[llvm] [AArch64] Ensure APAS instruction passes register parameter (PR #121928)

[Jonathan Thackray via llvm-commits]

https://github.com/jthackray created https://github.com/llvm/llvm-project/pull/121928

In PR #112341, the `APAS` instruction was added as part of the Armv9.6-A specification, but it didn't take the Xt register parameter. This change fixes this.

>From 2b0fda5f71eeb2380659f62a21544da72358efb3 Mon Sep 17 00:00:00 2001
From: Jonathan Thackray <jonathan.thackray at arm.com>
Date: Mon, 6 Jan 2025 19:42:34 +0000
Subject: [PATCH] [AArch64] Ensure APAS instruction passes register parameter

In PR #112341, the `APAS` instruction was added as part of the
Armv9.6-A specification, but it didn't take the Xt register
parameter. This change fixes this.
---
 llvm/lib/Target/AArch64/AArch64InstrFormats.td       |  2 ++
 llvm/test/MC/AArch64/armv9.6a-rme-gpc3.s             | 10 +++++++++-
 .../MC/Disassembler/AArch64/armv9.6a-rme-gpc3.txt    | 12 ++++++++++--
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/Target/AArch64/AArch64InstrFormats.td b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
index 47c4c6c39565f4..b6fabdb7db59d2 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrFormats.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
@@ -1804,7 +1804,9 @@ class TMSystemException<bits<3> op1, string asm, list<dag> pattern>
 }
 
 class APASI : SimpleSystemI<0, (ins GPR64:$Xt), "apas", "\t$Xt">, Sched<[]> {
+  bits<5> Xt;
   let Inst{20-5} = 0b0111001110000000;
+  let Inst{4-0} = Xt;
   let DecoderNamespace = "APAS";
 }
 
diff --git a/llvm/test/MC/AArch64/armv9.6a-rme-gpc3.s b/llvm/test/MC/AArch64/armv9.6a-rme-gpc3.s
index baf05f10b9a1e3..093101b6cd8127 100644
--- a/llvm/test/MC/AArch64/armv9.6a-rme-gpc3.s
+++ b/llvm/test/MC/AArch64/armv9.6a-rme-gpc3.s
@@ -2,10 +2,18 @@
 // RUN: llvm-mc -triple aarch64 -show-encoding %s  | FileCheck %s
 .func:
   apas x0
+  apas x1
+  apas x2
+  apas x17
+  apas x30
   mrs x3, GPCBW_EL3
   msr GPCBW_EL3, x4
 
 # CHECK:      .func:
-# CHECK-NEXT: 	apas	x0                              // encoding: [0x1f,0x70,0x0e,0xd5]
+# CHECK-NEXT:	apas    x0                              // encoding: [0x00,0x70,0x0e,0xd5]
+# CHECK-NEXT:	apas    x1                              // encoding: [0x01,0x70,0x0e,0xd5]
+# CHECK-NEXT:	apas    x2                              // encoding: [0x02,0x70,0x0e,0xd5]
+# CHECK-NEXT:	apas    x17                             // encoding: [0x11,0x70,0x0e,0xd5]
+# CHECK-NEXT:	apas    x30                             // encoding: [0x1e,0x70,0x0e,0xd5]
 # CHECK-NEXT: 	mrs	x3, GPCBW_EL3                   // encoding: [0xa3,0x21,0x3e,0xd5]
 # CHECK-NEXT: 	msr	GPCBW_EL3, x4                   // encoding: [0xa4,0x21,0x1e,0xd5]
diff --git a/llvm/test/MC/Disassembler/AArch64/armv9.6a-rme-gpc3.txt b/llvm/test/MC/Disassembler/AArch64/armv9.6a-rme-gpc3.txt
index c5d074bf0394f1..d198771c341b9e 100644
--- a/llvm/test/MC/Disassembler/AArch64/armv9.6a-rme-gpc3.txt
+++ b/llvm/test/MC/Disassembler/AArch64/armv9.6a-rme-gpc3.txt
@@ -1,10 +1,18 @@
 # NOTE: Assertions have been autogenerated by utils/update_mca_test_checks.py
 # RUN: llvm-mc -triple aarch64 -disassemble %s  | FileCheck %s
 
-[0x1f,0x70,0x0e,0xd5]
+[0x00,0x70,0x0e,0xd5]
+[0x01,0x70,0x0e,0xd5]
+[0x02,0x70,0x0e,0xd5]
+[0x11,0x70,0x0e,0xd5]
+[0x1e,0x70,0x0e,0xd5]
 [0xa3,0x21,0x3e,0xd5]
 [0xa4,0x21,0x1e,0xd5]
 
-# CHECK:      	sys	#6, c7, c0, #0
+# CHECK:      	sys	#6, c7, c0, #0, x0
+# CHECK-NEXT: 	sys	#6, c7, c0, #0, x1
+# CHECK-NEXT: 	sys	#6, c7, c0, #0, x2
+# CHECK-NEXT: 	sys	#6, c7, c0, #0, x17
+# CHECK-NEXT: 	sys	#6, c7, c0, #0, x30
 # CHECK-NEXT: 	mrs	x3, GPCBW_EL3
 # CHECK-NEXT: 	msr	GPCBW_EL3, x4