[llvm] Reland "[AArch64][SME] Port all SME routines to RuntimeLibcalls" (PR #153417)

Benjamin Maxwell via llvm-commits llvm-commits at lists.llvm.org
Fri Aug 15 00:57:23 PDT 2025


https://github.com/MacDue updated https://github.com/llvm/llvm-project/pull/153417

>From faa2fe9e11ce5b04ac8711ffe4c381bd66691943 Mon Sep 17 00:00:00 2001
From: Benjamin Maxwell <benjamin.maxwell at arm.com>
Date: Thu, 7 Aug 2025 13:40:49 +0000
Subject: [PATCH 1/8] [AArch64][SME] Port all SME routines to RuntimeLibcalls

This updates everywhere we emit/check an SME routines to use
RuntimeLibcalls to get the function name and calling convention.

Note: RuntimeLibcallEmitter had some issues with emitting non-unique
variable names for sets of libcalls, so tweaked the output to avoid
the need for variables.
---
 llvm/include/llvm/CodeGen/TargetLowering.h    |  6 +++
 llvm/include/llvm/IR/RuntimeLibcalls.td       | 43 ++++++++++++++++++-
 llvm/include/llvm/IR/RuntimeLibcallsImpl.td   |  3 ++
 .../Target/AArch64/AArch64FrameLowering.cpp   | 16 ++++---
 .../Target/AArch64/AArch64ISelLowering.cpp    | 40 ++++++++---------
 .../AArch64/AArch64TargetTransformInfo.cpp    | 18 +++-----
 llvm/lib/Target/AArch64/SMEABIPass.cpp        | 31 +++++++++----
 .../AArch64/Utils/AArch64SMEAttributes.cpp    | 39 ++++++++++++-----
 .../AArch64/Utils/AArch64SMEAttributes.h      | 18 ++++----
 .../Target/AArch64/SMEAttributesTest.cpp      |  2 +-
 10 files changed, 151 insertions(+), 65 deletions(-)

diff --git a/llvm/include/llvm/CodeGen/TargetLowering.h b/llvm/include/llvm/CodeGen/TargetLowering.h
index ed7495694cc70..a7352de2ad673 100644
--- a/llvm/include/llvm/CodeGen/TargetLowering.h
+++ b/llvm/include/llvm/CodeGen/TargetLowering.h
@@ -3566,6 +3566,12 @@ class LLVM_ABI TargetLoweringBase {
     return Libcalls.getMemcpyName().data();
   }
 
+  /// Check if this is valid libcall for the current module, otherwise
+  /// RTLIB::Unsupported.
+  RTLIB::LibcallImpl getSupportedLibcallImpl(StringRef FuncName) const {
+    return Libcalls.getSupportedLibcallImpl(FuncName);
+  }
+
   /// Get the comparison predicate that's to be used to test the result of the
   /// comparison libcall against zero. This should only be used with
   /// floating-point compare libcalls.
diff --git a/llvm/include/llvm/IR/RuntimeLibcalls.td b/llvm/include/llvm/IR/RuntimeLibcalls.td
index 9072a0aa1531f..9626004cbed42 100644
--- a/llvm/include/llvm/IR/RuntimeLibcalls.td
+++ b/llvm/include/llvm/IR/RuntimeLibcalls.td
@@ -406,6 +406,17 @@ multiclass LibmLongDoubleLibCall<string libcall_basename = !toupper(NAME),
 def SC_MEMCPY : RuntimeLibcall;
 def SC_MEMMOVE : RuntimeLibcall;
 def SC_MEMSET : RuntimeLibcall;
+def SC_MEMCHR: RuntimeLibcall;
+
+// AArch64 SME ABI calls
+def SMEABI_SME_STATE : RuntimeLibcall;
+def SMEABI_TPIDR2_SAVE : RuntimeLibcall;
+def SMEABI_ZA_DISABLE : RuntimeLibcall;
+def SMEABI_TPIDR2_RESTORE : RuntimeLibcall;
+def SMEABI_GET_CURRENT_VG : RuntimeLibcall;
+def SMEABI_SME_STATE_SIZE : RuntimeLibcall;
+def SMEABI_SME_SAVE : RuntimeLibcall;
+def SMEABI_SME_RESTORE : RuntimeLibcall;
 
 // ARM EABI calls
 def AEABI_MEMCPY4 : RuntimeLibcall; // Align 4
@@ -1223,8 +1234,35 @@ defset list<RuntimeLibcallImpl> AArch64LibcallImpls = {
   def __arm_sc_memcpy : RuntimeLibcallImpl<SC_MEMCPY>;
   def __arm_sc_memmove : RuntimeLibcallImpl<SC_MEMMOVE>;
   def __arm_sc_memset : RuntimeLibcallImpl<SC_MEMSET>;
+  def __arm_sc_memchr : RuntimeLibcallImpl<SC_MEMCHR>;
 } // End AArch64LibcallImpls
 
+def __arm_sme_state : RuntimeLibcallImpl<SMEABI_SME_STATE>;
+def __arm_tpidr2_save : RuntimeLibcallImpl<SMEABI_TPIDR2_SAVE>;
+def __arm_za_disable : RuntimeLibcallImpl<SMEABI_ZA_DISABLE>;
+def __arm_tpidr2_restore : RuntimeLibcallImpl<SMEABI_TPIDR2_RESTORE>;
+def __arm_get_current_vg : RuntimeLibcallImpl<SMEABI_GET_CURRENT_VG>;
+def __arm_sme_state_size : RuntimeLibcallImpl<SMEABI_SME_STATE_SIZE>;
+def __arm_sme_save : RuntimeLibcallImpl<SMEABI_SME_SAVE>;
+def __arm_sme_restore : RuntimeLibcallImpl<SMEABI_SME_RESTORE>;
+
+def SMEABI_LibCalls_PreserveMost_From_X0 : LibcallsWithCC<(add
+  __arm_tpidr2_save,
+  __arm_za_disable,
+  __arm_tpidr2_restore),
+  SMEABI_PreserveMost_From_X0>;
+
+def SMEABI_LibCalls_PreserveMost_From_X1 : LibcallsWithCC<(add
+  __arm_get_current_vg,
+  __arm_sme_state_size,
+  __arm_sme_save,
+  __arm_sme_restore),
+  SMEABI_PreserveMost_From_X1>;
+
+def SMEABI_LibCalls_PreserveMost_From_X2 : LibcallsWithCC<(add
+  __arm_sme_state),
+  SMEABI_PreserveMost_From_X2>;
+
 def isAArch64_ExceptArm64EC
     : RuntimeLibcallPredicate<"(TT.isAArch64() && !TT.isWindowsArm64EC())">;
 def isWindowsArm64EC : RuntimeLibcallPredicate<"TT.isWindowsArm64EC()">;
@@ -1244,7 +1282,10 @@ def AArch64SystemLibrary : SystemRuntimeLibrary<
        LibmHasSinCosF32, LibmHasSinCosF64, LibmHasSinCosF128,
        DefaultLibmExp10,
        DefaultStackProtector,
-       SecurityCheckCookieIfWinMSVC)
+       SecurityCheckCookieIfWinMSVC,
+       SMEABI_LibCalls_PreserveMost_From_X0,
+       SMEABI_LibCalls_PreserveMost_From_X1,
+       SMEABI_LibCalls_PreserveMost_From_X2)
 >;
 
