[llvm-branch-commits] [clang] [llvm] [AArch64][llvm] Armv9.8-A: Add support for FEAT_CFLT (Conditional Fault instructions) (PR #229362)

Jonathan Thackray via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Fri Oct 9 03:13:01 PDT 2026


https://github.com/jthackray updated https://github.com/llvm/llvm-project/pull/229362

>From 7b29944f15b252eaef57657a75a6e8cb1afc981a Mon Sep 17 00:00:00 2001
From: Jonathan Thackray <jonathan.thackray at arm.com>
Date: Tue, 6 Oct 2026 21:45:34 +0100
Subject: [PATCH 1/2] [AArch64][llvm] Armv9.8-A: Add support for FEAT_CFLT
 (Conditional Fault instructions)

Add support for FEAT_CFLT (Conditional Fault instructions), which
are optional from Armv9.7 onwards:
```
   cflteq, cfltne,
   cfltgt, cfltlt,
   cfltge, cfltle,
   cflthi, cfltlo,
   cflths, cfltls,
   cfltz,  cfltnz,
   tfltz,  tfltnz,
   flt.ne, flt.eq,
   flt.mi, flt.pl,
   flt.vs, flt.vc,
   flt.hi, flt.ls,
   flt.ge, flt.lt,
   flt.gt, flt.le,
   flt.al, flt.nv,
   flt.cs, flt.cc,
   flt.hs, flt.lo
```

Change-Id: I2bf0d806907158e804ff6610053aec8656ad6b92
---
 clang/test/Driver/aarch64-v98a.c              |   4 +
 .../print-supported-extensions-aarch64.c      |   1 +
 llvm/lib/Target/AArch64/AArch64Features.td    |   3 +
 .../lib/Target/AArch64/AArch64InstrFormats.td | 140 ++++++++
 llvm/lib/Target/AArch64/AArch64InstrInfo.td   |  49 +++
 .../AArch64/AsmParser/AArch64AsmParser.cpp    |  45 ++-
 .../Disassembler/AArch64Disassembler.cpp      |   7 +
 .../MC/AArch64/armv9.8a-cflt-diagnostics.s    |  89 +++++
 llvm/test/MC/AArch64/armv9.8a-cflt.s          | 329 ++++++++++++++++++
 .../test/MC/AArch64/directive-arch-negative.s |   6 +
 llvm/test/MC/AArch64/directive-arch.s         |   4 +
 .../directive-arch_extension-negative.s       |   6 +
 .../MC/AArch64/directive-arch_extension.s     |   4 +
 .../TargetParser/TargetParserTest.cpp         |   3 +
 14 files changed, 679 insertions(+), 11 deletions(-)
 create mode 100644 llvm/test/MC/AArch64/armv9.8a-cflt-diagnostics.s
 create mode 100644 llvm/test/MC/AArch64/armv9.8a-cflt.s

diff --git a/clang/test/Driver/aarch64-v98a.c b/clang/test/Driver/aarch64-v98a.c
index b578c577d00a17..8427b2b4aa2539 100644
--- a/clang/test/Driver/aarch64-v98a.c
+++ b/clang/test/Driver/aarch64-v98a.c
@@ -17,3 +17,7 @@
 // GENERICV98A-BE: "-cc1"{{.*}} "-triple" "aarch64_be{{.*}}" "-target-cpu" "generic" "-target-feature" "+v9.8a"{{.*}} "-target-feature" "+fprcvt"{{.*}} "-target-feature" "+sve2p3"{{.*}}
 
 // ===== Features supported on aarch64 =====
+//
+// RUN: %clang -target aarch64 -march=armv9.8a+cflt -### -c %s 2>&1 | FileCheck -check-prefix=V98A-CFLT %s
+// RUN: %clang -target aarch64 -march=armv9.8-a+cflt -### -c %s 2>&1 | FileCheck -check-prefix=V98A-CFLT %s
+// V98A-CFLT: "-cc1"{{.*}} "-triple" "aarch64{{.*}}" "-target-cpu" "generic" "-target-feature" "+v9.8a"{{.*}} "-target-feature" "+cflt"
diff --git a/clang/test/Driver/print-supported-extensions-aarch64.c b/clang/test/Driver/print-supported-extensions-aarch64.c
index 1e2882550c81fa..a57fff693eec45 100644
--- a/clang/test/Driver/print-supported-extensions-aarch64.c
+++ b/clang/test/Driver/print-supported-extensions-aarch64.c
@@ -9,6 +9,7 @@
 // CHECK-NEXT:     brbe                FEAT_BRBE                                              Enable Branch Record Buffer Extension
 // CHECK-NEXT:     bti                 FEAT_BTI                                               Enable Branch Target Identification
 // CHECK-NEXT:     btie                FEAT_BTIE                                              Enable Enhanced Branch Target Identification extension
+// CHECK-NEXT:     cflt                FEAT_CFLT                                              Enable Armv9.8-A Conditional Fault instructions
 // CHECK-NEXT:     cmpbr               FEAT_CMPBR                                             Enable Armv9.6-A base compare and branch instructions
 // CHECK-NEXT:     fcma                FEAT_FCMA                                              Enable Armv8.3-A Floating-point complex number support
 // CHECK-NEXT:     cpa                 FEAT_CPA                                               Enable Armv9.5-A Checked Pointer Arithmetic
diff --git a/llvm/lib/Target/AArch64/AArch64Features.td b/llvm/lib/Target/AArch64/AArch64Features.td
index cda947c1bbea0b..fd1db78da1773c 100644
--- a/llvm/lib/Target/AArch64/AArch64Features.td
+++ b/llvm/lib/Target/AArch64/AArch64Features.td
@@ -621,6 +621,9 @@ def FeatureF16F32MM : ExtensionWithMArch<"f16f32mm", "F16F32MM", "FEAT_F16F32MM"
 //  Armv9.8 Architecture Extensions
 //===----------------------------------------------------------------------===//
 
+def FeatureCFLT : ExtensionWithMArch<"cflt", "CFLT", "FEAT_CFLT",
+  "Enable Armv9.8-A Conditional Fault instructions">;
+
 //===----------------------------------------------------------------------===//
 //  Future Architecture Technologies
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/AArch64/AArch64InstrFormats.td b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
index fc603c2d59240f..7bdfd59f328347 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrFormats.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
@@ -522,6 +522,44 @@ def uimm6m1_64b : Operand<i64> {
   let OperandType = "OPERAND_IMMEDIATE";
 }
 
