[AArch64] PR target/20667, fix disassembler for the "special" optional SYS_Rt operand for "ic"/"tlbi"

[Jiong Wang <jiong dot wang at foss dot arm dot com>]

"ic/tlbi" are taking "special" optional operands.  They always take one
mandatory operand which is "ic_op"/"tlbi_op".  Some of these "ic_op/tlbi_op"
take one additional "Rt" register operand, the other take nothing.  For either,
the additional operand is never optional with a given "ic_op/tlbi_op".

AArch64 assembler implemented this by firstly treating "ic/tlbi" as taking
optional operand, then doing a later check on the "ic_op/tlbi_op" in
"operand_general_constraint_met_p".  If the "ic_op/tlbi_op" requires additional
operand and there isn't (operand->present be false), error will be issued.  For
example we won't accept "ic ivau" as "ivau" is defined to take one "Rt" register
operand.

However, disassembler haven't understood this.  For "ic ivau, xzr", it's printing
"ic ivau".

This patch fixed this by always print the operand if the operand is present for
"ic/tlbi", they are the only ones using the special "SYS_Rt" operand.

OK for master?


gas/
2016-10-05  Jiong Wang  <jiong.wang@arm.com>

        PR target/20667
        * testsuite/gas/aarch64/sys-rt-reg.s: Test source for instructions
        using SYS_Rt reg.
        * testsuite/gas/aarch64/sys-rt-reg.d: New testcase.


opcodes/
2016-10-05  Jiong Wang  <jiong.wang@arm.com>

        PR target/20667
        * aarch64-opc.c (aarch64_print_operand): Always print operand if
        it's available.