 // Prepend a # to every name
diff --git a/llvm/include/llvm/IR/RuntimeLibcallsImpl.td b/llvm/include/llvm/IR/RuntimeLibcallsImpl.td
index 601c291daf89d..b5752c1b69ad8 100644
--- a/llvm/include/llvm/IR/RuntimeLibcallsImpl.td
+++ b/llvm/include/llvm/IR/RuntimeLibcallsImpl.td
@@ -36,6 +36,9 @@ def ARM_AAPCS : LibcallCallingConv<[{CallingConv::ARM_AAPCS}]>;
 def ARM_AAPCS_VFP : LibcallCallingConv<[{CallingConv::ARM_AAPCS_VFP}]>;
 def X86_STDCALL : LibcallCallingConv<[{CallingConv::X86_StdCall}]>;
 def AVR_BUILTIN : LibcallCallingConv<[{CallingConv::AVR_BUILTIN}]>;
+def SMEABI_PreserveMost_From_X0 : LibcallCallingConv<[{CallingConv::AArch64_SME_ABI_Support_Routines_PreserveMost_From_X0}]>;
+def SMEABI_PreserveMost_From_X1 : LibcallCallingConv<[{CallingConv::AArch64_SME_ABI_Support_Routines_PreserveMost_From_X1}]>;
+def SMEABI_PreserveMost_From_X2 : LibcallCallingConv<[{CallingConv::AArch64_SME_ABI_Support_Routines_PreserveMost_From_X2}]>;
 
 /// Abstract definition for functionality the compiler may need to
 /// emit a call to. Emits the RTLIB::Libcall enum - This enum defines
diff --git a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
index 885f2a94f85f5..ba02c82b25aaf 100644
--- a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -1487,8 +1487,11 @@ bool isVGInstruction(MachineBasicBlock::iterator MBBI) {
 
     if (Opc == AArch64::BL) {
       auto Op1 = MBBI->getOperand(0);
-      return Op1.isSymbol() &&
-             (StringRef(Op1.getSymbolName()) == "__arm_get_current_vg");
+      auto &TLI =
+          *MBBI->getMF()->getSubtarget<AArch64Subtarget>().getTargetLowering();
+      char const *GetCurrentVG =
+          TLI.getLibcallName(RTLIB::SMEABI_GET_CURRENT_VG);
+      return Op1.isSymbol() && StringRef(Op1.getSymbolName()) == GetCurrentVG;
     }
   }
 
@@ -3468,6 +3471,7 @@ bool AArch64FrameLowering::spillCalleeSavedRegisters(
     MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
     ArrayRef<CalleeSavedInfo> CSI, const TargetRegisterInfo *TRI) const {
   MachineFunction &MF = *MBB.getParent();
+  auto &TLI = *MF.getSubtarget<AArch64Subtarget>().getTargetLowering();
   const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
   AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
   bool NeedsWinCFI = needsWinCFI(MF);
@@ -3581,11 +3585,11 @@ bool AArch64FrameLowering::spillCalleeSavedRegisters(
               .addReg(AArch64::X0, RegState::Implicit)
               .setMIFlag(MachineInstr::FrameSetup);
 
-        const uint32_t *RegMask = TRI->getCallPreservedMask(
-            MF,
-            CallingConv::AArch64_SME_ABI_Support_Routines_PreserveMost_From_X1);
+        RTLIB::Libcall LC = RTLIB::SMEABI_GET_CURRENT_VG;
+        const uint32_t *RegMask =
+            TRI->getCallPreservedMask(MF, TLI.getLibcallCallingConv(LC));
         BuildMI(MBB, MI, DL, TII.get(AArch64::BL))
-            .addExternalSymbol("__arm_get_current_vg")
+            .addExternalSymbol(TLI.getLibcallName(LC))
             .addRegMask(RegMask)
             .addReg(AArch64::X0, RegState::ImplicitDefine)
             .setMIFlag(MachineInstr::FrameSetup);
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 2072e48914ae6..556b04c2be323 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -3083,13 +3083,12 @@ AArch64TargetLowering::EmitGetSMESaveSize(MachineInstr &MI,
   AArch64FunctionInfo *FuncInfo = MF->getInfo<AArch64FunctionInfo>();
   const TargetInstrInfo *TII = Subtarget->getInstrInfo();
   if (FuncInfo->isSMESaveBufferUsed()) {
+    RTLIB::Libcall LC = RTLIB::SMEABI_SME_STATE_SIZE;
     const AArch64RegisterInfo *TRI = Subtarget->getRegisterInfo();
     BuildMI(*BB, MI, MI.getDebugLoc(), TII->get(AArch64::BL))
-        .addExternalSymbol("__arm_sme_state_size")
+        .addExternalSymbol(getLibcallName(LC))
         .addReg(AArch64::X0, RegState::ImplicitDefine)
-        .addRegMask(TRI->getCallPreservedMask(
-            *MF, CallingConv::
-                     AArch64_SME_ABI_Support_Routines_PreserveMost_From_X1));
+        .addRegMask(TRI->getCallPreservedMask(*MF, getLibcallCallingConv(LC)));
     BuildMI(*BB, MI, MI.getDebugLoc(), TII->get(TargetOpcode::COPY),
             MI.getOperand(0).getReg())
         .addReg(AArch64::X0);
@@ -5739,15 +5738,15 @@ static SDValue getSVEPredicateBitCast(EVT VT, SDValue Op, SelectionDAG &DAG) {
 SDValue AArch64TargetLowering::getRuntimePStateSM(SelectionDAG &DAG,
                                                   SDValue Chain, SDLoc DL,
                                                   EVT VT) const {
-  SDValue Callee = DAG.getExternalSymbol("__arm_sme_state",
+  RTLIB::Libcall LC = RTLIB::SMEABI_SME_STATE;
+  SDValue Callee = DAG.getExternalSymbol(getLibcallName(LC),
                                          getPointerTy(DAG.getDataLayout()));
   Type *Int64Ty = Type::getInt64Ty(*DAG.getContext());
   Type *RetTy = StructType::get(Int64Ty, Int64Ty);
   TargetLowering::CallLoweringInfo CLI(DAG);
   ArgListTy Args;
   CLI.setDebugLoc(DL).setChain(Chain).setLibCallee(
-      CallingConv::AArch64_SME_ABI_Support_Routines_PreserveMost_From_X2,
-      RetTy, Callee, std::move(Args));
+      getLibcallCallingConv(LC), RetTy, Callee, std::move(Args));
   std::pair<SDValue, SDValue> CallResult = LowerCallTo(CLI);
   SDValue Mask = DAG.getConstant(/*PSTATE.SM*/ 1, DL, MVT::i64);
   return DAG.getNode(ISD::AND, DL, MVT::i64, CallResult.first.getOperand(0),
@@ -8600,12 +8599,12 @@ static void analyzeCallOperands(const AArch64TargetLowering &TLI,
 }
 
 static SMECallAttrs
-getSMECallAttrs(const Function &Caller,
+getSMECallAttrs(const Function &Caller, const TargetLowering &TLI,
                 const TargetLowering::CallLoweringInfo &CLI) {
   if (CLI.CB)
-    return SMECallAttrs(*CLI.CB);
+    return SMECallAttrs(*CLI.CB, &TLI);
   if (auto *ES = dyn_cast<ExternalSymbolSDNode>(CLI.Callee))
-    return SMECallAttrs(SMEAttrs(Caller), SMEAttrs(ES->getSymbol()));
+    return SMECallAttrs(SMEAttrs(Caller), SMEAttrs(ES->getSymbol(), TLI));
   return SMECallAttrs(SMEAttrs(Caller), SMEAttrs(SMEAttrs::Normal));
 }
 