+def uimm9 : Operand<i64> {
+  let ParserMatchClass = AsmImmRange<0, 511>;
+  let OperandType = "OPERAND_IMMEDIATE";
+}
+
+class AdjImmAsmOperand<string name, string diagnostic, int adjustment,
+                       int low, int high> : AsmOperandClass {
+  let Name = name;
+  let DiagnosticType = diagnostic;
+  let RenderMethod = "addAdjImmOperands<" # adjustment # ">";
+  let PredicateMethod = "isImmInRange<" # !sub(low, adjustment) # "," #
+                        !sub(high, adjustment) # ">";
+}
+
+def uimm9p1 : Operand<i64> {
+  let ParserMatchClass =
+      AdjImmAsmOperand<"UImm9P1", "InvalidImm1_512", -1, 0, 511>;
+  let OperandType = "OPERAND_IMMEDIATE";
+}
+
+def uimm9m1 : Operand<i64> {
+  let ParserMatchClass =
+      AdjImmAsmOperand<"UImm9M1", "InvalidImmM1_510", 1, 0, 511>;
+  let OperandType = "OPERAND_IMMEDIATE";
+}
+
+def simm9p1 : Operand<i64> {
+  let ParserMatchClass =
+      AdjImmAsmOperand<"SImm9P1", "InvalidImmM255_256", -1, -256, 255>;
+  let OperandType = "OPERAND_IMMEDIATE";
+}
+
+def simm9m1 : Operand<i64> {
+  let ParserMatchClass =
+      AdjImmAsmOperand<"SImm9M1", "InvalidImmM257_254", 1, -256, 255>;
+  let OperandType = "OPERAND_IMMEDIATE";
+}
+
 def SImm9Operand : SImmOperand<9>;
 def simm9 : Operand<i64>, ImmLeaf<i64, [{ return Imm >= -256 && Imm < 256; }]> {
   let ParserMatchClass = SImm9Operand;
@@ -13658,3 +13696,105 @@ multiclass TEXIT<string asm> {
   def NAME : TEXITInst<asm>;
   def      : InstAlias<asm, (!cast<Instruction>(NAME) 0), 1>;
 }
+
+//----------------------------------------------------------------------------
+// Conditional Fault instructions (FEAT_CFLT)
+//----------------------------------------------------------------------------
+
+class BaseCondFLT
+    : I<(outs), (ins ccode:$cond, uimm16:$imm),
+        "flt", ".$cond\t$imm", "", []>, Sched<[]> {
+  bits<4> cond;
+  bits<16> imm;
+  let Inst{31-21} = 0b11010100001;
+  let Inst{20-5}  = imm;
+  let Inst{4}     = 1;
+  let Inst{3-0}   = cond;
+
+  let Uses = [NZCV];
+}
+
+class BaseFLT<bit sf, dag iops, string asm, string operands>
+    : I<(outs), iops, asm, operands, "", []>, Sched<[]> {
+  bits<2> reason;
+  bits<5> Rt;
+  let Inst{31}    = sf;
+  let Inst{30-24} = 0b1110110;
+  let Inst{15-12} = 0b0000;
+  let Inst{11-10} = reason;
+  let Inst{4-0}   = Rt;
+}
+
+class BaseCFLTImm<RegisterClass regtype, bit sf, Operand immtype,
+                  bits<3> cc, string asm>
+    : BaseFLT<sf, (ins imm0_3:$reason, regtype:$Rt, immtype:$imm),
+              asm, "\t$reason, $Rt, $imm"> {
+  bits<9> imm;
+  let Inst{23-21} = cc;
+  let Inst{20-16} = imm{8-4};
+  let Inst{9}     = 0;
+  let Inst{8-5}   = imm{3-0};
+}
+
+class BaseCFLTReg<RegisterClass regtype, bit sf, bits<3> cc, string asm>
+    : BaseFLT<sf, (ins imm0_3:$reason, regtype:$Rt, regtype:$Rm),
+              asm, "\t$reason, $Rt, $Rm"> {
+  bits<5> Rm;
+  let Inst{23-21} = cc;
+  let Inst{20-16} = Rm;
+  let Inst{9-5}   = 0b10000;
+}
+
+multiclass CFLTImm<bits<3> cc, string asm, Operand immtype> {
+  def Wi : BaseCFLTImm<GPR32, 0, immtype, cc, asm>;
+  def Xi : BaseCFLTImm<GPR64, 1, immtype, cc, asm>;
+}
+
+multiclass CFLTReg<bits<3> cc, string asm> {
+  def Wr : BaseCFLTReg<GPR32sp, 0, cc, asm>;
+  def Xr : BaseCFLTReg<GPR64sp, 1, cc, asm>;
+}
+
+multiclass CFLTRegAlias<string mnemonic, string inst> {
+  def : InstAlias<mnemonic # "\t$reason, $Rm, $Rt",
+                  (!cast<Instruction>(inst # "Wr") imm0_3:$reason,
+                   GPR32sp:$Rt, GPR32sp:$Rm), 0>;
+  def : InstAlias<mnemonic # "\t$reason, $Rm, $Rt",
+                  (!cast<Instruction>(inst # "Xr") imm0_3:$reason,
+                   GPR64sp:$Rt, GPR64sp:$Rm), 0>;
+}
+
+multiclass CFLTImmAlias<string mnemonic, string inst, Operand immtype> {
+  def : InstAlias<mnemonic # "\t$reason, $Rt, $imm",
+                  (!cast<Instruction>(inst # "Wi") imm0_3:$reason,
+                   GPR32:$Rt, immtype:$imm), 0>;
+  def : InstAlias<mnemonic # "\t$reason, $Rt, $imm",
+                  (!cast<Instruction>(inst # "Xi") imm0_3:$reason,
+                   GPR64:$Rt, immtype:$imm), 0>;
+}
+
+def tflt_imm32_63 : Operand<i64> {
+  let ParserMatchClass = TBZImm32_63Operand;
+  let OperandType = "OPERAND_IMMEDIATE";
+  let DecoderMethod = "DecodeTFLTImm32_63";
+}
+
+class BaseTFLT<RegisterClass regtype, Operand immtype, bit sf, bit op,
+               string asm>
+    : BaseFLT<sf, (ins imm0_3:$reason, regtype:$Rt, immtype:$bit_off),
+              asm, "\t$reason, $Rt, $bit_off"> {
+  bits<6> bit_off;
+  let Inst{23-19} = bit_off{4-0};
+  let Inst{18-16} = 0b000;
+  let Inst{9-6}   = 0b1001;
+  let Inst{5}     = op;
+}
+
+multiclass TFLT<bit op, string asm> {
+  def W : BaseTFLT<GPR32, tbz_imm0_31_diag, 0, op, asm>;
+  def X : BaseTFLT<GPR64, tflt_imm32_63, 1, op, asm>;
+
+  def : InstAlias<asm # "\t$reason, $Rt, $imm",
+                  (!cast<Instruction>(NAME # "W") imm0_3:$reason,
+                   GPR32as64:$Rt, tbz_imm0_31_nodiag:$imm), 0>;
+}
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index a23250d4e1d4e6..16131190410e86 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -237,6 +237,8 @@ def HasF16F32DOT     : Predicate<"Subtarget->hasF16F32DOT()">,
                                  AssemblerPredicateWithAll<(all_of FeatureF16F32DOT), "f16f32dot">;
 def HasF16F32MM      : Predicate<"Subtarget->hasF16F32MM()">,
                                  AssemblerPredicateWithAll<(all_of FeatureF16F32MM), "f16f32mm">;
+def HasCFLT          : Predicate<"Subtarget->hasCFLT()">,
+                                 AssemblerPredicateWithAll<(all_of FeatureCFLT), "cflt">;
 
