aarch64: rcpc3: Add integer load/store insns

Along with the relevant unit tests and updates to the existing
regression tests, this adds support for the following novel rcpc3
insns:

  LDIAPP <Wt1>, <Wt2>, [<Xn|SP>]
  LDIAPP <Wt1>, <Wt2>, [<Xn|SP>], #8
  LDIAPP <Xt1>, <Xt2>, [<Xn|SP>]
  LDIAPP <Xt1>, <Xt2>, [<Xn|SP>], #16

  STILP <Wt1>, <Wt2>, [<Xn|SP>]
  STILP <Wt1>, <Wt2>, [<Xn|SP>, #-8]!
  STILP <Xt1>, <Xt2>, [<Xn|SP>]
  STILP <Xt1>, <Xt2>, [<Xn|SP>, #-16]!

  LDAPR <Wt>, [<Xn|SP>], #4
  LDAPR <Xt>, [<Xn|SP>], #8

  STLR <Wt>, [<Xn|SP>, #-4]!
  STLR <Xt>, [<Xn|SP>, #-8]!

gas/testsuite/gas/aarch64/illegal-ldapr.l

@@ -22,7 +22,7 @@
 [^:]+:23:  Info: macro .*
 [^:]+:6: Error: the optional immediate offset can only be 0 at operand 2 -- `ldapr w1,\[x7,#8\]'
 [^:]+:23:  Info: macro .*
-[^:]+:7: Error: invalid addressing mode at operand 2 -- `ldapr w1,\[x7,#8\]!'
+[^:]+:7: Error: unexpected address writeback at operand 2 -- `ldapr w1,\[x7,#8\]!'
 [^:]+:23:  Info: macro .*
-[^:]+:8: Error: invalid addressing mode at operand 2 -- `ldapr w1,\[x7\],#8'
+[^:]+:8: Error: invalid increment amount at operand 2 -- `ldapr w1,\[x7\],#8'
 [^:]+:23:  Info: macro .*

gas/testsuite/gas/aarch64/rcpc3-fail.d

@@ -0,0 +1,3 @@
+#name: RCPC3 GPR load/store illegal
+#as: -march=armv8.3-a+rcpc3 -mno-verbose-error
+#error_output: rcpc3-fail.l

gas/testsuite/gas/aarch64/rcpc3-fail.l

@@ -0,0 +1,9 @@
+[^:]+: Assembler messages:
+[^:]+:3: Error: operand 3 must be an address with post-incrementing by ammount of loaded bytes -- `ldiapp w0,w1,\[x3,#8\]'
+[^:]+:4: Error: operand 3 must be an address with post-incrementing by ammount of loaded bytes -- `ldiapp x0,x1,\[x3,#16\]'
+[^:]+:6: Error: operand 3 must be an address with pre-incrementing with write-back by ammount of stored bytes -- `stilp w0,w1,\[x3,#8\]'
+[^:]+:7: Error: operand 3 must be an address with pre-incrementing with write-back by ammount of stored bytes -- `stilp x0,x1,\[x3,#16\]'
+[^:]+:9: Error: invalid addressing mode at operand 3 -- `stilp w0,w1,\[x3\],#8'
+[^:]+:10: Error: invalid addressing mode at operand 3 -- `stilp x0,x1,\[x3\],#16'
+[^:]+:12: Error: invalid addressing mode at operand 3 -- `ldiapp w0,w1,\[x3,#-8\]!'
+[^:]+:13: Error: invalid addressing mode at operand 3 -- `ldiapp x0,x1,\[x3,#-16\]!'

gas/testsuite/gas/aarch64/rcpc3-fail.s

@@ -0,0 +1,13 @@
+.text
+
+	ldiapp w0, w1, [x3, #8]
+	ldiapp x0, x1, [x3, #16]
+
+	stilp w0, w1, [x3, #8]
+	stilp x0, x1, [x3, #16]
+
+	stilp w0, w1, [x3], #8
+	stilp x0, x1, [x3], #16
+
+	ldiapp w0, w1, [x3, #-8]!
+	ldiapp x0, x1, [x3, #-16]!

