AArch64: Update encodings for stg, st2g, stzg and st2zg.

This patch is part of a series of patches to introduce a few changes to the
Armv8.5-A Memory Tagging Extension. This patch updates the st*g instructions
to use a previously reserved field for a new register operand. Thus the
new versions of the instructions are as follows:

- STG Xt, [<Xn|SP>, #<simm>]
- STG Xt, [<Xn|SP>, #<simm>]!
- STG Xt, [<Xn|SP>], #<simm>
- STZG Xt, [<Xn|SP>, #<simm>]
- STZG Xt, [<Xn|SP>, #<simm>]!
- STZG Xt, [<Xn|SP>], #<simm>
- ST2G Xt, [<Xn|SP>, #<simm>]
- ST2G Xt, [<Xn|SP>, #<simm>]!
- ST2G Xt, [<Xn|SP>], #<simm>
- STZ2G Xt, [<Xn|SP>, #<simm>]
- STZ2G Xt, [<Xn|SP>, #<simm>]!
- STZ2G Xt, [<Xn|SP>], #<simm>

Committed on behalf of Sudakshina Das.

*** gas/ChangeLog ***

	* config/tc-aarch64.c (warn_unpredictable_ldst): Exempt
	stg, st2g, stzg and stz2g from Xt == Xn with writeback warning.
	* testsuite/gas/aarch64/armv8_5-a-memtag.d: Change tests for
	stg, stzg, st2g and stz2g.
	* testsuite/gas/aarch64/armv8_5-a-memtag.s: Likewise.
	* testsuite/gas/aarch64/illegal-memtag.l: Likewise.
	* testsuite/gas/aarch64/illegal-memtag.s: Likewise.

*** opcodes/ChangeLog ***

	* aarch64-tbl.h (QL_LDST_AT): Update macro.
	(aarch64_opcode): Change encoding for stg, stzg
	st2g and st2zg.
	* aarch64-asm-2.c: Regenerated.
	* aarch64-dis-2.c: Regenerated.
	* aarch64-opc-2.c: Regenerated.

(cherry picked from commit 69105ce4c42e5644ab92cb9b2765ff5ce6bf7b1b)