diff --git a/gas/testsuite/gas/aarch64/sys-rt-reg.d b/gas/testsuite/gas/aarch64/sys-rt-reg.d
new file mode 100644
index 0000000000000000000000000000000000000000..4cca4f7db3a40377cae1e98d555367dfafc086bb
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/sys-rt-reg.d
@@ -0,0 +1,134 @@
+#objdump: -dr
+
+.*:     file format .*
+
+Disassembly of section \.text:
+
+.* <.*>:
+.*:	d508711f 	ic	ialluis
+.*:	d508751f 	ic	iallu
+.*:	d50b7520 	ic	ivau, x0
+.*:	d50b7523 	ic	ivau, x3
+.*:	d50b752f 	ic	ivau, x15
+.*:	d50b753a 	ic	ivau, x26
+.*:	d50b753f 	ic	ivau, xzr
+.*:	d508871f 	tlbi	vmalle1
+.*:	d508831f 	tlbi	vmalle1is
+.*:	d50c87df 	tlbi	vmalls12e1
+.*:	d50c83df 	tlbi	vmalls12e1is
+.*:	d50c871f 	tlbi	alle2
+.*:	d50c831f 	tlbi	alle2is
+.*:	d50c879f 	tlbi	alle1
+.*:	d50c839f 	tlbi	alle1is
+.*:	d50e871f 	tlbi	alle3
+.*:	d50e831f 	tlbi	alle3is
+.*:	d5088720 	tlbi	vae1, x0
+.*:	d5088723 	tlbi	vae1, x3
+.*:	d508872f 	tlbi	vae1, x15
+.*:	d508873a 	tlbi	vae1, x26
+.*:	d508873f 	tlbi	vae1, xzr
+.*:	d5088740 	tlbi	aside1, x0
+.*:	d5088743 	tlbi	aside1, x3
+.*:	d508874f 	tlbi	aside1, x15
+.*:	d508875a 	tlbi	aside1, x26
+.*:	d508875f 	tlbi	aside1, xzr
+.*:	d5088760 	tlbi	vaae1, x0
+.*:	d5088763 	tlbi	vaae1, x3
+.*:	d508876f 	tlbi	vaae1, x15
+.*:	d508877a 	tlbi	vaae1, x26
+.*:	d508877f 	tlbi	vaae1, xzr
+.*:	d5088320 	tlbi	vae1is, x0
+.*:	d5088323 	tlbi	vae1is, x3
+.*:	d508832f 	tlbi	vae1is, x15
+.*:	d508833a 	tlbi	vae1is, x26
+.*:	d508833f 	tlbi	vae1is, xzr
+.*:	d5088340 	tlbi	aside1is, x0
+.*:	d5088343 	tlbi	aside1is, x3
+.*:	d508834f 	tlbi	aside1is, x15
+.*:	d508835a 	tlbi	aside1is, x26
+.*:	d508835f 	tlbi	aside1is, xzr
+.*:	d5088360 	tlbi	vaae1is, x0
+.*:	d5088363 	tlbi	vaae1is, x3
+.*:	d508836f 	tlbi	vaae1is, x15
+.*:	d508837a 	tlbi	vaae1is, x26
+.*:	d508837f 	tlbi	vaae1is, xzr
+.*:	d50c8020 	tlbi	ipas2e1is, x0
+.*:	d50c8023 	tlbi	ipas2e1is, x3
+.*:	d50c802f 	tlbi	ipas2e1is, x15
+.*:	d50c803a 	tlbi	ipas2e1is, x26
+.*:	d50c803f 	tlbi	ipas2e1is, xzr
+.*:	d50c80a0 	tlbi	ipas2le1is, x0
+.*:	d50c80a3 	tlbi	ipas2le1is, x3
+.*:	d50c80af 	tlbi	ipas2le1is, x15
+.*:	d50c80ba 	tlbi	ipas2le1is, x26
+.*:	d50c80bf 	tlbi	ipas2le1is, xzr
+.*:	d50c8420 	tlbi	ipas2e1, x0
+.*:	d50c8423 	tlbi	ipas2e1, x3
+.*:	d50c842f 	tlbi	ipas2e1, x15
+.*:	d50c843a 	tlbi	ipas2e1, x26
+.*:	d50c843f 	tlbi	ipas2e1, xzr
+.*:	d50c84a0 	tlbi	ipas2le1, x0
+.*:	d50c84a3 	tlbi	ipas2le1, x3
+.*:	d50c84af 	tlbi	ipas2le1, x15
+.*:	d50c84ba 	tlbi	ipas2le1, x26
+.*:	d50c84bf 	tlbi	ipas2le1, xzr
+.*:	d50c8720 	tlbi	vae2, x0
+.*:	d50c8723 	tlbi	vae2, x3
+.*:	d50c872f 	tlbi	vae2, x15
+.*:	d50c873a 	tlbi	vae2, x26
+.*:	d50c873f 	tlbi	vae2, xzr
+.*:	d50c8320 	tlbi	vae2is, x0
+.*:	d50c8323 	tlbi	vae2is, x3
+.*:	d50c832f 	tlbi	vae2is, x15
+.*:	d50c833a 	tlbi	vae2is, x26
+.*:	d50c833f 	tlbi	vae2is, xzr
+.*:	d50e8720 	tlbi	vae3, x0
+.*:	d50e8723 	tlbi	vae3, x3
+.*:	d50e872f 	tlbi	vae3, x15
+.*:	d50e873a 	tlbi	vae3, x26
+.*:	d50e873f 	tlbi	vae3, xzr
+.*:	d50e8320 	tlbi	vae3is, x0
+.*:	d50e8323 	tlbi	vae3is, x3
+.*:	d50e832f 	tlbi	vae3is, x15
+.*:	d50e833a 	tlbi	vae3is, x26
+.*:	d50e833f 	tlbi	vae3is, xzr
+.*:	d50883a0 	tlbi	vale1is, x0
+.*:	d50883a3 	tlbi	vale1is, x3