gas/testsuite/gas/aarch64/rcpc3.d

@@ -0,0 +1,21 @@
+#name: RCPC3 GPR load/store
+#as: -march=armv8.2-a+rcpc3
+#objdump: -dr
+
+.*:     file format .*
+
+Disassembly of section \.text:
+
+0+ <.*>:
+   0:	d9411860 	ldiapp	x0, x1, \[x3\]
+   4:	99411860 	ldiapp	w0, w1, \[x3\]
+   8:	d9410860 	ldiapp	x0, x1, \[x3\], #16
+   c:	99410860 	ldiapp	w0, w1, \[x3\], #8
+  10:	d9011860 	stilp	x0, x1, \[x3\]
+  14:	99011860 	stilp	w0, w1, \[x3\]
+  18:	d9010860 	stilp	x0, x1, \[x3, #-16\]!
+  1c:	99010860 	stilp	w0, w1, \[x3, #-8\]!
+  20:	99c00841 	ldapr	w1, \[x2\], #4
+  24:	d9c00841 	ldapr	x1, \[x2\], #8
+  28:	99800841 	stlr	w1, \[x2, #-4\]!
+  2c:	d9800841 	stlr	x1, \[x2, #-8\]!

gas/testsuite/gas/aarch64/rcpc3.s

@@ -0,0 +1,17 @@
+.text
+
+	ldiapp x0, x1, [x3]
+	ldiapp w0, w1, [x3]
+	ldiapp x0, x1, [x3], #16
+	ldiapp w0, w1, [x3], #8
+
+	stilp x0, x1, [x3]
+	stilp w0, w1, [x3]
+	stilp x0, x1, [x3, #-16]!
+	stilp w0, w1, [x3, #-8]!
+
+	ldapr w1, [x2], #4
+	ldapr x1, [x2], #8
+
+	stlr w1, [x2, #-4]!
+	stlr x1, [x2, #-8]!

include/opcode/aarch64.h

@@ -1013,6 +1013,7 @@ enum aarch64_insn_class
   the,
   sve2_urqvs,
   sve_index1,
+  rcpc3
 };
 
 /* Opcode enumerators.  */

opcodes/aarch64-tbl.h

@@ -4216,6 +4216,11 @@ const struct aarch64_opcode aarch64_opcode_table[] =
   _LSE128_INSN ("swppa", 0x19a08000, 0xffe0fc00, lse128_atomic, OP3 (LSE128_Rt, LSE128_Rt2, ADDR_SIMPLE), QL_X2NIL, 0),
   _LSE128_INSN ("swppal", 0x19e08000, 0xffe0fc00, lse128_atomic, OP3 (LSE128_Rt, LSE128_Rt2, ADDR_SIMPLE), QL_X2NIL, 0),
   _LSE128_INSN ("swppl", 0x19608000, 0xffe0fc00, lse128_atomic, OP3 (LSE128_Rt, LSE128_Rt2, ADDR_SIMPLE), QL_X2NIL, 0),
+  /* RCPC3 extension.  */
+  RCPC3_INSN ("ldiapp", 0x19400800, 0x3fe0ec00, rcpc3, OP3 (Rt, Rs, RCPC3_ADDR_OPT_POSTIND), QL_R2NIL, F_RCPC3_SIZE),
+  RCPC3_INSN ("stilp",  0x19000800, 0x3fe0ec00, rcpc3, OP3 (Rt, Rs, RCPC3_ADDR_OPT_PREIND_WB), QL_R2NIL, F_RCPC3_SIZE),
+  RCPC3_INSN ("ldapr", 0x19c00800, 0x3ffffc00, rcpc3, OP2 (Rt, RCPC3_ADDR_POSTIND), QL_R1NIL, F_RCPC3_SIZE),
+  RCPC3_INSN ("stlr", 0x19800800, 0x3ffffc00, rcpc3, OP2 (Rt, RCPC3_ADDR_PREIND_WB), QL_R1NIL, F_RCPC3_SIZE),
   /* Move wide (immediate).  */
   CORE_INSN ("movn", 0x12800000, 0x7f800000, movewide, OP_MOVN, OP2 (Rd, HALF), QL_DST_R, F_SF | F_HAS_ALIAS),
   CORE_INSN ("mov",  0x12800000, 0x7f800000, movewide, OP_MOV_IMM_WIDEN, OP2 (Rd, IMM_MOV), QL_DST_R, F_SF | F_ALIAS | F_CONV),