6 files changed, 112 insertions, 79 deletions

diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index 537f00ceb27..1acf6f671bd 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -6772,6 +6772,8 @@ warn_unpredictable_ldst (aarch64_instruction *instr, char *str)
 	   == AARCH64_OPND_CLASS_INT_REG)
 	  && opnds[0].reg.regno == opnds[1].addr.base_regno
 	  && opnds[1].addr.base_regno != REG_SP
+	  /* Exempt STG/STZG/ST2G/STZ2G.  */
+	  && !(opnds[1].type == AARCH64_OPND_ADDR_SIMM13)
 	  && opnds[1].addr.writeback)
 	as_warn (_("unpredictable transfer with writeback -- `%s'"), str);
       break;
diff --git a/gas/testsuite/gas/aarch64/armv8_5-a-memtag.d b/gas/testsuite/gas/aarch64/armv8_5-a-memtag.d
index 678fefce609..53a95fb302b 100644
--- a/gas/testsuite/gas/aarch64/armv8_5-a-memtag.d
+++ b/gas/testsuite/gas/aarch64/armv8_5-a-memtag.d
@@ -55,50 +55,66 @@ Disassembly of section \.text:
 .*:	badb037f 	cmpp	x27, x27
 .*:	bac003ff 	cmpp	sp, x0
 .*:	badf001f 	cmpp	x0, sp
-.*:	d920081f 	stg	\[x0\]
-.*:	d9200b7f 	stg	\[x27\]
-.*:	d93fb81f 	stg	\[x0, #-80\]
-.*:	d9200c1f 	stg	\[x0, #0\]!
-.*:	d920ac1f 	stg	\[x0, #160\]!
-.*:	d920041f 	stg	\[x0\], #0
-.*:	d93a641f 	stg	\[x0\], #-1440
-.*:	d92ffbff 	stg	\[sp, #4080\]
-.*:	d9300bff 	stg	\[sp, #-4096\]
-.*:	d92fffff 	stg	\[sp, #4080\]!
-.*:	d93007ff 	stg	\[sp\], #-4096
-.*:	d960081f 	stzg	\[x0\]
-.*:	d9600b7f 	stzg	\[x27\]
-.*:	d97fb81f 	stzg	\[x0, #-80\]
-.*:	d9600c1f 	stzg	\[x0, #0\]!
-.*:	d960ac1f 	stzg	\[x0, #160\]!
-.*:	d960041f 	stzg	\[x0\], #0
-.*:	d97a641f 	stzg	\[x0\], #-1440
-.*:	d96ffbff 	stzg	\[sp, #4080\]
-.*:	d9700bff 	stzg	\[sp, #-4096\]
-.*:	d96fffff 	stzg	\[sp, #4080\]!
-.*:	d97007ff 	stzg	\[sp\], #-4096
-.*:	d9a0081f 	st2g	\[x0\]
-.*:	d9a00b7f 	st2g	\[x27\]
-.*:	d9bfb81f 	st2g	\[x0, #-80\]
-.*:	d9a00c1f 	st2g	\[x0, #0\]!
-.*:	d9a0ac1f 	st2g	\[x0, #160\]!
-.*:	d9a0041f 	st2g	\[x0\], #0
-.*:	d9ba641f 	st2g	\[x0\], #-1440
-.*:	d9affbff 	st2g	\[sp, #4080\]
-.*:	d9b00bff 	st2g	\[sp, #-4096\]
-.*:	d9afffff 	st2g	\[sp, #4080\]!
-.*:	d9b007ff 	st2g	\[sp\], #-4096
-.*:	d9e0081f 	stz2g	\[x0\]
-.*:	d9e00b7f 	stz2g	\[x27\]
-.*:	d9ffb81f 	stz2g	\[x0, #-80\]
-.*:	d9e00c1f 	stz2g	\[x0, #0\]!
-.*:	d9e0ac1f 	stz2g	\[x0, #160\]!
-.*:	d9e0041f 	stz2g	\[x0\], #0
-.*:	d9fa641f 	stz2g	\[x0\], #-1440
-.*:	d9effbff 	stz2g	\[sp, #4080\]
-.*:	d9f00bff 	stz2g	\[sp, #-4096\]
-.*:	d9efffff 	stz2g	\[sp, #4080\]!
-.*:	d9f007ff 	stz2g	\[sp\], #-4096
+.*:	d9200800 	stg	x0, \[x0\]
+.*:	d9200b60 	stg	x0, \[x27\]
+.*:	d920081f 	stg	xzr, \[x0\]