 // A subset of SVE(2) instructions are legal in Streaming SVE execution mode,
 // they should be enabled if either has been specified.
@@ -12756,6 +12758,53 @@ let Predicates = [HasTEV] in {
   defm TEXIT : TEXIT<"texit">;
 }
 
+//===-----------------------------------------------------===//
+// Conditional Fault instructions (FEAT_CFLT)
+//===-----------------------------------------------------===//
+let Predicates = [HasCFLT] in {
+  def FLTcc : BaseCondFLT;
+
+  defm CFLTEQ : CFLTReg<0b110, "cflteq">;
+  defm CFLTEQ : CFLTImm<0b100, "cflteq", simm9>;
+
+  defm CFLTNE : CFLTReg<0b111, "cfltne">;
+  defm CFLTNE : CFLTImm<0b101, "cfltne", simm9>;
+
+  defm CFLTGT : CFLTReg<0b000, "cfltgt">;
+  defm CFLTGT : CFLTImm<0b000, "cfltgt", simm9>;
+
+  defm CFLTGE : CFLTReg<0b001, "cfltge">;
+  defm CFLTLT : CFLTImm<0b001, "cfltlt", simm9>;
+
+  defm CFLTHI : CFLTReg<0b010, "cflthi">;
+  defm CFLTHI : CFLTImm<0b010, "cflthi", uimm9>;
+
+  defm CFLTHS : CFLTReg<0b011, "cflths">;
+  defm CFLTLO : CFLTImm<0b011, "cfltlo", uimm9>;
+
+  defm : CFLTImmAlias<"cfltge", "CFLTGT", simm9p1>;
+  defm : CFLTImmAlias<"cflths", "CFLTHI", uimm9p1>;
+  defm : CFLTImmAlias<"cfltle", "CFLTLT", simm9m1>;
+  defm : CFLTImmAlias<"cfltls", "CFLTLO", uimm9m1>;
+
+  defm : CFLTRegAlias<"cfltle", "CFLTGE">;
+  defm : CFLTRegAlias<"cfltlo", "CFLTHI">;
+  defm : CFLTRegAlias<"cfltls", "CFLTHS">;
+  defm : CFLTRegAlias<"cfltlt", "CFLTGT">;
+
+  def : InstAlias<"cfltnz\t$reason, $Rt",
+                  (CFLTNEWi imm0_3:$reason, GPR32:$Rt, 0), 0>;
+  def : InstAlias<"cfltnz\t$reason, $Rt",
+                  (CFLTNEXi imm0_3:$reason, GPR64:$Rt, 0), 0>;
+  def : InstAlias<"cfltz\t$reason, $Rt",
+                  (CFLTEQWi imm0_3:$reason, GPR32:$Rt, 0), 0>;
+  def : InstAlias<"cfltz\t$reason, $Rt",
+                  (CFLTEQXi imm0_3:$reason, GPR64:$Rt, 0), 0>;
+
+  defm TFLTZ  : TFLT<0, "tfltz">;
+  defm TFLTNZ : TFLT<1, "tfltnz">;
+}
+
 include "AArch64InstrAtomics.td"
 include "AArch64SVEInstrInfo.td"
 include "AArch64SMEInstrInfo.td"
diff --git a/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp b/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
index b2928485d46add..8e9e9c33882a4b 100644
--- a/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
+++ b/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
@@ -1932,6 +1932,12 @@ class AArch64Operand : public MCParsedAsmOperand {
     addExpr(Inst, getImm());
   }
 
+  template <int Adj> void addAdjImmOperands(MCInst &Inst, unsigned N) const {
+    assert(N == 1 && "Invalid number of operands!");
+    int64_t Imm = cast<MCConstantExpr>(getImm())->getValue();
+    Inst.addOperand(MCOperand::createImm(Imm + Adj));
+  }
+
   template <int Shift>
   void addImmWithOptionalShiftOperands(MCInst &Inst, unsigned N) const {
     assert(N == 2 && "Invalid number of operands!");
@@ -3757,6 +3763,7 @@ constexpr EnumStringDef<FeatureBitset> ExtensionDefs[] = {
     {{"pauth-lr"}, {AArch64::FeaturePAuthLR}},
     {{"ssve-fexpa"}, {AArch64::FeatureSSVE_FEXPA}},
     {{"wfxt"}, {AArch64::FeatureWFxT}},
+    {{"cflt"}, {AArch64::FeatureCFLT}},
 };
 constexpr auto ExtensionMap = BUILD_ENUM_STRINGS(ExtensionDefs);
 
@@ -5309,8 +5316,9 @@ bool AArch64AsmParser::parseInstruction(ParseInstructionInfo &Info,
   Operands.push_back(AArch64Operand::CreateToken(Head, NameLoc, getContext()));
   Mnemonic = Head;
 