@@ -8627,7 +8626,7 @@ bool AArch64TargetLowering::isEligibleForTailCallOptimization(
 
   // SME Streaming functions are not eligible for TCO as they may require
   // the streaming mode or ZA to be restored after returning from the call.
-  SMECallAttrs CallAttrs = getSMECallAttrs(CallerF, CLI);
+  SMECallAttrs CallAttrs = getSMECallAttrs(CallerF, *this, CLI);
   if (CallAttrs.requiresSMChange() || CallAttrs.requiresLazySave() ||
       CallAttrs.requiresPreservingAllZAState() ||
       CallAttrs.caller().hasStreamingBody())
@@ -8921,14 +8920,14 @@ static SDValue emitSMEStateSaveRestore(const AArch64TargetLowering &TLI,
       DAG.getCopyFromReg(Chain, DL, Info->getSMESaveBufferAddr(), MVT::i64);
   Args.push_back(Entry);
 
-  SDValue Callee =
-      DAG.getExternalSymbol(IsSave ? "__arm_sme_save" : "__arm_sme_restore",
-                            TLI.getPointerTy(DAG.getDataLayout()));
+  RTLIB::Libcall LC =
+      IsSave ? RTLIB::SMEABI_SME_SAVE : RTLIB::SMEABI_SME_RESTORE;
+  SDValue Callee = DAG.getExternalSymbol(TLI.getLibcallName(LC),
+                                         TLI.getPointerTy(DAG.getDataLayout()));
   auto *RetTy = Type::getVoidTy(*DAG.getContext());
   TargetLowering::CallLoweringInfo CLI(DAG);
   CLI.setDebugLoc(DL).setChain(Chain).setLibCallee(
-      CallingConv::AArch64_SME_ABI_Support_Routines_PreserveMost_From_X1, RetTy,
-      Callee, std::move(Args));
+      TLI.getLibcallCallingConv(LC), RetTy, Callee, std::move(Args));
   return TLI.LowerCallTo(CLI).second;
 }
 
@@ -9116,7 +9115,7 @@ AArch64TargetLowering::LowerCall(CallLoweringInfo &CLI,
   }
 
   // Determine whether we need any streaming mode changes.
-  SMECallAttrs CallAttrs = getSMECallAttrs(MF.getFunction(), CLI);
+  SMECallAttrs CallAttrs = getSMECallAttrs(MF.getFunction(), *this, CLI);
 
   auto DescribeCallsite =
       [&](OptimizationRemarkAnalysis &R) -> OptimizationRemarkAnalysis & {
@@ -9693,11 +9692,12 @@ AArch64TargetLowering::LowerCall(CallLoweringInfo &CLI,
 
   if (RequiresLazySave) {
     // Conditionally restore the lazy save using a pseudo node.
+    RTLIB::Libcall LC = RTLIB::SMEABI_TPIDR2_RESTORE;
     TPIDR2Object &TPIDR2 = FuncInfo->getTPIDR2Obj();
     SDValue RegMask = DAG.getRegisterMask(
-        TRI->SMEABISupportRoutinesCallPreservedMaskFromX0());
+        TRI->getCallPreservedMask(MF, getLibcallCallingConv(LC)));
     SDValue RestoreRoutine = DAG.getTargetExternalSymbol(
-        "__arm_tpidr2_restore", getPointerTy(DAG.getDataLayout()));
+        getLibcallName(LC), getPointerTy(DAG.getDataLayout()));
     SDValue TPIDR2_EL0 = DAG.getNode(
         ISD::INTRINSIC_W_CHAIN, DL, MVT::i64, Result,
         DAG.getConstant(Intrinsic::aarch64_sme_get_tpidr2, DL, MVT::i32));
@@ -29036,7 +29036,7 @@ bool AArch64TargetLowering::fallBackToDAGISel(const Instruction &Inst) const {
 
   // Checks to allow the use of SME instructions
   if (auto *Base = dyn_cast<CallBase>(&Inst)) {
-    auto CallAttrs = SMECallAttrs(*Base);
+    auto CallAttrs = SMECallAttrs(*Base, this);
     if (CallAttrs.requiresSMChange() || CallAttrs.requiresLazySave() ||
         CallAttrs.requiresPreservingZT0() ||
         CallAttrs.requiresPreservingAllZAState())
diff --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
index 3042251cf754d..adf4b33b8021a 100644
--- a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
@@ -220,20 +220,16 @@ static cl::opt<bool> EnableFixedwidthAutovecInStreamingMode(
 static cl::opt<bool> EnableScalableAutovecInStreamingMode(
     "enable-scalable-autovec-in-streaming-mode", cl::init(false), cl::Hidden);
 
-static bool isSMEABIRoutineCall(const CallInst &CI) {
+static bool isSMEABIRoutineCall(const CallInst &CI, const TargetLowering &TLI) {
   const auto *F = CI.getCalledFunction();
-  return F && StringSwitch<bool>(F->getName())
-                  .Case("__arm_sme_state", true)
-                  .Case("__arm_tpidr2_save", true)
-                  .Case("__arm_tpidr2_restore", true)
-                  .Case("__arm_za_disable", true)
-                  .Default(false);
+  return F && SMEAttrs(F->getName(), TLI).isSMEABIRoutine();
 }
 
 /// Returns true if the function has explicit operations that can only be
 /// lowered using incompatible instructions for the selected mode. This also
 /// returns true if the function F may use or modify ZA state.
-static bool hasPossibleIncompatibleOps(const Function *F) {
+static bool hasPossibleIncompatibleOps(const Function *F,
+                                       const TargetLowering &TLI) {
   for (const BasicBlock &BB : *F) {
     for (const Instruction &I : BB) {
       // Be conservative for now and assume that any call to inline asm or to
@@ -242,7 +238,7 @@ static bool hasPossibleIncompatibleOps(const Function *F) {
       // all native LLVM instructions can be lowered to compatible instructions.
       if (isa<CallInst>(I) && !I.isDebugOrPseudoInst() &&
           (cast<CallInst>(I).isInlineAsm() || isa<IntrinsicInst>(I) ||
-           isSMEABIRoutineCall(cast<CallInst>(I))))
+           isSMEABIRoutineCall(cast<CallInst>(I), TLI)))
         return true;
     }
   }
@@ -290,7 +286,7 @@ bool AArch64TTIImpl::areInlineCompatible(const Function *Caller,
   if (CallAttrs.requiresLazySave() || CallAttrs.requiresSMChange() ||
       CallAttrs.requiresPreservingZT0() ||
       CallAttrs.requiresPreservingAllZAState()) {
-    if (hasPossibleIncompatibleOps(Callee))
+    if (hasPossibleIncompatibleOps(Callee, *getTLI()))
       return false;
   }
 
@@ -357,7 +353,7 @@ AArch64TTIImpl::getInlineCallPenalty(const Function *F, const CallBase &Call,
   // change only once and avoid inlining of G into F.
 