+.*:	d50883af 	tlbi	vale1is, x15
+.*:	d50883ba 	tlbi	vale1is, x26
+.*:	d50883bf 	tlbi	vale1is, xzr
+.*:	d50c83a0 	tlbi	vale2is, x0
+.*:	d50c83a3 	tlbi	vale2is, x3
+.*:	d50c83af 	tlbi	vale2is, x15
+.*:	d50c83ba 	tlbi	vale2is, x26
+.*:	d50c83bf 	tlbi	vale2is, xzr
+.*:	d50e83a0 	tlbi	vale3is, x0
+.*:	d50e83a3 	tlbi	vale3is, x3
+.*:	d50e83af 	tlbi	vale3is, x15
+.*:	d50e83ba 	tlbi	vale3is, x26
+.*:	d50e83bf 	tlbi	vale3is, xzr
+.*:	d50883e0 	tlbi	vaale1is, x0
+.*:	d50883e3 	tlbi	vaale1is, x3
+.*:	d50883ef 	tlbi	vaale1is, x15
+.*:	d50883fa 	tlbi	vaale1is, x26
+.*:	d50883ff 	tlbi	vaale1is, xzr
+.*:	d50887a0 	tlbi	vale1, x0
+.*:	d50887a3 	tlbi	vale1, x3
+.*:	d50887af 	tlbi	vale1, x15
+.*:	d50887ba 	tlbi	vale1, x26
+.*:	d50887bf 	tlbi	vale1, xzr
+.*:	d50c87a0 	tlbi	vale2, x0
+.*:	d50c87a3 	tlbi	vale2, x3
+.*:	d50c87af 	tlbi	vale2, x15
+.*:	d50c87ba 	tlbi	vale2, x26
+.*:	d50c87bf 	tlbi	vale2, xzr
+.*:	d50e87a0 	tlbi	vale3, x0
+.*:	d50e87a3 	tlbi	vale3, x3
+.*:	d50e87af 	tlbi	vale3, x15
+.*:	d50e87ba 	tlbi	vale3, x26
+.*:	d50e87bf 	tlbi	vale3, xzr
+.*:	d50887e0 	tlbi	vaale1, x0
+.*:	d50887e3 	tlbi	vaale1, x3
+.*:	d50887ef 	tlbi	vaale1, x15
+.*:	d50887fa 	tlbi	vaale1, x26
+.*:	d50887ff 	tlbi	vaale1, xzr
diff --git a/gas/testsuite/gas/aarch64/sys-rt-reg.s b/gas/testsuite/gas/aarch64/sys-rt-reg.s
new file mode 100644
index 0000000000000000000000000000000000000000..c5f5a700ec48fb8b5e1f78f724bcfe9a6b8006d0
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/sys-rt-reg.s
@@ -0,0 +1,21 @@
+// sys-rt-reg.s Test file for AArch64 instructions take SYS_Rt register.
+
+	.text
+
+	.irp	ic_op, ialluis, iallu
+	ic	\ic_op
+	.endr
+
+	.irp	rt, x0, x3, x15, x26, xzr
+	ic	ivau, \rt
+	.endr
+
+	.irp	tlbi_op, vmalle1, vmalle1is, vmalls12e1, vmalls12e1is, alle2, alle2is, alle1, alle1is, alle3, alle3is
+	tlbi	\tlbi_op
+	.endr
+
+	.irp	tlbi_op, vae1, aside1, vaae1, vae1is, aside1is, vaae1is, ipas2e1is, ipas2le1is, ipas2e1, ipas2le1, vae2, vae2is, vae3, vae3is, vale1is, vale2is, vale3is, vaale1is, vale1, vale2, vale3, vaale1
+	.irp    rt, x0, x3, x15, x26, xzr
+	tlbi	\tlbi_op, \rt
+	.endr
+	.endr
diff --git a/opcodes/aarch64-opc.c b/opcodes/aarch64-opc.c
index 4b1411f4ba6e1cbd6c78bacffffd4daaecf69d3c..333be5ac025282a32d9c9a3d0c64b88e1a1a116b 100644
--- a/opcodes/aarch64-opc.c
+++ b/opcodes/aarch64-opc.c
@@ -2970,11 +2970,15 @@ aarch64_print_operand (char *buf, size_t size, bfd_vma pc,
       /* The optional-ness of <Xt> in e.g. IC <ic_op>{, <Xt>} is determined by
 	 the <ic_op>, therefore we we use opnd->present to override the
 	 generic optional-ness information.  */
-      if (opnd->type == AARCH64_OPND_Rt_SYS && !opnd->present)
-	break;
+      if (opnd->type == AARCH64_OPND_Rt_SYS)
+	{
+	  if (!opnd->present)
+	    break;
+	}
       /* Omit the operand, e.g. RET.  */
-      if (optional_operand_p (opcode, idx)
-	  && opnd->reg.regno == get_optional_operand_default_value (opcode))
+      else if (optional_operand_p (opcode, idx)
+	       && (opnd->reg.regno
+		   == get_optional_operand_default_value (opcode)))
 	break;
       assert (opnd->qualifier == AARCH64_OPND_QLF_W
 	      || opnd->qualifier == AARCH64_OPND_QLF_X);