-  // Handle condition codes for a branch mnemonic
-  if ((Head == "b" || Head == "bc") && Next != StringRef::npos) {
+  // Handle condition codes for a branch or fault mnemonic.
+  if ((Head == "b" || Head == "bc" || Head == "flt") &&
+      Next != StringRef::npos) {
     Start = Next;
     Next = Name.find('.', Start + 1);
     Head = Name.slice(Start + 1, Next);
@@ -6091,6 +6099,8 @@ bool AArch64AsmParser::showMatchError(SMLoc Loc, unsigned ErrCode,
     return Error(Loc, "immediate must be an integer in range [0, 127].");
   case Match_InvalidImm0_255:
     return Error(Loc, "immediate must be an integer in range [0, 255].");
+  case Match_InvalidImm0_511:
+    return Error(Loc, "immediate must be an integer in range [0, 511].");
   case Match_InvalidImm0_65535:
     return Error(Loc, "immediate must be an integer in range [0, 65535].");
   case Match_InvalidHinteUImm16:
@@ -6106,8 +6116,16 @@ bool AArch64AsmParser::showMatchError(SMLoc Loc, unsigned ErrCode,
     return Error(Loc, "immediate must be an integer in range [1, 32].");
   case Match_InvalidImm1_64:
     return Error(Loc, "immediate must be an integer in range [1, 64].");
+  case Match_InvalidImm1_512:
+    return Error(Loc, "immediate must be an integer in range [1, 512].");
   case Match_InvalidImmM1_62:
     return Error(Loc, "immediate must be an integer in range [-1, 62].");
+  case Match_InvalidImmM1_510:
+    return Error(Loc, "immediate must be an integer in range [-1, 510].");
+  case Match_InvalidImmM255_256:
+    return Error(Loc, "immediate must be an integer in range [-255, 256].");
+  case Match_InvalidImmM257_254:
+    return Error(Loc, "immediate must be an integer in range [-257, 254].");
   case Match_InvalidMemoryIndexedRange2UImm0:
     return Error(Loc, "vector select offset must be the immediate range 0:1.");
   case Match_InvalidMemoryIndexedRange2UImm1:
@@ -6879,13 +6897,18 @@ bool AArch64AsmParser::matchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
   case Match_InvalidImm0_63:
   case Match_InvalidImm0_127:
   case Match_InvalidImm0_255:
+  case Match_InvalidImm0_511:
   case Match_InvalidImm0_65535:
   case Match_InvalidHinteUImm16:
   case Match_InvalidImm1_8:
   case Match_InvalidImm1_16:
   case Match_InvalidImm1_32:
   case Match_InvalidImm1_64:
+  case Match_InvalidImm1_512:
   case Match_InvalidImmM1_62:
+  case Match_InvalidImmM1_510:
+  case Match_InvalidImmM255_256:
+  case Match_InvalidImmM257_254:
   case Match_InvalidMemoryIndexedRange2UImm0:
   case Match_InvalidMemoryIndexedRange2UImm1:
   case Match_InvalidMemoryIndexedRange2UImm2:
@@ -7050,6 +7073,11 @@ bool AArch64AsmParser::matchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
   case Match_MRS: {
     if (ErrorInfo >= Operands.size())
       return Error(IDLoc, "too few operands for instruction", SMRange(IDLoc, (*Operands.back()).getEndLoc()));
+    // CFLT has both register and immediate forms. The matcher may select an
+    // immediate-form failure for an invalid register operand.
+    if (Tok.starts_with("cflt") &&
+        static_cast<AArch64Operand &>(*Operands[ErrorInfo]).isScalarReg())
+      MatchResult = Match_InvalidOperand;
     // Any time we get here, there's nothing fancy to do. Just get the
     // operand SMLoc and display the diagnostic.
     SMLoc ErrorLoc = ((AArch64Operand &)*Operands[ErrorInfo]).getStartLoc();
@@ -8772,18 +8800,13 @@ ParseStatus AArch64AsmParser::tryParseAdjImm0_63(OperandVector &Operands) {
   SMLoc S = getLoc();
 
   parseOptionalToken(AsmToken::Hash);
-  bool IsNegative = parseOptionalToken(AsmToken::Minus);
 
-  if (getTok().isNot(AsmToken::Integer))
+  if (getTok().isNot(AsmToken::Integer) && getTok().isNot(AsmToken::Minus))
     return ParseStatus::NoMatch;
 
-  const MCExpr *Ex;
-  if (getParser().parseExpression(Ex))
-    return ParseStatus::NoMatch;
-
-  int64_t Imm = dyn_cast<MCConstantExpr>(Ex)->getValue();
-  if (IsNegative)
-    Imm = -Imm;
+  int64_t Imm;
+  if (parseImmExpr(Imm))
+    return ParseStatus::Failure;
 
   // We want an adjusted immediate in the range [0, 63]. If we don't have one,
   // return a value, which is certain to trigger a error message about invalid
diff --git a/llvm/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp b/llvm/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp
index e7820f7d6c5b13..0dbfb5e50013e9 100644
--- a/llvm/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp
+++ b/llvm/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp
@@ -1356,6 +1356,13 @@ static DecodeStatus DecodeTestAndBranch(MCInst &Inst, uint32_t insn,
   return Success;
 }
 