   SMEAttrs FAttrs(*F);
-  SMECallAttrs CallAttrs(Call);
+  SMECallAttrs CallAttrs(Call, getTLI());
 
   if (SMECallAttrs(FAttrs, CallAttrs.callee()).requiresSMChange()) {
     if (F == Call.getCaller()) // (1)
diff --git a/llvm/lib/Target/AArch64/SMEABIPass.cpp b/llvm/lib/Target/AArch64/SMEABIPass.cpp
index 4af4d49306625..2008516885c35 100644
--- a/llvm/lib/Target/AArch64/SMEABIPass.cpp
+++ b/llvm/lib/Target/AArch64/SMEABIPass.cpp
@@ -15,11 +15,16 @@
 #include "AArch64.h"
 #include "Utils/AArch64SMEAttributes.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/CodeGen/TargetLowering.h"
+#include "llvm/CodeGen/TargetPassConfig.h"
+#include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicsAArch64.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
+#include "llvm/IR/RuntimeLibcalls.h"
+#include "llvm/Target/TargetMachine.h"
 #include "llvm/Transforms/Utils/Cloning.h"
 
 using namespace llvm;
@@ -33,9 +38,13 @@ struct SMEABI : public FunctionPass {
 
   bool runOnFunction(Function &F) override;
 
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<TargetPassConfig>();
+  }
+
 private:
   bool updateNewStateFunctions(Module *M, Function *F, IRBuilder<> &Builder,
-                               SMEAttrs FnAttrs);
+                               SMEAttrs FnAttrs, const TargetLowering &TLI);
 };
 } // end anonymous namespace
 
@@ -51,14 +60,16 @@ FunctionPass *llvm::createSMEABIPass() { return new SMEABI(); }
 //===----------------------------------------------------------------------===//
 
 // Utility function to emit a call to __arm_tpidr2_save and clear TPIDR2_EL0.
-void emitTPIDR2Save(Module *M, IRBuilder<> &Builder, bool ZT0IsUndef = false) {
+void emitTPIDR2Save(Module *M, IRBuilder<> &Builder, const TargetLowering &TLI,
+                    bool ZT0IsUndef = false) {
   auto &Ctx = M->getContext();
   auto *TPIDR2SaveTy =
       FunctionType::get(Builder.getVoidTy(), {}, /*IsVarArgs=*/false);
   auto Attrs =
       AttributeList().addFnAttribute(Ctx, "aarch64_pstate_sm_compatible");
+  RTLIB::Libcall LC = RTLIB::SMEABI_TPIDR2_SAVE;
   FunctionCallee Callee =
-      M->getOrInsertFunction("__arm_tpidr2_save", TPIDR2SaveTy, Attrs);
+      M->getOrInsertFunction(TLI.getLibcallName(LC), TPIDR2SaveTy, Attrs);
   CallInst *Call = Builder.CreateCall(Callee);
 
   // If ZT0 is undefined (i.e. we're at the entry of a "new_zt0" function), mark
@@ -67,8 +78,7 @@ void emitTPIDR2Save(Module *M, IRBuilder<> &Builder, bool ZT0IsUndef = false) {
   if (ZT0IsUndef)
     Call->addFnAttr(Attribute::get(Ctx, "aarch64_zt0_undef"));
 
-  Call->setCallingConv(
-      CallingConv::AArch64_SME_ABI_Support_Routines_PreserveMost_From_X0);
+  Call->setCallingConv(TLI.getLibcallCallingConv(LC));
 
   // A save to TPIDR2 should be followed by clearing TPIDR2_EL0.
   Function *WriteIntr =
@@ -98,7 +108,8 @@ void emitTPIDR2Save(Module *M, IRBuilder<> &Builder, bool ZT0IsUndef = false) {
 /// interface if it does not share ZA or ZT0.
 ///
 bool SMEABI::updateNewStateFunctions(Module *M, Function *F,
-                                     IRBuilder<> &Builder, SMEAttrs FnAttrs) {
+                                     IRBuilder<> &Builder, SMEAttrs FnAttrs,
+                                     const TargetLowering &TLI) {
   LLVMContext &Context = F->getContext();
   BasicBlock *OrigBB = &F->getEntryBlock();
   Builder.SetInsertPoint(&OrigBB->front());
@@ -124,7 +135,7 @@ bool SMEABI::updateNewStateFunctions(Module *M, Function *F,
 
     // Create a call __arm_tpidr2_save, which commits the lazy save.
     Builder.SetInsertPoint(&SaveBB->back());
-    emitTPIDR2Save(M, Builder, /*ZT0IsUndef=*/FnAttrs.isNewZT0());
+    emitTPIDR2Save(M, Builder, TLI, /*ZT0IsUndef=*/FnAttrs.isNewZT0());
 
     // Enable pstate.za at the start of the function.
     Builder.SetInsertPoint(&OrigBB->front());
@@ -172,10 +183,14 @@ bool SMEABI::runOnFunction(Function &F) {
   if (F.isDeclaration() || F.hasFnAttribute("aarch64_expanded_pstate_za"))
     return false;
 
+  const TargetMachine &TM =
+      getAnalysis<TargetPassConfig>().getTM<TargetMachine>();
+  const TargetLowering &TLI = *TM.getSubtargetImpl(F)->getTargetLowering();
+
   bool Changed = false;
   SMEAttrs FnAttrs(F);
   if (FnAttrs.isNewZA() || FnAttrs.isNewZT0())
-    Changed |= updateNewStateFunctions(M, &F, Builder, FnAttrs);
+    Changed |= updateNewStateFunctions(M, &F, Builder, FnAttrs, TLI);
 
   return Changed;
 }
diff --git a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
index 271094f935e0e..bb788fcebe4ae 100644
--- a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
+++ b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
@@ -7,7 +7,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "AArch64SMEAttributes.h"
+#include "llvm/CodeGen/TargetLowering.h"
 #include "llvm/IR/InstrTypes.h"
+#include "llvm/IR/RuntimeLibcalls.h"
 #include <cassert>
 
 using namespace llvm;
@@ -77,19 +79,36 @@ SMEAttrs::SMEAttrs(const AttributeList &Attrs) {
     Bitmask |= encodeZT0State(StateValue::New);
 }
 
