[Bug binutils/10973] New: OP_E_memory produces wrong disassembled code

[spop at gcc dot gnu dot org]

The following patterns are not disassembled correctly for the
registers (rbp, rsp, r12, r13) and for any of the instructions of FMA4
or XOP with four operands.

        vfmaddpd       %xmm10,(%rbp),%xmm5,%xmm11
        vfmaddpd       %xmm10,(%rsp),%xmm5,%xmm11
        VPMACSDD       %xmm10,(%r12),%xmm5,%xmm11
        VPMACSDD       %xmm10,(%r13),%xmm5,%xmm11

wrongly disassembled like this:

   0:   c4 63 51 69 5d 00 a0    vfmaddpd %xmm12,0x5d(%rbp),%xmm5,%xmm11
   7:   c4 63 51 69 1c 24 a0    vfmaddpd %xmm8,(%rsp,%rbx,1),%xmm5,%xmm11
   e:   8f 48 50 9e 1c 24 a0    vpmacsdd %xmm8,(%r12,%rbx,1),%xmm5,%xmm11
  15:   8f 48 50 9e 5d 00 a0    vpmacsdd %xmm6,0x5d(%r13),%xmm5,%xmm11

The disassembler gets confused in OP_E_memory, that makes me suspect
that this bug is also present in other instructions using OP_E_memory.

Furthermore, the assembler seems to try to accommodate this bug by
using a fake_zero_displacement exactly in the cases that we were hit
in the disassembler:

              /* x86-64 ignores REX prefix bit here to avoid decoder
                 complications.  */
              if ((i.base_reg->reg_num & 7) == EBP_REG_NUM)
                {
                  default_seg = &ss;
                  if (i.disp_operands == 0)
                    {
                      fake_zero_displacement = 1;
                      i.types[op].bitfield.disp8 = 1;
                    }
                }

-- 
           Summary: OP_E_memory produces wrong disassembled code
           Product: binutils
           Version: 2.21 (HEAD)
            Status: NEW
          Severity: normal
          Priority: P2
         Component: binutils
        AssignedTo: unassigned at sources dot redhat dot com
        ReportedBy: spop at gcc dot gnu dot org
                CC: bug-binutils at gnu dot org


http://sourceware.org/bugzilla/show_bug.cgi?id=10973

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