Add back ReverseElementBits intrinsic.

Author: vargaz

src/mono/mono/mini/llvm-intrinsics.h

@@ -261,6 +261,7 @@ INTRINS_OVR(WASM_ANYTRUE_V2, wasm_anytrue, Wasm, sse_i8_t)
 #if defined(TARGET_ARM64)
 INTRINS_OVR(BITREVERSE_I32, bitreverse, Generic, LLVMInt32Type ())
 INTRINS_OVR(BITREVERSE_I64, bitreverse, Generic, LLVMInt64Type ())
+INTRINS_OVR_TAG(BITREVERSE, bitreverse, Generic, V64 | V128 | I1 | I2 | I4 | I8)
 INTRINS(AARCH64_CRC32B, aarch64_crc32b, Arm64)
 INTRINS(AARCH64_CRC32H, aarch64_crc32h, Arm64)
 INTRINS(AARCH64_CRC32W, aarch64_crc32w, Arm64)
@@ -399,6 +400,10 @@ INTRINS_OVR_TAG(AARCH64_ADV_SIMD_FRSQRTE, aarch64_neon_frsqrte, Arm64, Scalar |
 INTRINS_OVR_TAG(AARCH64_ADV_SIMD_FRSQRTS, aarch64_neon_frsqrts, Arm64, Scalar | V64 | V128 | R4 | R8)
 INTRINS_OVR_TAG(AARCH64_ADV_SIMD_FRECPS, aarch64_neon_frecps, Arm64, Scalar | V64 | V128 | R4 | R8)
 
+#if LLVM_API_VERSION < 1400
+INTRINS_OVR_TAG(AARCH64_ADV_SIMD_RBIT, aarch64_neon_rbit, Arm64, V64 | V128 | I1)
+#endif
+
 INTRINS_OVR_TAG(AARCH64_ADV_SIMD_FRINTA, round, Generic, Scalar | V64 | V128 | R4 | R8)
 #if LLVM_API_VERSION < 1400
 INTRINS_OVR_TAG(AARCH64_ADV_SIMD_FRINTN, aarch64_neon_frintn, Arm64, Scalar | V64 | V128 | R4 | R8)

src/mono/mono/mini/simd-intrinsics.c

@@ -2517,6 +2517,11 @@ static SimdIntrinsic advsimd_methods [] = {
 	{SN_ReverseElement16, OP_ARM64_REVN, 16},
 	{SN_ReverseElement32, OP_ARM64_REVN, 32},
 	{SN_ReverseElement8, OP_ARM64_REVN, 8},
+#if LLVM_API_VERSION >= 1400
+	{SN_ReverseElementBits, OP_XOP_OVR_X_X, INTRINS_BITREVERSE},
+#else
+	{SN_ReverseElementBits, OP_XOP_OVR_X_X, INTRINS_AARCH64_ADV_SIMD_RBIT},
+#endif
 	{SN_RoundAwayFromZero, OP_XOP_OVR_X_X, INTRINS_AARCH64_ADV_SIMD_FRINTA},
 	{SN_RoundAwayFromZeroScalar, OP_XOP_OVR_SCALAR_X_X, INTRINS_AARCH64_ADV_SIMD_FRINTA},
 #if LLVM_API_VERSION >= 1400