
                                      RegisterOperand GPROpnd>
     : MMR6Arch<opstr> {
   dag InOperandList = (ins GPROpnd:$rt, opnd:$offset);
   string AsmString = !strconcat(opstr, "\t$rt, $offset");
   list<dag> Pattern = [];
   bit isTerminator = 1;
   bit hasDelaySlot = 0;

 def BC_MMR6 : R6MMR6Rel, BC_MMR6_ENC, BC_MMR6_DESC, ISA_MICROMIPS32R6;
 def BITSWAP_MMR6 : R6MMR6Rel, BITSWAP_MMR6_ENC, BITSWAP_MMR6_DESC,
                    ISA_MICROMIPS32R6;
 def CACHE_MMR6 : R6MMR6Rel, CACHE_MMR6_ENC, CACHE_MMR6_DESC, ISA_MICROMIPS32R6;
 def CLO_MMR6 : R6MMR6Rel, CLO_MMR6_ENC, CLO_MMR6_DESC, ISA_MICROMIPS32R6;
 def CLZ_MMR6 : R6MMR6Rel, CLZ_MMR6_ENC, CLZ_MMR6_DESC, ISA_MICROMIPS32R6;
 def DIV_MMR6 : R6MMR6Rel, DIV_MMR6_DESC, DIV_MMR6_ENC, ISA_MICROMIPS32R6;
 def DIVU_MMR6 : R6MMR6Rel, DIVU_MMR6_DESC, DIVU_MMR6_ENC, ISA_MICROMIPS32R6;
+def ERET_MMR6 : R6MMR6Rel, ERET_MMR6_DESC, ERET_MMR6_ENC, ISA_MICROMIPS32R6;
+def ERETNC_MMR6 : R6MMR6Rel, ERETNC_MMR6_DESC, ERETNC_MMR6_ENC, ISA_MICROMIPS32R6;
 def JIALC_MMR6 : R6MMR6Rel, JIALC_MMR6_ENC, JIALC_MMR6_DESC, ISA_MICROMIPS32R6;
 def JIC_MMR6 : R6MMR6Rel, JIC_MMR6_ENC, JIC_MMR6_DESC, ISA_MICROMIPS32R6;
 def LSA_MMR6 : R6MMR6Rel, LSA_MMR6_ENC, LSA_MMR6_DESC, ISA_MICROMIPS32R6;
 def LWPC_MMR6 : R6MMR6Rel, LWPC_MMR6_ENC, LWPC_MMR6_DESC, ISA_MICROMIPS32R6;
 def MOD_MMR6 : R6MMR6Rel, MOD_MMR6_DESC, MOD_MMR6_ENC, ISA_MICROMIPS32R6;
 def MODU_MMR6 : R6MMR6Rel, MODU_MMR6_DESC, MODU_MMR6_ENC, 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;

lib/Target/Mips/MipsInstrInfo.td

 def TNEI : MMRel, TEQI_FT<"tnei", GPR32Opnd>, TEQI_FM<0xe>,
            ISA_MIPS2_NOT_32R6_64R6;
 
 def BREAK : MMRel, BRK_FT<"break">, BRK_FM<0xd>;
 def SYSCALL : MMRel, SYS_FT<"syscall">, SYS_FM<0xc>;
 def TRAP : TrapBase<BREAK>;
 def SDBBP : MMRel, SYS_FT<"sdbbp">, SDBBP_FM, ISA_MIPS32_NOT_32R6_64R6;
 
+let AdditionalPredicates = [NotInMicroMips] in {
 def ERET : MMRel, ER_FT<"eret">, ER_FM<0x18>, INSN_MIPS3_32;
+}
 def DERET : MMRel, ER_FT<"deret">, ER_FM<0x1f>, ISA_MIPS32;
 
 def EI : MMRel, DEI_FT<"ei", GPR32Opnd>, EI_FM<1>, ISA_MIPS32R2;
 def DI : MMRel, DEI_FT<"di", GPR32Opnd>, EI_FM<0>, ISA_MIPS32R2;
 
 let EncodingPredicates = []<Predicate>, // FIXME: Lack of HasStdEnc is probably a bug
     AdditionalPredicates = [NotInMicroMips] in {
 def WAIT : WAIT_FT<"wait">, WAIT_FM;

test/MC/Disassembler/Mips/micromips32r6.txt

 0x01 0x65 0x4b 0x3c # CHECK: clo $11, $5
 
 0x03 0x80 0xe8 0x50 # CHECK: clz $sp, $gp
 
 0x00 0xa4 0x19 0x18 # CHECK: div $3, $4, $5
 
 0x00 0xa4 0x19 0x98 # CHECK: divu $3, $4, $5
 
+0x00 0x00 0xf3 0x7c # CHECK: eret
+
+0x00 0x01 0xf3 0x7c # CHECK: eretnc
+
 0x80 0x05 0x01 0x00 # CHECK: jialc $5, 256
 
 0xa0 0x05 0x01 0x00 # CHECK: jic $5, 256
 
 0x78 0x48 0x00 0x43 # CHECK: lwpc $2, 268
 
 0x00 0x43 0x26 0x0f # CHECK: lsa $2, $3, $4, 3
 

test/MC/Mips/micromips32r6/valid.s

# RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips32r6 -mattr=micromips | FileCheck %s
   balc 14572256            # CHECK: balc 14572256       # encoding: [0xb4,0x37,0x96,0xb8]
   bc 14572256              # CHECK: bc 14572256         # encoding: [0x94,0x37,0x96,0xb8]
   bitswap $4, $2           # CHECK: bitswap $4, $2      # encoding: [0x00,0x44,0x0b,0x3c]
   cache 1, 8($5)           # CHECK: cache 1, 8($5)      # encoding: [0x20,0x25,0x60,0x08]
   clo $11, $a1             # CHECK: clo $11, $5         # encoding: [0x01,0x65,0x4b,0x3c]
   clz $sp, $gp             # CHECK: clz $sp, $gp        # encoding: [0x03,0x80,0xe8,0x50]
   div $3, $4, $5           # CHECK: div $3, $4, $5      # encoding: [0x00,0xa4,0x19,0x18]
   divu $3, $4, $5          # CHECK: divu $3, $4, $5     # encoding: [0x00,0xa4,0x19,0x98]
+  eret                     # CHECK: eret                # encoding: [0x00,0x00,0xf3,0x7c]
+  eretnc                   # CHECK: eretnc              # encoding: [0x00,0x01,0xf3,0x7c]
   jialc $5, 256            # CHECK: jialc $5, 256       # encoding: [0x80,0x05,0x01,0x00]
   jic   $5, 256            # CHECK: jic $5, 256         # encoding: [0xa0,0x05,0x01,0x00]
   lsa $2, $3, $4, 3        # CHECK: lsa  $2, $3, $4, 3  # encoding: [0x00,0x43,0x26,0x0f]
   lwpc    $2,268           # CHECK: lwpc $2, 268        # encoding: [0x78,0x48,0x00,0x43]
   mod $3, $4, $5           # CHECK: mod $3, $4, $5      # encoding: [0x00,0xa4,0x19,0x58]
   modu $3, $4, $5          # CHECK: modu $3, $4, $5     # encoding: [0x00,0xa4,0x19,0xd8]
   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]
   seleqz $2,$3,$4          # CHECK: seleqz $2, $3, $4   # encoding: [0x00,0x83,0x11,0x40]
   selnez $2,$3,$4          # CHECK: selnez $2, $3, $4   # encoding: [0x00,0x83,0x11,0x80]
   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]