-void SMEAttrs::addKnownFunctionAttrs(StringRef FuncName) {
+void SMEAttrs::addKnownFunctionAttrs(StringRef FuncName,
+                                     const TargetLowering &TLI) {
+  RTLIB::LibcallImpl Impl = TLI.getSupportedLibcallImpl(FuncName);
+  if (Impl == RTLIB::Unsupported)
+    return;
+  RTLIB::Libcall LC = RTLIB::RuntimeLibcallsInfo::getLibcallFromImpl(Impl);
   unsigned KnownAttrs = SMEAttrs::Normal;
-  if (FuncName == "__arm_tpidr2_save" || FuncName == "__arm_sme_state")
+  switch (LC) {
+  case RTLIB::SMEABI_SME_STATE:
+  case RTLIB::SMEABI_TPIDR2_SAVE:
+  case RTLIB::SMEABI_GET_CURRENT_VG:
+  case RTLIB::SMEABI_SME_STATE_SIZE:
+  case RTLIB::SMEABI_SME_SAVE:
+  case RTLIB::SMEABI_SME_RESTORE:
     KnownAttrs |= (SMEAttrs::SM_Compatible | SMEAttrs::SME_ABI_Routine);
-  if (FuncName == "__arm_tpidr2_restore")
+    break;
+  case RTLIB::SMEABI_ZA_DISABLE:
+  case RTLIB::SMEABI_TPIDR2_RESTORE:
     KnownAttrs |= SMEAttrs::SM_Compatible | encodeZAState(StateValue::In) |
                   SMEAttrs::SME_ABI_Routine;
-  if (FuncName == "__arm_sc_memcpy" || FuncName == "__arm_sc_memset" ||
-      FuncName == "__arm_sc_memmove" || FuncName == "__arm_sc_memchr")
+    break;
+  case RTLIB::SC_MEMCPY:
+  case RTLIB::SC_MEMMOVE:
+  case RTLIB::SC_MEMSET:
+  case RTLIB::SC_MEMCHR:
     KnownAttrs |= SMEAttrs::SM_Compatible;
-  if (FuncName == "__arm_sme_save" || FuncName == "__arm_sme_restore" ||
-      FuncName == "__arm_sme_state_size")
-    KnownAttrs |= SMEAttrs::SM_Compatible | SMEAttrs::SME_ABI_Routine;
+    break;
+  default:
+    break;
+  }
   set(KnownAttrs);
 }
 
@@ -110,11 +129,11 @@ bool SMECallAttrs::requiresSMChange() const {
   return true;
 }
 
-SMECallAttrs::SMECallAttrs(const CallBase &CB)
+SMECallAttrs::SMECallAttrs(const CallBase &CB, const TargetLowering *TLI)
     : CallerFn(*CB.getFunction()), CalledFn(SMEAttrs::Normal),
       Callsite(CB.getAttributes()), IsIndirect(CB.isIndirectCall()) {
   if (auto *CalledFunction = CB.getCalledFunction())
-    CalledFn = SMEAttrs(*CalledFunction, SMEAttrs::InferAttrsFromName::Yes);
+    CalledFn = SMEAttrs(*CalledFunction, TLI);
 
   // FIXME: We probably should not allow SME attributes on direct calls but
   // clang duplicates streaming mode attributes at each callsite.
diff --git a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h
index f1be0ecbee7ed..06376c74025f8 100644
--- a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h
+++ b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h
@@ -13,6 +13,8 @@
 
 namespace llvm {
 
+class TargetLowering;
+
 class Function;
 class CallBase;
 class AttributeList;
@@ -48,17 +50,17 @@ class SMEAttrs {
     CallSiteFlags_Mask = ZT0_Undef
   };
 
-  enum class InferAttrsFromName { No, Yes };
-
   SMEAttrs() = default;
   SMEAttrs(unsigned Mask) { set(Mask); }
-  SMEAttrs(const Function &F, InferAttrsFromName Infer = InferAttrsFromName::No)
+  SMEAttrs(const Function &F, const TargetLowering *TLI = nullptr)
       : SMEAttrs(F.getAttributes()) {
-    if (Infer == InferAttrsFromName::Yes)
-      addKnownFunctionAttrs(F.getName());
+    if (TLI)
+      addKnownFunctionAttrs(F.getName(), *TLI);
   }
   SMEAttrs(const AttributeList &L);
-  SMEAttrs(StringRef FuncName) { addKnownFunctionAttrs(FuncName); };
+  SMEAttrs(StringRef FuncName, const TargetLowering &TLI) {
+    addKnownFunctionAttrs(FuncName, TLI);
+  };
 
   void set(unsigned M, bool Enable = true);
 
@@ -146,7 +148,7 @@ class SMEAttrs {
   }
 
 private:
-  void addKnownFunctionAttrs(StringRef FuncName);
+  void addKnownFunctionAttrs(StringRef FuncName, const TargetLowering &TLI);
 };
 
 /// SMECallAttrs is a utility class to hold the SMEAttrs for a callsite. It has
@@ -163,7 +165,7 @@ class SMECallAttrs {
                SMEAttrs Callsite = SMEAttrs::Normal)
       : CallerFn(Caller), CalledFn(Callee), Callsite(Callsite) {}
 
-  SMECallAttrs(const CallBase &CB);
+  SMECallAttrs(const CallBase &CB, const TargetLowering *TLI);
 
   SMEAttrs &caller() { return CallerFn; }
   SMEAttrs &callee() { return IsIndirect ? Callsite : CalledFn; }
diff --git a/llvm/unittests/Target/AArch64/SMEAttributesTest.cpp b/llvm/unittests/Target/AArch64/SMEAttributesTest.cpp
index f13252f3a4c28..e90f733d79fca 100644
--- a/llvm/unittests/Target/AArch64/SMEAttributesTest.cpp
+++ b/llvm/unittests/Target/AArch64/SMEAttributesTest.cpp
@@ -78,7 +78,7 @@ TEST(SMEAttributes, Constructors) {
                             "ret void\n}");
   CallBase &Call =
       cast<CallBase>((CallModule->getFunction("foo")->begin()->front()));
-  ASSERT_TRUE(SMECallAttrs(Call).callsite().hasUndefZT0());
+  ASSERT_TRUE(SMECallAttrs(Call, nullptr).callsite().hasUndefZT0());
 
   // Invalid combinations.
   EXPECT_DEBUG_DEATH(SA(SA::SM_Enabled | SA::SM_Compatible),

>From 97b3cf5d96e028d774637b54e9f8799f02ee66d5 Mon Sep 17 00:00:00 2001
From: Benjamin Maxwell <benjamin.maxwell at arm.com>
Date: Tue, 12 Aug 2025 08:47:01 +0000
Subject: [PATCH 2/8] Rebase: Use RuntimeLibcalls for EmitEntryPStateSM

