PowerPC64LE subfo. instruction fails to disassemble

[shawnanastasio]

Capstone 4.0.2 fails to disassemble subfo., the OE=1 Rc=1 form of the Subtract From XO-form instruction (Primary Opcode 31) on PowerPC64LE.

Simple reproducer:

#include <stdio.h>
#include <stdint.h>

#include <capstone/capstone.h>

static const uint8_t code[] = {
    0x51, 0x64, 0x0d, 0x7c, /* subfo. r0, r13, r12 */
};

int main(void) {
    csh handle;
    cs_insn *insn;
    size_t count;

    if (cs_open(CS_ARCH_PPC, CS_MODE_64 + CS_MODE_LITTLE_ENDIAN, &handle) != CS_ERR_OK)
        return 1;

    count = cs_disasm(handle, code, sizeof(code), 0, 0, &insn);
    printf("disassembled instruction count: %zu\n", count); // -> prints 0
}

[shawnanastasio]

Confirmed reproducible on latest commit 4457d45.