+.*:	d93fb81b 	stg	x27, \[x0, #-80\]
+.*:	d9200c00 	stg	x0, \[x0, #0\]!
+.*:	d9200c1f 	stg	xzr, \[x0, #0\]!
+.*:	d920ac1b 	stg	x27, \[x0, #160\]!
+.*:	d9200400 	stg	x0, \[x0\], #0
+.*:	d920041f 	stg	xzr, \[x0\], #0
+.*:	d93a641b 	stg	x27, \[x0\], #-1440
+.*:	d92ffbe0 	stg	x0, \[sp, #4080\]
+.*:	d92ffbff 	stg	xzr, \[sp, #4080\]
+.*:	d9300bfb 	stg	x27, \[sp, #-4096\]
+.*:	d92fffe0 	stg	x0, \[sp, #4080\]!
+.*:	d93007ff 	stg	xzr, \[sp\], #-4096
+.*:	d9600800 	stzg	x0, \[x0\]
+.*:	d9600b60 	stzg	x0, \[x27\]
+.*:	d960081f 	stzg	xzr, \[x0\]
+.*:	d97fb81b 	stzg	x27, \[x0, #-80\]
+.*:	d9600c00 	stzg	x0, \[x0, #0\]!
+.*:	d9600c1f 	stzg	xzr, \[x0, #0\]!
+.*:	d960ac1b 	stzg	x27, \[x0, #160\]!
+.*:	d9600400 	stzg	x0, \[x0\], #0
+.*:	d960041f 	stzg	xzr, \[x0\], #0
+.*:	d97a641b 	stzg	x27, \[x0\], #-1440
+.*:	d96ffbe0 	stzg	x0, \[sp, #4080\]
+.*:	d96ffbff 	stzg	xzr, \[sp, #4080\]
+.*:	d9700bfb 	stzg	x27, \[sp, #-4096\]
+.*:	d96fffe0 	stzg	x0, \[sp, #4080\]!
+.*:	d97007ff 	stzg	xzr, \[sp\], #-4096
+.*:	d9a00800 	st2g	x0, \[x0\]
+.*:	d9a00b60 	st2g	x0, \[x27\]
+.*:	d9a0081f 	st2g	xzr, \[x0\]
+.*:	d9bfb81b 	st2g	x27, \[x0, #-80\]
+.*:	d9a00c00 	st2g	x0, \[x0, #0\]!
+.*:	d9a00c1f 	st2g	xzr, \[x0, #0\]!
+.*:	d9a0ac1b 	st2g	x27, \[x0, #160\]!
+.*:	d9a00400 	st2g	x0, \[x0\], #0
+.*:	d9a0041f 	st2g	xzr, \[x0\], #0
+.*:	d9ba641b 	st2g	x27, \[x0\], #-1440
+.*:	d9affbe0 	st2g	x0, \[sp, #4080\]
+.*:	d9affbff 	st2g	xzr, \[sp, #4080\]
+.*:	d9b00bfb 	st2g	x27, \[sp, #-4096\]
+.*:	d9afffe0 	st2g	x0, \[sp, #4080\]!
+.*:	d9b007ff 	st2g	xzr, \[sp\], #-4096
+.*:	d9e00800 	stz2g	x0, \[x0\]
+.*:	d9e00b60 	stz2g	x0, \[x27\]
+.*:	d9e0081f 	stz2g	xzr, \[x0\]
+.*:	d9ffb81b 	stz2g	x27, \[x0, #-80\]
+.*:	d9e00c00 	stz2g	x0, \[x0, #0\]!
+.*:	d9e00c1f 	stz2g	xzr, \[x0, #0\]!
+.*:	d9e0ac1b 	stz2g	x27, \[x0, #160\]!
+.*:	d9e00400 	stz2g	x0, \[x0\], #0
+.*:	d9e0041f 	stz2g	xzr, \[x0\], #0
+.*:	d9fa641b 	stz2g	x27, \[x0\], #-1440
+.*:	d9effbe0 	stz2g	x0, \[sp, #4080\]
+.*:	d9effbff 	stz2g	xzr, \[sp, #4080\]
+.*:	d9f00bfb 	stz2g	x27, \[sp, #-4096\]
+.*:	d9efffe0 	stz2g	x0, \[sp, #4080\]!
+.*:	d9f007ff 	stz2g	xzr, \[sp\], #-4096
 .*:	69000000 	stgp	x0, x0, \[x0\]
 .*:	69006c00 	stgp	x0, x27, \[x0\]
 .*:	6900001b 	stgp	x27, x0, \[x0\]
diff --git a/gas/testsuite/gas/aarch64/armv8_5-a-memtag.s b/gas/testsuite/gas/aarch64/armv8_5-a-memtag.s
index b8cab9f0eff..2ca1a682018 100644
--- a/gas/testsuite/gas/aarch64/armv8_5-a-memtag.s
+++ b/gas/testsuite/gas/aarch64/armv8_5-a-memtag.s
@@ -17,17 +17,21 @@ func:
 	.endm
 