---
 llvm/lib/Target/AArch64/AArch64ISelLowering.cpp        | 7 +++----
 llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp | 2 +-
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 556b04c2be323..224bbe7e38a19 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -3108,13 +3108,12 @@ AArch64TargetLowering::EmitEntryPStateSM(MachineInstr &MI,
   const TargetInstrInfo *TII = Subtarget->getInstrInfo();
   Register ResultReg = MI.getOperand(0).getReg();
   if (FuncInfo->isPStateSMRegUsed()) {
+    RTLIB::Libcall LC = RTLIB::SMEABI_SME_STATE;
     const AArch64RegisterInfo *TRI = Subtarget->getRegisterInfo();
     BuildMI(*BB, MI, MI.getDebugLoc(), TII->get(AArch64::BL))
-        .addExternalSymbol("__arm_sme_state")
+        .addExternalSymbol(getLibcallName(LC))
         .addReg(AArch64::X0, RegState::ImplicitDefine)
-        .addRegMask(TRI->getCallPreservedMask(
-            *MF, CallingConv::
-                     AArch64_SME_ABI_Support_Routines_PreserveMost_From_X2));
+        .addRegMask(TRI->getCallPreservedMask(*MF, getLibcallCallingConv(LC)));
     BuildMI(*BB, MI, MI.getDebugLoc(), TII->get(TargetOpcode::COPY), ResultReg)
         .addReg(AArch64::X0);
   } else {
diff --git a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
index bb788fcebe4ae..934f68b29922a 100644
--- a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
+++ b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
@@ -93,7 +93,7 @@ void SMEAttrs::addKnownFunctionAttrs(StringRef FuncName,
   case RTLIB::SMEABI_SME_STATE_SIZE:
   case RTLIB::SMEABI_SME_SAVE:
   case RTLIB::SMEABI_SME_RESTORE:
-    KnownAttrs |= (SMEAttrs::SM_Compatible | SMEAttrs::SME_ABI_Routine);
+    KnownAttrs |= SMEAttrs::SM_Compatible | SMEAttrs::SME_ABI_Routine;
     break;
   case RTLIB::SMEABI_ZA_DISABLE:
   case RTLIB::SMEABI_TPIDR2_RESTORE:

>From ddba54e60b7ebf498cbed9e5a9436f6ca6bd46e6 Mon Sep 17 00:00:00 2001
From: Benjamin Maxwell <benjamin.maxwell at arm.com>
Date: Wed, 13 Aug 2025 14:13:49 +0000
Subject: [PATCH 3/8] Avoid TLI.getSupportedLibcallImpl

Rewrite to check a (much smaller) list of libcalls
---
 .../Target/AArch64/AArch64FrameLowering.cpp   | 35 +++++------
 .../AArch64/Utils/AArch64SMEAttributes.cpp    | 58 ++++++++++---------
 .../AArch64/Utils/AArch64SMEAttributes.h      |  2 +-
 3 files changed, 51 insertions(+), 44 deletions(-)

diff --git a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
index ba02c82b25aaf..ae6b486e758c1 100644
--- a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -1475,27 +1475,25 @@ static bool requiresSaveVG(const MachineFunction &MF) {
   return true;
 }
 
-bool isVGInstruction(MachineBasicBlock::iterator MBBI) {
+static bool matchLibcall(const TargetLowering &TLI, const MachineOperand &MO,
+                         RTLIB::Libcall LC) {
+  return MO.isSymbol() && TLI.getLibcallName(LC) == MO.getSymbolName();
+}
+
+bool isVGInstruction(MachineBasicBlock::iterator MBBI,
+                     const TargetLowering &TLI) {
   unsigned Opc = MBBI->getOpcode();
   if (Opc == AArch64::CNTD_XPiI || Opc == AArch64::RDSVLI_XI ||
       Opc == AArch64::UBFMXri)
     return true;
 
-  if (requiresGetVGCall(*MBBI->getMF())) {
-    if (Opc == AArch64::ORRXrr)
-      return true;
+  if (!requiresGetVGCall(*MBBI->getMF()))
+    return false;
 
-    if (Opc == AArch64::BL) {
-      auto Op1 = MBBI->getOperand(0);
-      auto &TLI =
-          *MBBI->getMF()->getSubtarget<AArch64Subtarget>().getTargetLowering();
-      char const *GetCurrentVG =
-          TLI.getLibcallName(RTLIB::SMEABI_GET_CURRENT_VG);
-      return Op1.isSymbol() && StringRef(Op1.getSymbolName()) == GetCurrentVG;
-    }
-  }
+  if (Opc == AArch64::BL)
+    return matchLibcall(TLI, MBBI->getOperand(0), RTLIB::SMEABI_GET_CURRENT_VG);
 
-  return false;
+  return Opc == AArch64::ORRXrr;
 }
 
 // Convert callee-save register save/restore instruction to do stack pointer
@@ -1514,9 +1512,11 @@ static MachineBasicBlock::iterator convertCalleeSaveRestoreToSPPrePostIncDec(
   // functions, we need to do this for both the streaming and non-streaming
   // vector length. Move past these instructions if necessary.
   MachineFunction &MF = *MBB.getParent();
-  if (requiresSaveVG(MF))
-    while (isVGInstruction(MBBI))
+  if (requiresSaveVG(MF)) {
+    auto &TLI = *MF.getSubtarget().getTargetLowering();
+    while (isVGInstruction(MBBI, TLI))
       ++MBBI;
+  }
 
   switch (MBBI->getOpcode()) {
   default:
@@ -2100,11 +2100,12 @@ void AArch64FrameLowering::emitPrologue(MachineFunction &MF,
   // Move past the saves of the callee-saved registers, fixing up the offsets
   // and pre-inc if we decided to combine the callee-save and local stack
   // pointer bump above.
+  auto &TLI = *MF.getSubtarget().getTargetLowering();
   while (MBBI != End && MBBI->getFlag(MachineInstr::FrameSetup) &&
          !IsSVECalleeSave(MBBI)) {
     if (CombineSPBump &&
         // Only fix-up frame-setup load/store instructions.
-        (!requiresSaveVG(MF) || !isVGInstruction(MBBI)))
+        (!requiresSaveVG(MF) || !isVGInstruction(MBBI, TLI)))
       fixupCalleeSaveRestoreStackOffset(*MBBI, AFI->getLocalStackSize(),
                                         NeedsWinCFI, &HasWinCFI);
     ++MBBI;
diff --git a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
index 934f68b29922a..86ef0e0058263 100644
--- a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
+++ b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
@@ -81,34 +81,40 @@ SMEAttrs::SMEAttrs(const AttributeList &Attrs) {
 
