Commit e0c7f900 authored by Jan Beulich's avatar Jan Beulich Committed by Jan Beulich

x86: tighten condition for emitting LOCK on control register accesses

The control register is never expressed by REX.B; this bit only affects
the involved GPR. Also only one of the operands can have its "control"
flag set, so only check the correct operand.
parent 64795710
2018-06-01 Jan Beulich <jbeulich@suse.com>
* config/tc-i386.c (build_modrm_byte): Drop REX_B from condition
checking for the need of emitting LOCK. Check "control" bit just
once.
2018-06-01 Jan Beulich <jbeulich@suse.com>
* testsuite/gas/i386/invpcid.s,
......
......@@ -6894,12 +6894,11 @@ build_modrm_byte (void)
if ((i.op[source].regs->reg_flags & RegVRex) != 0)
i.vrex |= REX_R;
}
if (flag_code != CODE_64BIT && (i.rex & (REX_R | REX_B)))
if (flag_code != CODE_64BIT && (i.rex & REX_R))
{
if (!i.types[0].bitfield.control
&& !i.types[1].bitfield.control)
if (!i.types[i.tm.operand_types[0].bitfield.regmem].bitfield.control)
abort ();
i.rex &= ~(REX_R | REX_B);
i.rex &= ~REX_R;
add_prefix (LOCK_PREFIX_OPCODE);
}
}
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment