BFCSEL's else-target turned out to be the implicit fall-through, so the
BF_BELSE operand encoding, the BFCSEL_ELSE_T32 relocation, and their
encoder/decoder cases were never referenced by any table entry. Remove
them. Also restructure the MSA COPY specgen loop so COPY_U only iterates
.B/.H (COPY_U.W is mips64-only and emitted in the mips64 section), which
drops the spurious 'skipped COPY_U_W' message. No functional change to any
generated encode form; arm64/arm32/mips all still 100%, 461/600/281 tests
green.
New REL19/REL18 operand types + BRANCH_19/BRANCH_18 encodings + REL_PC19/
REL_PC18 relocations (R6 PC-relative semantics: offset is relative to the
instruction's own address, no delay-slot adjustment; LDPC aligns the PC
down to 8 and scales by 8). LWPC (mips32r6), LWUPC/LDPC (mips64r6).
Byte-exact vs llvm-mc and decode-clean; 281 tests green.
Parameterize the specgen oracle with a per-family llvm-mc command so
64-bit-FPU and mips64 forms can be assembled. Paired-single CVT_PS_S,
CVT_S_PL/PU, PLL/PLU/PUL/PUU.PS (via -mcpu=mips64r2). mips64-only MSA
INSERT_D and COPY_U_W (via the mips64 triple). Byte-exact vs llvm-mc and
decode-clean; 281 tests green.
New EXT_SIZE encoding (5-bit extract size at 25:21). EXTPDP (immediate
size), and the variable forms EXTPDPV / EXTRV_R.W / EXTRV_RS.W / EXTRV_S.H
(extract via a GPR-specified position). Byte-exact vs llvm-mc and decode-
clean; 281 tests green.
New AC_NUM (accumulator ac0..ac3 at bits 12:11) and SHILO_IMM (signed
6-bit at 25:20) encodings. DPA/DPAX/DPS/DPSX.W.PH and MAQ_S/MAQ_SA.W.PHL/
PHR (multiply-accumulate into a DSP accumulator), plus MTHLIP, SHILOV and
SHILO (accumulator shift). Spot-checked byte-exact vs llvm-mc and decode-
clean, including a negative SHILO immediate; 281 tests green.
BZ/BNZ .B/.H/.W/.D/.V (branch if any/all elements zero/non-zero): a
specgen branch emitter that derives the opcode+Wt bits then marks the
16-bit PC-relative offset variable, reusing the existing REL16/BRANCH_16
relocation machinery. The offset is emitted as a relocation (label
target). 10 forms, opcode+Wt byte-exact vs llvm-mc and decode-clean.
The R6 two-/one-register compact branches (BEQC/BNEC/BLTC/BGEC/.../BLTZC)
are deferred: they share POP major opcodes disambiguated only by the
rs/rt relationship, which the opcode+mask decode model can't express
without operand-aware logic. 281 tests green.
New FR (FP reg at 25:21) encoding for the COP1X 4-register fused
multiply-adds MADD/MSUB/NMADD/NMSUB.S/.D. New GPR_AT_6 / GPR_AT_11
encodings (GPR in a vector-register slot, with correct GPR decode) for
MSA COPY_S/U (lane->GPR) and INSERT (GPR->lane). DSP two-register
PRECEQU/PRECEU (.PH.QBLA/QBRA) and REPLV (.PH/.QB). Control ops DI/EI and
RDHWR. 25 forms; spot-checked byte-exact vs llvm-mc and decode-clean; 281
tests green.
MOVN/MOVZ.S/.D (FP move on GPR nonzero/zero, enc {FD,FS,RT}), MOVF/MOVT.
S/.D (FP move on FP condition code, enc {FD,FS,FCC_BC}), and the
convert-to-FP forms FCVT_D_W/S_D/S_W (cvt.d.w/cvt.s.d/cvt.s.w). 11 forms.
Spot-checked byte-exact vs llvm-mc and decode-clean; 281 tests green.
MSA INSVE (.B/.H/.W/.D element insert). DSP ASE three-register ops
(ADDU/SUBU/MULEQ/MULEU/MULQ/PRECRQ*/PICK/CMPGU, enc {RD,RS,RT}), the
variable shifts SHLLV/SHRAV/SHRLV (enc {RD,RT,RS} -- value is Rt, shift is
Rs), and the compares CMP/CMPU (.PH/.QB, {RS,RT}). 38 forms reusing the
existing GPR R-type slots. Spot-checked byte-exact vs llvm-mc; 281 tests
green.
New MSA_BIT_SHIFT / MSA_ELM_IDX / MSA_I8 encodings (the data-format marker
is fixed in the entry bits; the operand drives the low bits; decode infers
df from the marker). SLLI/SRAI/SRLI (.B/.H/.W/.D shift), SPLATI/SLDI
(element index), SPLAT/SLD (GPR index), VSHF (.B/.H/.W/.D shuffle), and
the I8 forms ANDI/ORI/XORI/NORI/BMNZI/BMZI/BSELI.B + SHF.B/H/W. 42 forms.
Spot-checked byte-exact vs llvm-mc and decode-clean across all formats;
281 tests green.