 void SMEAttrs::addKnownFunctionAttrs(StringRef FuncName,
                                      const TargetLowering &TLI) {
-  RTLIB::LibcallImpl Impl = TLI.getSupportedLibcallImpl(FuncName);
-  if (Impl == RTLIB::Unsupported)
-    return;
-  RTLIB::Libcall LC = RTLIB::RuntimeLibcallsInfo::getLibcallFromImpl(Impl);
+  struct SMERoutineAttr {
+    RTLIB::Libcall LC{RTLIB::UNKNOWN_LIBCALL};
+    unsigned Attrs{SMEAttrs::Normal};
+  };
+
+  static constexpr unsigned SMCompatiableABIRoutine =
+      SMEAttrs::SM_Compatible | SMEAttrs::SME_ABI_Routine;
+  static constexpr unsigned SMCompatiableABIRoutineInZA =
+      SMCompatiableABIRoutine | encodeZAState(StateValue::In);
+
+  // Table of SME routine -> Known attributes.
+  static constexpr SMERoutineAttr SMERoutineAttrs[]{
+      {RTLIB::SMEABI_SME_STATE, SMCompatiableABIRoutine},
+      {RTLIB::SMEABI_TPIDR2_SAVE, SMCompatiableABIRoutine},
+      {RTLIB::SMEABI_GET_CURRENT_VG, SMCompatiableABIRoutine},
+      {RTLIB::SMEABI_SME_STATE_SIZE, SMCompatiableABIRoutine},
+      {RTLIB::SMEABI_SME_SAVE, SMCompatiableABIRoutine},
+      {RTLIB::SMEABI_SME_RESTORE, SMCompatiableABIRoutine},
+      {RTLIB::SMEABI_ZA_DISABLE, SMCompatiableABIRoutineInZA},
+      {RTLIB::SMEABI_TPIDR2_RESTORE, SMCompatiableABIRoutineInZA},
+      {RTLIB::SC_MEMCPY, SMEAttrs::SM_Compatible},
+      {RTLIB::SC_MEMMOVE, SMEAttrs::SM_Compatible},
+      {RTLIB::SC_MEMSET, SMEAttrs::SM_Compatible},
+      {RTLIB::SC_MEMCHR, SMEAttrs::SM_Compatible},
+  };
+
   unsigned KnownAttrs = SMEAttrs::Normal;
-  switch (LC) {
-  case RTLIB::SMEABI_SME_STATE:
-  case RTLIB::SMEABI_TPIDR2_SAVE:
-  case RTLIB::SMEABI_GET_CURRENT_VG:
-  case RTLIB::SMEABI_SME_STATE_SIZE:
-  case RTLIB::SMEABI_SME_SAVE:
-  case RTLIB::SMEABI_SME_RESTORE:
-    KnownAttrs |= SMEAttrs::SM_Compatible | SMEAttrs::SME_ABI_Routine;
-    break;
-  case RTLIB::SMEABI_ZA_DISABLE:
-  case RTLIB::SMEABI_TPIDR2_RESTORE:
-    KnownAttrs |= SMEAttrs::SM_Compatible | encodeZAState(StateValue::In) |
-                  SMEAttrs::SME_ABI_Routine;
-    break;
-  case RTLIB::SC_MEMCPY:
-  case RTLIB::SC_MEMMOVE:
-  case RTLIB::SC_MEMSET:
-  case RTLIB::SC_MEMCHR:
-    KnownAttrs |= SMEAttrs::SM_Compatible;
-    break;
-  default:
-    break;
+  for (auto [LC, Attrs] : SMERoutineAttrs) {
+    if (TLI.getLibcallName(LC) == FuncName) {
+      KnownAttrs = Attrs;
+      break;
+    }
   }
+
   set(KnownAttrs);
 }
 
diff --git a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h
index 06376c74025f8..bfbb5deec50bd 100644
--- a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h
+++ b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h
@@ -84,7 +84,7 @@ class SMEAttrs {
   static StateValue decodeZAState(unsigned Bitmask) {
     return static_cast<StateValue>((Bitmask & ZA_Mask) >> ZA_Shift);
   }
-  static unsigned encodeZAState(StateValue S) {
+  static constexpr unsigned encodeZAState(StateValue S) {
     return static_cast<unsigned>(S) << ZA_Shift;
   }
 

>From fc90c3dbde66415d6d2047f40ff01989c0bb0911 Mon Sep 17 00:00:00 2001
From: Benjamin Maxwell <benjamin.maxwell at arm.com>
Date: Wed, 13 Aug 2025 14:28:41 +0000
Subject: [PATCH 4/8] Use stringref for check

---
 llvm/lib/Target/AArch64/AArch64FrameLowering.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
index ae6b486e758c1..fddde668b7f1a 100644
--- a/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp
@@ -1477,7 +1477,8 @@ static bool requiresSaveVG(const MachineFunction &MF) {
 
 static bool matchLibcall(const TargetLowering &TLI, const MachineOperand &MO,
                          RTLIB::Libcall LC) {
-  return MO.isSymbol() && TLI.getLibcallName(LC) == MO.getSymbolName();
+  return MO.isSymbol() &&
+         StringRef(TLI.getLibcallName(LC)) == MO.getSymbolName();
 }
 
 bool isVGInstruction(MachineBasicBlock::iterator MBBI,

>From 80b7661434b5809e9702a0622d254f8f6aa3f63c Mon Sep 17 00:00:00 2001
From: Benjamin Maxwell <benjamin.maxwell at arm.com>
Date: Wed, 13 Aug 2025 18:16:04 +0000
Subject: [PATCH 5/8] Check prefix

---
 llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
index 86ef0e0058263..7ccb7f2a4806b 100644
--- a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
+++ b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
@@ -81,6 +81,10 @@ SMEAttrs::SMEAttrs(const AttributeList &Attrs) {
 
 void SMEAttrs::addKnownFunctionAttrs(StringRef FuncName,
                                      const TargetLowering &TLI) {
+  // Skip functions that do not appear to be builtins (starting with "__").
+  if (!FuncName.starts_with('_'))
+    return;
+
   struct SMERoutineAttr {
     RTLIB::Libcall LC{RTLIB::UNKNOWN_LIBCALL};
     unsigned Attrs{SMEAttrs::Normal};

>From 00d1d91f75daf2ca46d2005643709ff373082c45 Mon Sep 17 00:00:00 2001
From: Benjamin Maxwell <benjamin.maxwell at arm.com>
Date: Wed, 13 Aug 2025 18:33:31 +0000
Subject: [PATCH 6/8] Revert "Check prefix"

This reverts commit 1da81a040218b5ef20e0f7d12c6d0088158abb51.
---
 llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
index 7ccb7f2a4806b..86ef0e0058263 100644
--- a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
+++ b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
@@ -81,10 +81,6 @@ SMEAttrs::SMEAttrs(const AttributeList &Attrs) {
 
 void SMEAttrs::addKnownFunctionAttrs(StringRef FuncName,
                                      const TargetLowering &TLI) {
-  // Skip functions that do not appear to be builtins (starting with "__").
-  if (!FuncName.starts_with('_'))
-    return;
-
   struct SMERoutineAttr {
     RTLIB::Libcall LC{RTLIB::UNKNOWN_LIBCALL};
     unsigned Attrs{SMEAttrs::Normal};

>From 9f9497c40c43c7f425cf01ed3c8c4c2cc2fa0f41 Mon Sep 17 00:00:00 2001
From: Benjamin Maxwell <benjamin.maxwell at arm.com>
Date: Wed, 13 Aug 2025 20:24:24 +0000
Subject: [PATCH 7/8] Check prefix