 	.macro expand_stg op
-	\op [x0, #0]
-	\op [x27, #0]
-	\op [x0, #-80]
-	\op [x0, #0]!
-	\op [x0, #160]!
-	\op [x0], #0
-	\op [x0], #-1440
-	\op [sp, #4080]
-	\op [sp, #-4096]
-	\op [sp, #4080]!
-	\op [sp], #-4096
+	\op x0, [x0, #0]
+	\op x0, [x27, #0]
+	\op xzr, [x0, #0]
+	\op x27, [x0, #-80]
+	\op x0, [x0, #0]!
+	\op xzr, [x0, #0]!
+	\op x27, [x0, #160]!
+	\op x0, [x0], #0
+	\op xzr, [x0], #0
+	\op x27, [x0], #-1440
+	\op x0, [sp, #4080]
+	\op xzr, [sp, #4080]
+	\op x27, [sp, #-4096]
+	\op x0, [sp, #4080]!
+	\op xzr, [sp], #-4096
 	.endm
 
 	.macro expand_ldg_bulk op
diff --git a/gas/testsuite/gas/aarch64/illegal-memtag.l b/gas/testsuite/gas/aarch64/illegal-memtag.l
index 2505ffe79f8..aa79aacc18d 100644
--- a/gas/testsuite/gas/aarch64/illegal-memtag.l
+++ b/gas/testsuite/gas/aarch64/illegal-memtag.l
@@ -4,9 +4,9 @@
 [^:]*:[0-9]+: Error: immediate value out of range 0 to 1008 at operand 3 -- `subg x1,x2,-16,#0x3'
 [^:]*:[0-9]+: Error: immediate value out of range 0 to 15 at operand 4 -- `addg x1,x2,#0x3f0,#0x10'
 [^:]*:[0-9]+: Error: immediate value out of range 0 to 15 at operand 4 -- `subg x1,x2,#0x3f0,-4'
-[^:]*:[0-9]+: Error: immediate value must be a multiple of 16 at operand 1 -- `stg \[x1,#15\]'
-[^:]*:[0-9]+: Error: immediate offset out of range -4096 to 4080 at operand 1 -- `stzg \[x1,#-4097]!'
-[^:]*:[0-9]+: Error: immediate offset out of range -4096 to 4080 at operand 1 -- `st2g \[x1],#4096'
+[^:]*:[0-9]+: Error: immediate value must be a multiple of 16 at operand 2 -- `stg x2,\[x1,#15\]'
+[^:]*:[0-9]+: Error: immediate offset out of range -4096 to 4080 at operand 2 -- `stzg x2,\[x1,#-4097\]!'
+[^:]*:[0-9]+: Error: immediate offset out of range -4096 to 4080 at operand 2 -- `st2g x2,\[x1\],#4096'
 [^:]*:[0-9]+: Error: immediate value must be a multiple of 16 at operand 2 -- `ldg x1,\[x2,#33\]'
 [^:]*:[0-9]+: Error: immediate offset out of range -4096 to 4080 at operand 2 -- `ldg x1,\[x2,#4112\]'
 [^:]*:[0-9]+: Error: immediate offset out of range -1024 to 1008 at operand 3 -- `stgp x1,x2,\[x3,#1009\]'
@@ -30,10 +30,14 @@
 [^:]*:[0-9]+: Error: operand 3 must be an integer or stack pointer register -- `subps x1,x2,xzr'
 [^:]*:[0-9]+: Error: operand 1 must be an integer or stack pointer register -- `cmpp xzr,x2'
 [^:]*:[0-9]+: Error: operand 2 must be an integer or stack pointer register -- `cmpp x2,xzr'
-[^:]*:[0-9]+: Error: 64-bit integer or SP register expected at operand 1 -- `stg \[xzr,#0\]'
-[^:]*:[0-9]+: Error: 64-bit integer or SP register expected at operand 1 -- `st2g \[xzr,#0]!'
-[^:]*:[0-9]+: Error: 64-bit integer or SP register expected at operand 1 -- `stzg \[xzr],#0'
-[^:]*:[0-9]+: Error: 64-bit integer or SP register expected at operand 1 -- `stz2g \[xzr,#0\]'
+[^:]*:[0-9]+: Error: 64-bit integer or SP register expected at operand 2 -- `stg x2,\[xzr,#0\]'
+[^:]*:[0-9]+: Error: 64-bit integer or SP register expected at operand 2 -- `st2g x2,\[xzr,#0\]!'
+[^:]*:[0-9]+: Error: 64-bit integer or SP register expected at operand 2 -- `stzg x2,\[xzr\],#0'
+[^:]*:[0-9]+: Error: 64-bit integer or SP register expected at operand 2 -- `stz2g x2,\[xzr,#0\]'
+[^:]*:[0-9]+: Error: operand 1 must be an integer register -- `stg sp,\[x2,#0\]'
+[^:]*:[0-9]+: Error: operand 1 must be an integer register -- `st2g sp,\[x2,#0\]!'
+[^:]*:[0-9]+: Error: operand 1 must be an integer register -- `stzg sp,\[x2\],#0'
+[^:]*:[0-9]+: Error: operand 1 must be an integer register -- `stz2g sp,\[x2,#0\]'
 [^:]*:[0-9]+: Error: operand 1 must be an integer register -- `stgp sp,x2,\[x3\]'
 [^:]*:[0-9]+: Error: operand 2 must be an integer register -- `stgp x1,sp,\[x3\]'
 [^:]*:[0-9]+: Error: 64-bit integer or SP register expected at operand 3 -- `stgp x0,x0,\[xzr\]'
diff --git a/gas/testsuite/gas/aarch64/illegal-memtag.s b/gas/testsuite/gas/aarch64/illegal-memtag.s
index 2a45e164af3..9c9c48b3bde 100644
--- a/gas/testsuite/gas/aarch64/illegal-memtag.s
+++ b/gas/testsuite/gas/aarch64/illegal-memtag.s
@@ -9,9 +9,9 @@ func:
 	subg x1, x2, #0x3f0, -4
 