+static DecodeStatus DecodeTFLTImm32_63(MCInst &Inst, unsigned Imm,
+                                       uint64_t Addr,
+                                       const MCDisassembler *Decoder) {
+  Inst.addOperand(MCOperand::createImm(Imm | 0x20));
+  return Success;
+}
+
 static DecodeStatus
 DecodeGPRSeqPairsClassRegisterClass(MCInst &Inst, unsigned RegClassID,
                                     unsigned RegNo, uint64_t Addr,
diff --git a/llvm/test/MC/AArch64/armv9.8a-cflt-diagnostics.s b/llvm/test/MC/AArch64/armv9.8a-cflt-diagnostics.s
new file mode 100644
index 00000000000000..d4ab13432d7f15
--- /dev/null
+++ b/llvm/test/MC/AArch64/armv9.8a-cflt-diagnostics.s
@@ -0,0 +1,89 @@
+// RUN: not llvm-mc -triple=aarch64 -mattr=+cflt -show-encoding < %s 2>&1 \
+// RUN:        | FileCheck %s
+
+flt.me #0
+// CHECK: [[@LINE-1]]:5: error: invalid condition code
+
+flt.eq #65536
+// CHECK: [[@LINE-1]]:8: error: immediate must be an integer in range [0, 65535].
+
+cflteq #0, wsp, #0
+// CHECK: [[@LINE-1]]:17: error: invalid operand for instruction
+
+cflteq #0, sp, #0
+// CHECK: [[@LINE-1]]:16: error: invalid operand for instruction
+
+cflteq #4, w0, #1
+// CHECK: [[@LINE-1]]:8: error: immediate must be an integer in range [0, 3].
+
+cfltgt #0, w0, #-257
+// CHECK: [[@LINE-1]]:16: error: index must be an integer in range [-256, 255].
+
+cfltgt #0, w0, #256
+// CHECK: [[@LINE-1]]:16: error: index must be an integer in range [-256, 255].
+
+cflthi #0, w0, #-1
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [0, 511].
+
+cflthi #0, w0, #512
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [0, 511].
+
+cfltge #0, w0, #-256
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [-255, 256].
+
+cfltge #0, w0, #257
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [-255, 256].
+
+cflths #0, w0, #0
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [1, 512].
+
+cflths #0, w0, #513
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [1, 512].
+
+cfltle #0, w0, #-258
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [-257, 254].
+
+cfltle #0, w0, #255
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [-257, 254].
+
+cfltls #0, w0, #-2
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [-1, 510].
+
+cfltls #0, w0, #511
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [-1, 510].
+
+cfltlo #0, w0, #-1
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [0, 511].
+
+cfltlo #0, w0, #512
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [0, 511].
+
+cflteq #0, wzr, w0
+// CHECK: [[@LINE-1]]:17: error: invalid operand for instruction
+
+cflteq #0, xzr, x0
+// CHECK: [[@LINE-1]]:17: error: invalid operand for instruction
+
+cflteq #0, w0, wzr
+// CHECK: [[@LINE-1]]:16: error: invalid operand for instruction
+
+cflteq #0, x0, xzr
+// CHECK: [[@LINE-1]]:16: error: invalid operand for instruction
+
+cfltz #0, wsp
+// CHECK: [[@LINE-1]]:11: error: invalid operand for instruction
+
+cfltnz #0, sp
+// CHECK: [[@LINE-1]]:12: error: invalid operand for instruction
+
+tfltz #4, w0, #0
+// CHECK: [[@LINE-1]]:7: error: immediate must be an integer in range [0, 3].
+
+tfltz #0, w0, #32
+// CHECK: [[@LINE-1]]:15: error: immediate must be an integer in range [0, 31].
+
+tfltnz #4, x0, #32
+// CHECK: [[@LINE-1]]:8: error: immediate must be an integer in range [0, 3].
+
+tfltnz #0, x0, #64
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [0, 63].
diff --git a/llvm/test/MC/AArch64/armv9.8a-cflt.s b/llvm/test/MC/AArch64/armv9.8a-cflt.s
new file mode 100644
index 00000000000000..8a648037542450
--- /dev/null
+++ b/llvm/test/MC/AArch64/armv9.8a-cflt.s
@@ -0,0 +1,329 @@
+// RUN: llvm-mc -triple=aarch64 -show-encoding -mattr=+cflt < %s \
+// RUN:        | FileCheck %s --check-prefixes=CHECK-ENCODING,CHECK-INST
+// RUN: not llvm-mc -triple=aarch64 -show-encoding < %s 2>&1 \
+// RUN:        | FileCheck %s --check-prefix=CHECK-ERROR
+// RUN: llvm-mc -triple=aarch64 -filetype=obj -mattr=+cflt < %s \
+// RUN:        | llvm-objdump -d --mattr=+cflt --no-print-imm-hex - | FileCheck %s --check-prefix=CHECK-INST
+// RUN: llvm-mc -triple=aarch64 -filetype=obj -mattr=+cflt < %s \
+// RUN:        | llvm-objdump -d --mattr=-cflt --no-print-imm-hex - | FileCheck %s --check-prefix=CHECK-UNKNOWN
+// Disassemble encoding and check the re-encoding (-show-encoding) matches.
+// RUN: llvm-mc -triple=aarch64 -show-encoding -mattr=+cflt < %s \
+// RUN:        | sed '/.text/d' | sed 's/.*encoding: //g' \
+// RUN:        | llvm-mc -triple=aarch64 -mattr=+cflt -disassemble -show-encoding \
+// RUN:        | FileCheck %s --check-prefixes=CHECK-ENCODING,CHECK-INST
+
+//------------------------------------------------------------------------------
+// Conditional Fault instructions (FEAT_CFLT)
+//------------------------------------------------------------------------------
+
+flt.eq #0
+// CHECK-INST: flt.eq #0
+// CHECK-ENCODING: [0x10,0x00,0x20,0xd4]
+// CHECK-UNKNOWN: d4200010
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.ne #1
+// CHECK-INST: flt.ne #1
+// CHECK-ENCODING: [0x31,0x00,0x20,0xd4]
+// CHECK-UNKNOWN: d4200031
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.cs #2
+// CHECK-INST: flt.hs #2
+// CHECK-ENCODING: [0x52,0x00,0x20,0xd4]
+// CHECK-UNKNOWN: d4200052
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.hs #2
+// CHECK-INST: flt.hs #2
+// CHECK-ENCODING: [0x52,0x00,0x20,0xd4]
+// CHECK-UNKNOWN: d4200052
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.cc #3
+// CHECK-INST: flt.lo #3
+// CHECK-ENCODING: [0x73,0x00,0x20,0xd4]
+// CHECK-UNKNOWN: d4200073
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.lo #3
+// CHECK-INST: flt.lo #3
+// CHECK-ENCODING: [0x73,0x00,0x20,0xd4]
+// CHECK-UNKNOWN: d4200073
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.mi #4
+// CHECK-INST: flt.mi #4
+// CHECK-ENCODING: [0x94,0x00,0x20,0xd4]
+// CHECK-UNKNOWN: d4200094
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.pl #5
+// CHECK-INST: flt.pl #5
+// CHECK-ENCODING: [0xb5,0x00,0x20,0xd4]
+// CHECK-UNKNOWN: d42000b5
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.vs #6
+// CHECK-INST: flt.vs #6
+// CHECK-ENCODING: [0xd6,0x00,0x20,0xd4]
+// CHECK-UNKNOWN: d42000d6
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.vc #7
+// CHECK-INST: flt.vc #7
+// CHECK-ENCODING: [0xf7,0x00,0x20,0xd4]
+// CHECK-UNKNOWN: d42000f7
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.hi #8
+// CHECK-INST: flt.hi #8
+// CHECK-ENCODING: [0x18,0x01,0x20,0xd4]
+// CHECK-UNKNOWN: d4200118
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.ls #9
+// CHECK-INST: flt.ls #9
+// CHECK-ENCODING: [0x39,0x01,0x20,0xd4]
+// CHECK-UNKNOWN: d4200139
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.ge #10
+// CHECK-INST: flt.ge #10
+// CHECK-ENCODING: [0x5a,0x01,0x20,0xd4]
+// CHECK-UNKNOWN: d420015a
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.lt #11
+// CHECK-INST: flt.lt #11
+// CHECK-ENCODING: [0x7b,0x01,0x20,0xd4]
+// CHECK-UNKNOWN: d420017b
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.gt #12
+// CHECK-INST: flt.gt #12
+// CHECK-ENCODING: [0x9c,0x01,0x20,0xd4]
+// CHECK-UNKNOWN: d420019c
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.le #13
+// CHECK-INST: flt.le #13
+// CHECK-ENCODING: [0xbd,0x01,0x20,0xd4]
+// CHECK-UNKNOWN: d42001bd
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.al #65535
+// CHECK-INST: flt.al #65535
+// CHECK-ENCODING: [0xfe,0xff,0x3f,0xd4]
+// CHECK-UNKNOWN: d43ffffe
+// CHECK-ERROR: error: instruction requires: cflt
+
+flt.nv #15
+// CHECK-INST: flt.nv #15
+// CHECK-ENCODING: [0xff,0x01,0x20,0xd4]
+// CHECK-UNKNOWN: d42001ff
+// CHECK-ERROR: error: instruction requires: cflt
+
+// CFLT<cc> (immediate).
+
+cflteq #0, w0, #1
+// CHECK-INST: cflteq #0, w0, #1
+// CHECK-ENCODING: [0x20,0x00,0x80,0x76]
+// CHECK-UNKNOWN: 76800020
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltne #3, x3, #-1
+// CHECK-INST: cfltne #3, x3, #-1
+// CHECK-ENCODING: [0xe3,0x0d,0xbf,0xf6]
+// CHECK-UNKNOWN: f6bf0de3
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltgt #0, w4, #-256
+// CHECK-INST: cfltgt #0, w4, #-256
+// CHECK-ENCODING: [0x04,0x00,0x10,0x76]
+// CHECK-UNKNOWN: 76100004
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltlt #3, x7, #0
+// CHECK-INST: cfltlt #3, x7, #0
+// CHECK-ENCODING: [0x07,0x0c,0x20,0xf6]
+// CHECK-UNKNOWN: f6200c07
+// CHECK-ERROR: error: instruction requires: cflt
+
+cflthi #1, x9, #511
+// CHECK-INST: cflthi #1, x9, #511
+// CHECK-ENCODING: [0xe9,0x05,0x5f,0xf6]
+// CHECK-UNKNOWN: f65f05e9
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltlo #2, w10, #1
+// CHECK-INST: cfltlo #2, w10, #1
+// CHECK-ENCODING: [0x2a,0x08,0x60,0x76]
+// CHECK-UNKNOWN: 7660082a
+// CHECK-ERROR: error: instruction requires: cflt
+
+// CFLT<cc> (immediate) aliases.
+
+cfltge #0, x0, #(2 - 1)
+// CHECK-INST: cfltgt #0, x0, #0
+// CHECK-ENCODING: [0x00,0x00,0x00,0xf6]
+// CHECK-UNKNOWN: f6000000
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltge #1, x13, #256
+// CHECK-INST: cfltgt #1, x13, #255
+// CHECK-ENCODING: [0xed,0x05,0x0f,0xf6]
+// CHECK-UNKNOWN: f60f05ed
+// CHECK-ERROR: error: instruction requires: cflt
+
+cflths #2, w14, #1
+// CHECK-INST: cflthi #2, w14, #0
+// CHECK-ENCODING: [0x0e,0x08,0x40,0x76]
+// CHECK-UNKNOWN: 7640080e
+// CHECK-ERROR: error: instruction requires: cflt
+
+cflths #2, w14, #+1
+// CHECK-INST: cflthi #2, w14, #0
+// CHECK-ENCODING: [0x0e,0x08,0x40,0x76]
+// CHECK-UNKNOWN: 7640080e
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltle #0, w16, #-257
+// CHECK-INST: cfltlt #0, w16, #-256
+// CHECK-ENCODING: [0x10,0x00,0x30,0x76]
+// CHECK-UNKNOWN: 76300010
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltle #0, w16, #(-257)
+// CHECK-INST: cfltlt #0, w16, #-256
+// CHECK-ENCODING: [0x10,0x00,0x30,0x76]
+// CHECK-UNKNOWN: 76300010
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltls #3, x19, #510
+// CHECK-INST: cfltlo #3, x19, #511
+// CHECK-ENCODING: [0xf3,0x0d,0x7f,0xf6]
+// CHECK-UNKNOWN: f67f0df3
+// CHECK-ERROR: error: instruction requires: cflt
+
+// CFLT<cc> (register).
+
+cflteq #0, w0, wsp
+// CHECK-INST: cflteq #0, w0, wsp
+// CHECK-ENCODING: [0x00,0x02,0xdf,0x76]
+// CHECK-UNKNOWN: 76df0200
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltne #3, x3, x4
+// CHECK-INST: cfltne #3, x3, x4
+// CHECK-ENCODING: [0x03,0x0e,0xe4,0xf6]
+// CHECK-UNKNOWN: f6e40e03
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltgt #0, w4, w5
+// CHECK-INST: cfltgt #0, w4, w5
+// CHECK-ENCODING: [0x04,0x02,0x05,0x76]
+// CHECK-UNKNOWN: 76050204
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltge #3, x7, x8
+// CHECK-INST: cfltge #3, x7, x8
+// CHECK-ENCODING: [0x07,0x0e,0x28,0xf6]
+// CHECK-UNKNOWN: f6280e07
+// CHECK-ERROR: error: instruction requires: cflt
+
+cflthi #0, w8, w9
+// CHECK-INST: cflthi #0, w8, w9
+// CHECK-ENCODING: [0x08,0x02,0x49,0x76]
+// CHECK-UNKNOWN: 76490208
+// CHECK-ERROR: error: instruction requires: cflt
+
+cflths #3, x11, x12
+// CHECK-INST: cflths #3, x11, x12
+// CHECK-ENCODING: [0x0b,0x0e,0x6c,0xf6]
+// CHECK-UNKNOWN: f66c0e0b
+// CHECK-ERROR: error: instruction requires: cflt
+
+// CFLT<cc> (register) aliases.
+
+cfltle #0, w13, w14
+// CHECK-INST: cfltge #0, w14, w13
+// CHECK-ENCODING: [0x0e,0x02,0x2d,0x76]
+// CHECK-UNKNOWN: 762d020e
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltlo #3, x16, x17
+// CHECK-INST: cflthi #3, x17, x16
+// CHECK-ENCODING: [0x11,0x0e,0x50,0xf6]
+// CHECK-UNKNOWN: f6500e11
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltls #0, w17, w18
+// CHECK-INST: cflths #0, w18, w17
+// CHECK-ENCODING: [0x12,0x02,0x71,0x76]
+// CHECK-UNKNOWN: 76710212
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltlt #3, x20, x21
+// CHECK-INST: cfltgt #3, x21, x20
+// CHECK-ENCODING: [0x15,0x0e,0x14,0xf6]
+// CHECK-UNKNOWN: f6140e15
+// CHECK-ERROR: error: instruction requires: cflt
+
+// CFLTZ and CFLTNZ.
+
+cfltz #0, w21
+// CHECK-INST: cflteq #0, w21, #0
+// CHECK-ENCODING: [0x15,0x00,0x80,0x76]
+// CHECK-UNKNOWN: 76800015
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltnz #3, x24
+// CHECK-INST: cfltne #3, x24, #0
+// CHECK-ENCODING: [0x18,0x0c,0xa0,0xf6]
+// CHECK-UNKNOWN: f6a00c18
+// CHECK-ERROR: error: instruction requires: cflt
+
+cfltnz #3, xzr
+// CHECK-INST: cfltne #3, xzr, #0
+// CHECK-ENCODING: [0x1f,0x0c,0xa0,0xf6]
+// CHECK-UNKNOWN: f6a00c1f
+// CHECK-ERROR: error: instruction requires: cflt
+
+// TFLTZ and TFLTNZ.
+
+tfltz #0, w0, #0
+// CHECK-INST: tfltz #0, w0, #0
+// CHECK-ENCODING: [0x40,0x02,0x00,0x76]
+// CHECK-UNKNOWN: 76000240
+// CHECK-ERROR: error: instruction requires: cflt
+
+tfltz #0, x0, #0
+// CHECK-INST: tfltz #0, w0, #0
+// CHECK-ENCODING: [0x40,0x02,0x00,0x76]
+// CHECK-UNKNOWN: 76000240
+// CHECK-ERROR: error: instruction requires: cflt
+
+tfltz #1, x1, #32
+// CHECK-INST: tfltz #1, x1, #32
+// CHECK-ENCODING: [0x41,0x06,0x00,0xf6]
+// CHECK-UNKNOWN: f6000641
+// CHECK-ERROR: error: instruction requires: cflt
+
+tfltnz #2, w3, #31
+// CHECK-INST: tfltnz #2, w3, #31
+// CHECK-ENCODING: [0x63,0x0a,0xf8,0x76]
+// CHECK-UNKNOWN: 76f80a63
+// CHECK-ERROR: error: instruction requires: cflt
+
+tfltnz #3, xzr, #31
+// CHECK-INST: tfltnz #3, wzr, #31
+// CHECK-ENCODING: [0x7f,0x0e,0xf8,0x76]
+// CHECK-UNKNOWN: 76f80e7f
+// CHECK-ERROR: error: instruction requires: cflt
+
+tfltnz #3, x4, #63
+// CHECK-INST: tfltnz #3, x4, #63
+// CHECK-ENCODING: [0x64,0x0e,0xf8,0xf6]
+// CHECK-UNKNOWN: f6f80e64
+// CHECK-ERROR: error: instruction requires: cflt
diff --git a/llvm/test/MC/AArch64/directive-arch-negative.s b/llvm/test/MC/AArch64/directive-arch-negative.s
index 4c17c560971203..2e7bed1ef2692e 100644
--- a/llvm/test/MC/AArch64/directive-arch-negative.s
+++ b/llvm/test/MC/AArch64/directive-arch-negative.s
@@ -79,3 +79,9 @@
 
