[llvm] [LLVM][AArch64]CFINV - Add UNPREDICTABLE behaviour if CRm is not zero (PR #140593)

[via llvm-commits]

https://github.com/CarolineConcatto updated https://github.com/llvm/llvm-project/pull/140593

>From cd5db8e1407e47f9a4bb7b95b846c0410cf1acdf Mon Sep 17 00:00:00 2001
From: CarolineConcatto <caroline.concatto at arm.com>
Date: Mon, 19 May 2025 18:37:40 +0000
Subject: [PATCH] [LLVM][AArch64]CFINV - Add UNPREDICTABLE behaviour if CRm is
 not zero

Now CFINV follows AXFLAGS behaviour for CRm.

It looks like (0) in the instruction encoding means that the behaviour is
UNPREDICTABLE if that bit is not zero.
---
 llvm/lib/Target/AArch64/AArch64InstrInfo.td         | 1 +
 llvm/test/MC/Disassembler/AArch64/armv8.4a-flag.txt | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 010c7c391527f..22ecf99b12de6 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -2096,6 +2096,7 @@ def FJCVTZS  : BaseFPToIntegerUnscaled<0b01, 0b11, 0b110, FPR64, GPR32,
 let Predicates = [HasFlagM], Defs = [NZCV], Uses = [NZCV] in {
 def CFINV : SimpleSystemI<0, (ins), "cfinv", "">, Sched<[WriteSys]> {
   let Inst{20-5} = 0b0000001000000000;
+  let Unpredictable{11-8} = 0b1111;
 }
 def SETF8  : BaseFlagManipulation<0, 0, (ins GPR32:$Rn), "setf8", "{\t$Rn}">;
 def SETF16 : BaseFlagManipulation<0, 1, (ins GPR32:$Rn), "setf16", "{\t$Rn}">;
diff --git a/llvm/test/MC/Disassembler/AArch64/armv8.4a-flag.txt b/llvm/test/MC/Disassembler/AArch64/armv8.4a-flag.txt
index c29109d578f2c..1f12c2cca0de1 100644
--- a/llvm/test/MC/Disassembler/AArch64/armv8.4a-flag.txt
+++ b/llvm/test/MC/Disassembler/AArch64/armv8.4a-flag.txt
@@ -2,10 +2,12 @@
 # RUN: llvm-mc -triple aarch64-none-linux-gnu -mattr=+v8r --disassemble < %s | FileCheck %s
 
 [0x1f,0x40,0x00,0xd5]
+[0x1f,0x4f,0x00,0xd5]
 [0x2d,0x08,0x00,0x3a]
 [0x2d,0x48,0x00,0x3a]
 [0x2f,0x84,0x1f,0xba]
 
+#CHECK:  cfinv
 #CHECK:  cfinv
 #CHECK:  setf8  w1
 #CHECK:  setf16  w1