 	# STG/STZG/ST2G/LDG : Fail imm
-	stg [x1, #15]
-	stzg [x1, #-4097]!
-	st2g [x1], #4096
+	stg x2, [x1, #15]
+	stzg x2, [x1, #-4097]!
+	st2g x2, [x1], #4096
 	ldg x1, [x2, #33]
 	ldg x1, [x2, #4112]
 
@@ -41,10 +41,14 @@ func:
 	subps x1, x2, xzr
 	cmpp xzr, x2
 	cmpp x2, xzr
-	stg [xzr, #0]
-	st2g [xzr, #0]!
-	stzg [xzr], #0
-	stz2g [xzr, #0]
+	stg x2, [xzr, #0]
+	st2g x2, [xzr, #0]!
+	stzg x2, [xzr], #0
+	stz2g x2, [xzr, #0]
+	stg sp, [x2, #0]
+	st2g sp, [x2, #0]!
+	stzg sp, [x2], #0
+	stz2g sp, [x2, #0]
 	stgp sp, x2, [x3]
 	stgp x1, sp, [x3]
 	stgp x0, x0, [xzr]
@@ -52,3 +56,6 @@ func:
 	ldg x0, [xzr, #16]
 	stzgm x0, [xzr]
 	stzgm sp, [x3]
+	# Xt == Xn with writeback should not complain
+	st2g x2, [x2, #0]!
+	stzg x2, [x2], #0
diff --git a/opcodes/aarch64-tbl.h b/opcodes/aarch64-tbl.h
index 277293b40c9..ac05aae582c 100644
--- a/opcodes/aarch64-tbl.h
+++ b/opcodes/aarch64-tbl.h
@@ -125,10 +125,10 @@
   QLF1(X),			\
 }
 
-/* e.g. STG [<Xn|SP>, #<imm9>].  */
+/* e.g. STG Xt, [<Xn|SP>, #<imm9>].  */
 #define QL_LDST_AT		\
 {				\
-  QLF1(imm_tag),		\
+  QLF2(X, imm_tag),		\
 }
 