 # CHECK: error: instruction requires: f8f32mm
 # CHECK-NEXT:   fmmla v0.4s, v1.16b, v2.16b
+
+	.arch armv9-a+cflt+nocflt
+	cfltz #1, w0
+
+# CHECK: error: instruction requires: cflt
+# CHECK-NEXT:   cfltz #1, w0
diff --git a/llvm/test/MC/AArch64/directive-arch.s b/llvm/test/MC/AArch64/directive-arch.s
index ba605cc5d1a698..cd68b6651448f0 100644
--- a/llvm/test/MC/AArch64/directive-arch.s
+++ b/llvm/test/MC/AArch64/directive-arch.s
@@ -38,3 +38,7 @@
 	.arch armv9-a+f8f32mm
 	fmmla v0.4s, v1.16b, v2.16b
 # CHECK:        fmmla v0.4s, v1.16b, v2.16b
+
+	.arch armv9-a+cflt
+	cfltz #1, w0
+# CHECK:        cflteq #1, w0, #0
diff --git a/llvm/test/MC/AArch64/directive-arch_extension-negative.s b/llvm/test/MC/AArch64/directive-arch_extension-negative.s
index 0f01d899151534..7d6f608ea47cda 100644
--- a/llvm/test/MC/AArch64/directive-arch_extension-negative.s
+++ b/llvm/test/MC/AArch64/directive-arch_extension-negative.s
@@ -250,3 +250,9 @@ fmmla v2.8h, v1.16b, v0.16b
 fmmla v2.4s, v1.16b, v0.16b
 // CHECK: [[@LINE-1]]:1: error: instruction requires: f8f32mm
 // CHECK-NEXT: fmmla v2.4s, v1.16b, v0.16b
+
+.arch_extension cflt
+.arch_extension nocflt
+cfltz #1, w0
+// CHECK: [[@LINE-1]]:1: error: instruction requires: cflt
+// CHECK-NEXT: cfltz #1, w0
diff --git a/llvm/test/MC/AArch64/directive-arch_extension.s b/llvm/test/MC/AArch64/directive-arch_extension.s
index f3377fd80c276e..6f4274f0e0edfd 100644
--- a/llvm/test/MC/AArch64/directive-arch_extension.s
+++ b/llvm/test/MC/AArch64/directive-arch_extension.s
@@ -228,3 +228,7 @@ fcmla v0.4s, v1.4s, v2.4s, #0
 .arch_extension bti
 bti c
 // CHECK: bti c
+
+.arch_extension cflt
+cfltz #1, w0
+// CHECK: cflteq #1, w0, #0
diff --git a/llvm/unittests/TargetParser/TargetParserTest.cpp b/llvm/unittests/TargetParser/TargetParserTest.cpp
index 95661bf4a007ea..fa6bf6cb9d0966 100644
--- a/llvm/unittests/TargetParser/TargetParserTest.cpp
+++ b/llvm/unittests/TargetParser/TargetParserTest.cpp
@@ -1508,6 +1508,7 @@ TEST(TargetParserTest, AArch64ExtensionFeatures) {
       AArch64::AEK_BTIE,         AArch64::AEK_F64MM,
       AArch64::AEK_POPS,         AArch64::AEK_SVESM4,
       AArch64::AEK_MTETC,        AArch64::AEK_HINTE,
+      AArch64::AEK_CFLT,
   };
 