 /* e.g. RBIT <Wd>, <Wn>.  */
@@ -3237,14 +3237,14 @@ struct aarch64_opcode aarch64_opcode_table[] =
   CORE_INSN ("ldr", 0xb8400400, 0xbfe00400, ldst_imm9, 0, OP2 (Rt, ADDR_SIMM9), QL_LDST_R, F_GPRSIZE_IN_Q),
   CORE_INSN ("ldrsw", 0xb8800400, 0xffe00400, ldst_imm9, 0, OP2 (Rt, ADDR_SIMM9), QL_LDST_X32, 0),
   /* Load/store Allocation Tag instructions.  */
-  MEMTAG_INSN ("stg",  0xd920081f, 0xffe00c1f, ldst_unscaled, OP1 (ADDR_SIMM13), QL_LDST_AT, 0),
-  MEMTAG_INSN ("stzg", 0xd960081f, 0xffe00c1f, ldst_unscaled, OP1 (ADDR_SIMM13), QL_LDST_AT, 0),
-  MEMTAG_INSN ("st2g", 0xd9a0081f, 0xffe00c1f, ldst_unscaled, OP1 (ADDR_SIMM13), QL_LDST_AT, 0),
-  MEMTAG_INSN ("stz2g",0xd9e0081f, 0xffe00c1f, ldst_unscaled, OP1 (ADDR_SIMM13), QL_LDST_AT, 0),
-  MEMTAG_INSN ("stg",  0xd920041f, 0xffe0041f, ldst_imm9, OP1 (ADDR_SIMM13), QL_LDST_AT, 0),
-  MEMTAG_INSN ("stzg", 0xd960041f, 0xffe0041f, ldst_imm9, OP1 (ADDR_SIMM13), QL_LDST_AT, 0),
-  MEMTAG_INSN ("st2g", 0xd9a0041f, 0xffe0041f, ldst_imm9, OP1 (ADDR_SIMM13), QL_LDST_AT, 0),
-  MEMTAG_INSN ("stz2g",0xd9e0041f, 0xffe0041f, ldst_imm9, OP1 (ADDR_SIMM13), QL_LDST_AT, 0),
+  MEMTAG_INSN ("stg",  0xd9200800, 0xffe00c00, ldst_unscaled, OP2 (Rt, ADDR_SIMM13), QL_LDST_AT, 0),
+  MEMTAG_INSN ("stzg", 0xd9600800, 0xffe00c00, ldst_unscaled, OP2 (Rt, ADDR_SIMM13), QL_LDST_AT, 0),
+  MEMTAG_INSN ("st2g", 0xd9a00800, 0xffe00c00, ldst_unscaled, OP2 (Rt, ADDR_SIMM13), QL_LDST_AT, 0),
+  MEMTAG_INSN ("stz2g",0xd9e00800, 0xffe00c00, ldst_unscaled, OP2 (Rt, ADDR_SIMM13), QL_LDST_AT, 0),
+  MEMTAG_INSN ("stg",  0xd9200400, 0xffe00400, ldst_imm9, OP2 (Rt, ADDR_SIMM13), QL_LDST_AT, 0),
+  MEMTAG_INSN ("stzg", 0xd9600400, 0xffe00400, ldst_imm9, OP2 (Rt, ADDR_SIMM13), QL_LDST_AT, 0),
+  MEMTAG_INSN ("st2g", 0xd9a00400, 0xffe00400, ldst_imm9, OP2 (Rt, ADDR_SIMM13), QL_LDST_AT, 0),
+  MEMTAG_INSN ("stz2g",0xd9e00400, 0xffe00400, ldst_imm9, OP2 (Rt, ADDR_SIMM13), QL_LDST_AT, 0),
   /* Load/store register (unsigned immediate).  */
   CORE_INSN ("strb", 0x39000000, 0xffc00000, ldst_pos, OP_STRB_POS, OP2 (Rt, ADDR_UIMM12), QL_LDST_W8, 0),
   CORE_INSN ("ldrb", 0x39400000, 0xffc00000, ldst_pos, OP_LDRB_POS, OP2 (Rt, ADDR_UIMM12), QL_LDST_W8, 0),