   std::vector<StringRef> Features;
@@ -1632,6 +1633,7 @@ TEST(TargetParserTest, AArch64ExtensionFeatures) {
   EXPECT_TRUE(llvm::is_contained(Features, "+tev"));
   EXPECT_TRUE(llvm::is_contained(Features, "+btie"));
   EXPECT_TRUE(llvm::is_contained(Features, "+hinte"));
+  EXPECT_TRUE(llvm::is_contained(Features, "+cflt"));
 
   // Assuming we listed every extension above, this should produce the same
   // result.
@@ -1813,6 +1815,7 @@ TEST(TargetParserTest, AArch64ArchExtFeature) {
       {"tev", "notev", "+tev", "-tev"},
       {"btie", "nobtie", "+btie", "-btie"},
       {"hinte", "nohinte", "+hinte", "-hinte"},
+      {"cflt", "nocflt", "+cflt", "-cflt"},
   };
 
   for (unsigned i = 0; i < std::size(ArchExt); i++) {

>From f07b28484bc15614ebeb5ab5ad11403b11788051 Mon Sep 17 00:00:00 2001
From: Jonathan Thackray <jonathan.thackray at arm.com>
Date: Thu, 8 Oct 2026 16:15:18 +0100
Subject: [PATCH 2/2] fixup! Remove `DecodeTFLTImm32_63` and `tflt_imm32_63`

---
 .../lib/Target/AArch64/AArch64InstrFormats.td | 20 ++++++++-----------
 .../AArch64/AsmParser/AArch64AsmParser.cpp    | 13 ++++++++----
 .../Disassembler/AArch64Disassembler.cpp      |  7 -------
 .../MC/AArch64/armv9.8a-cflt-diagnostics.s    |  6 ++++++
 llvm/test/MC/AArch64/armv9.8a-cflt.s          | 12 +++++++++++
 5 files changed, 35 insertions(+), 23 deletions(-)

diff --git a/llvm/lib/Target/AArch64/AArch64InstrFormats.td b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
index 7bdfd59f328347..ce6c98c29b7424 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrFormats.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrFormats.td
@@ -527,6 +527,7 @@ def uimm9 : Operand<i64> {
   let OperandType = "OPERAND_IMMEDIATE";
 }
 
+// TODO: Use AdjImmAsmOperand for the uimm6m1 and uimm6p1 operands too.
 class AdjImmAsmOperand<string name, string diagnostic, int adjustment,
                        int low, int high> : AsmOperandClass {
   let Name = name;
@@ -1162,6 +1163,7 @@ def imm0_31 : Operand<i64>, ImmLeaf<i64, [{
   return ((uint64_t)Imm) < 32;
 }]> {
   let ParserMatchClass = Imm0_31Operand;
+  let MCOperandPredicate = [{ return MCOp.isImm() && isUInt<5>(MCOp.getImm()); }];
 }
 
 // timm0_31 predicate - same ass imm0_31, but use TargetConstant (TimmLeaf)
@@ -13773,17 +13775,12 @@ multiclass CFLTImmAlias<string mnemonic, string inst, Operand immtype> {
                    GPR64:$Rt, immtype:$imm), 0>;
 }
 
-def tflt_imm32_63 : Operand<i64> {
-  let ParserMatchClass = TBZImm32_63Operand;
-  let OperandType = "OPERAND_IMMEDIATE";
-  let DecoderMethod = "DecodeTFLTImm32_63";
-}
-
-class BaseTFLT<RegisterClass regtype, Operand immtype, bit sf, bit op,
+class BaseTFLT<RegisterClass regtype, Operand immtype, bit op,
                string asm>
-    : BaseFLT<sf, (ins imm0_3:$reason, regtype:$Rt, immtype:$bit_off),
+    : BaseFLT<0, (ins imm0_3:$reason, regtype:$Rt, immtype:$bit_off),
               asm, "\t$reason, $Rt, $bit_off"> {
   bits<6> bit_off;
+  let Inst{31} = bit_off{5};
   let Inst{23-19} = bit_off{4-0};
   let Inst{18-16} = 0b000;
   let Inst{9-6}   = 0b1001;
@@ -13791,10 +13788,9 @@ class BaseTFLT<RegisterClass regtype, Operand immtype, bit sf, bit op,
 }
 
 multiclass TFLT<bit op, string asm> {
-  def W : BaseTFLT<GPR32, tbz_imm0_31_diag, 0, op, asm>;
-  def X : BaseTFLT<GPR64, tflt_imm32_63, 1, op, asm>;
+  def NAME : BaseTFLT<GPR64, imm0_63, op, asm>;
 
   def : InstAlias<asm # "\t$reason, $Rt, $imm",
-                  (!cast<Instruction>(NAME # "W") imm0_3:$reason,
-                   GPR32as64:$Rt, tbz_imm0_31_nodiag:$imm), 0>;
+                  (!cast<Instruction>(NAME) imm0_3:$reason,
+                   GPR64as32:$Rt, imm0_31:$imm), 1>;
 }
diff --git a/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp b/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
index 8e9e9c33882a4b..4497f97e6f63e9 100644
--- a/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
+++ b/llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp
@@ -8800,13 +8800,18 @@ ParseStatus AArch64AsmParser::tryParseAdjImm0_63(OperandVector &Operands) {
   SMLoc S = getLoc();
 
   parseOptionalToken(AsmToken::Hash);
+  bool IsNegative = parseOptionalToken(AsmToken::Minus);
 
-  if (getTok().isNot(AsmToken::Integer) && getTok().isNot(AsmToken::Minus))
+  if (getTok().isNot(AsmToken::Integer))
     return ParseStatus::NoMatch;
 
-  int64_t Imm;
-  if (parseImmExpr(Imm))
-    return ParseStatus::Failure;
+  const MCExpr *Ex;
+  if (getParser().parseExpression(Ex))
+    return ParseStatus::NoMatch;
+
+  int64_t Imm = dyn_cast<MCConstantExpr>(Ex)->getValue();
+  if (IsNegative)
+    Imm = -Imm;
 
   // We want an adjusted immediate in the range [0, 63]. If we don't have one,
   // return a value, which is certain to trigger a error message about invalid
diff --git a/llvm/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp b/llvm/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp
index 0dbfb5e50013e9..e7820f7d6c5b13 100644
--- a/llvm/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp
+++ b/llvm/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp
@@ -1356,13 +1356,6 @@ static DecodeStatus DecodeTestAndBranch(MCInst &Inst, uint32_t insn,
   return Success;
 }
 
-static DecodeStatus DecodeTFLTImm32_63(MCInst &Inst, unsigned Imm,
-                                       uint64_t Addr,
-                                       const MCDisassembler *Decoder) {
-  Inst.addOperand(MCOperand::createImm(Imm | 0x20));
-  return Success;
-}
-
 static DecodeStatus
 DecodeGPRSeqPairsClassRegisterClass(MCInst &Inst, unsigned RegClassID,
                                     unsigned RegNo, uint64_t Addr,
diff --git a/llvm/test/MC/AArch64/armv9.8a-cflt-diagnostics.s b/llvm/test/MC/AArch64/armv9.8a-cflt-diagnostics.s
index d4ab13432d7f15..b9c6683a99d226 100644
--- a/llvm/test/MC/AArch64/armv9.8a-cflt-diagnostics.s
+++ b/llvm/test/MC/AArch64/armv9.8a-cflt-diagnostics.s
@@ -82,8 +82,14 @@ tfltz #4, w0, #0
 tfltz #0, w0, #32
 // CHECK: [[@LINE-1]]:15: error: immediate must be an integer in range [0, 31].
 
+tfltz #0, w0, #-1
+// CHECK: [[@LINE-1]]:15: error: immediate must be an integer in range [0, 31].
+
 tfltnz #4, x0, #32
 // CHECK: [[@LINE-1]]:8: error: immediate must be an integer in range [0, 3].
 
 tfltnz #0, x0, #64
 // CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [0, 63].
+
+tfltnz #0, x0, #-1
+// CHECK: [[@LINE-1]]:16: error: immediate must be an integer in range [0, 63].
diff --git a/llvm/test/MC/AArch64/armv9.8a-cflt.s b/llvm/test/MC/AArch64/armv9.8a-cflt.s
index 8a648037542450..2a7ea280576f7e 100644
--- a/llvm/test/MC/AArch64/armv9.8a-cflt.s
+++ b/llvm/test/MC/AArch64/armv9.8a-cflt.s
@@ -310,6 +310,12 @@ tfltz #1, x1, #32
 // CHECK-UNKNOWN: f6000641
 // CHECK-ERROR: error: instruction requires: cflt
 
+tfltz #3, wzr, #31
+// CHECK-INST: tfltz #3, wzr, #31
+// CHECK-ENCODING: [0x5f,0x0e,0xf8,0x76]
+// CHECK-UNKNOWN: 76f80e5f
+// CHECK-ERROR: error: instruction requires: cflt
+
 tfltnz #2, w3, #31
 // CHECK-INST: tfltnz #2, w3, #31
 // CHECK-ENCODING: [0x63,0x0a,0xf8,0x76]
@@ -322,6 +328,12 @@ tfltnz #3, xzr, #31
 // CHECK-UNKNOWN: 76f80e7f
 // CHECK-ERROR: error: instruction requires: cflt
 
+tfltnz #3, xzr, #32
+// CHECK-INST: tfltnz #3, xzr, #32
+// CHECK-ENCODING: [0x7f,0x0e,0x00,0xf6]
+// CHECK-UNKNOWN: f6000e7f
+// CHECK-ERROR: error: instruction requires: cflt
+
 tfltnz #3, x4, #63
 // CHECK-INST: tfltnz #3, x4, #63
 // CHECK-ENCODING: [0x64,0x0e,0xf8,0xf6]



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