---
 .../lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp | 11 +++++------
 llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h  | 11 ++++++++++-
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
index 86ef0e0058263..90ab5e0fbc456 100644
--- a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
+++ b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
@@ -14,12 +14,7 @@
 
 using namespace llvm;
 
-void SMEAttrs::set(unsigned M, bool Enable) {
-  if (Enable)
-    Bitmask |= M;
-  else
-    Bitmask &= ~M;
-
+void SMEAttrs::validate() const {
   // Streaming Mode Attrs
   assert(!(hasStreamingInterface() && hasStreamingCompatibleInterface()) &&
          "SM_Enabled and SM_Compatible are mutually exclusive");
@@ -81,6 +76,10 @@ SMEAttrs::SMEAttrs(const AttributeList &Attrs) {
 
 void SMEAttrs::addKnownFunctionAttrs(StringRef FuncName,
                                      const TargetLowering &TLI) {
+  // If the function name does not start with a _ or #_ is not a builtin.
+  if (!FuncName.starts_with('_') && !FuncName.starts_with("#_"))
+    return;
+
   struct SMERoutineAttr {
     RTLIB::Libcall LC{RTLIB::UNKNOWN_LIBCALL};
     unsigned Attrs{SMEAttrs::Normal};
diff --git a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h
index bfbb5deec50bd..fee3a29cdece8 100644
--- a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h
+++ b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h
@@ -62,7 +62,15 @@ class SMEAttrs {
     addKnownFunctionAttrs(FuncName, TLI);
   };
 
-  void set(unsigned M, bool Enable = true);
+  void set(unsigned M, bool Enable = true) {
+    if (Enable)
+      Bitmask |= M;
+    else
+      Bitmask &= ~M;
+#ifndef NDEBUG
+    validate();
+#endif
+  }
 
   // Interfaces to query PSTATE.SM
   bool hasStreamingBody() const { return Bitmask & SM_Body; }
@@ -149,6 +157,7 @@ class SMEAttrs {
 
 private:
   void addKnownFunctionAttrs(StringRef FuncName, const TargetLowering &TLI);
+  void validate() const;
 };
 
 /// SMECallAttrs is a utility class to hold the SMEAttrs for a callsite. It has

>From 8235c92c0b0b8c62227d4290a663f6dbbb2aa084 Mon Sep 17 00:00:00 2001
From: Benjamin Maxwell <benjamin.maxwell at arm.com>
Date: Fri, 15 Aug 2025 07:55:05 +0000
Subject: [PATCH 8/8] Re-try getSupportedLibcallImpl

---
 .../AArch64/Utils/AArch64SMEAttributes.cpp    | 60 ++++++++-----------
 .../AArch64/Utils/AArch64SMEAttributes.h      |  2 +-
 2 files changed, 26 insertions(+), 36 deletions(-)

diff --git a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
index 90ab5e0fbc456..fd2243eb7f09b 100644
--- a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
+++ b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.cpp
@@ -76,44 +76,34 @@ SMEAttrs::SMEAttrs(const AttributeList &Attrs) {
 
 void SMEAttrs::addKnownFunctionAttrs(StringRef FuncName,
                                      const TargetLowering &TLI) {
-  // If the function name does not start with a _ or #_ is not a builtin.
-  if (!FuncName.starts_with('_') && !FuncName.starts_with("#_"))
+  RTLIB::LibcallImpl Impl = TLI.getSupportedLibcallImpl(FuncName);
+  if (Impl == RTLIB::Unsupported)
     return;
-
-  struct SMERoutineAttr {
-    RTLIB::Libcall LC{RTLIB::UNKNOWN_LIBCALL};
-    unsigned Attrs{SMEAttrs::Normal};
-  };
-
-  static constexpr unsigned SMCompatiableABIRoutine =
-      SMEAttrs::SM_Compatible | SMEAttrs::SME_ABI_Routine;
-  static constexpr unsigned SMCompatiableABIRoutineInZA =
-      SMCompatiableABIRoutine | encodeZAState(StateValue::In);
-
-  // Table of SME routine -> Known attributes.
-  static constexpr SMERoutineAttr SMERoutineAttrs[]{
-      {RTLIB::SMEABI_SME_STATE, SMCompatiableABIRoutine},
-      {RTLIB::SMEABI_TPIDR2_SAVE, SMCompatiableABIRoutine},
-      {RTLIB::SMEABI_GET_CURRENT_VG, SMCompatiableABIRoutine},
-      {RTLIB::SMEABI_SME_STATE_SIZE, SMCompatiableABIRoutine},
-      {RTLIB::SMEABI_SME_SAVE, SMCompatiableABIRoutine},
-      {RTLIB::SMEABI_SME_RESTORE, SMCompatiableABIRoutine},
-      {RTLIB::SMEABI_ZA_DISABLE, SMCompatiableABIRoutineInZA},
-      {RTLIB::SMEABI_TPIDR2_RESTORE, SMCompatiableABIRoutineInZA},
-      {RTLIB::SC_MEMCPY, SMEAttrs::SM_Compatible},
-      {RTLIB::SC_MEMMOVE, SMEAttrs::SM_Compatible},
-      {RTLIB::SC_MEMSET, SMEAttrs::SM_Compatible},
-      {RTLIB::SC_MEMCHR, SMEAttrs::SM_Compatible},
-  };
-
   unsigned KnownAttrs = SMEAttrs::Normal;
-  for (auto [LC, Attrs] : SMERoutineAttrs) {
-    if (TLI.getLibcallName(LC) == FuncName) {
-      KnownAttrs = Attrs;
-      break;
-    }
+  RTLIB::Libcall LC = RTLIB::RuntimeLibcallsInfo::getLibcallFromImpl(Impl);
+  switch (LC) {
+  case RTLIB::SMEABI_SME_STATE:
+  case RTLIB::SMEABI_TPIDR2_SAVE:
+  case RTLIB::SMEABI_GET_CURRENT_VG:
+  case RTLIB::SMEABI_SME_STATE_SIZE:
+  case RTLIB::SMEABI_SME_SAVE:
+  case RTLIB::SMEABI_SME_RESTORE:
+    KnownAttrs |= SMEAttrs::SM_Compatible | SMEAttrs::SME_ABI_Routine;
+    break;
+  case RTLIB::SMEABI_ZA_DISABLE:
+  case RTLIB::SMEABI_TPIDR2_RESTORE:
+    KnownAttrs |= SMEAttrs::SM_Compatible | encodeZAState(StateValue::In) |
+                  SMEAttrs::SME_ABI_Routine;
+    break;
+  case RTLIB::SC_MEMCPY:
+  case RTLIB::SC_MEMMOVE:
+  case RTLIB::SC_MEMSET:
+  case RTLIB::SC_MEMCHR:
+    KnownAttrs |= SMEAttrs::SM_Compatible;
+    break;
+  default:
+    break;
   }
-
   set(KnownAttrs);
 }
 
diff --git a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h
index fee3a29cdece8..851436e3b7cce 100644
--- a/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h
+++ b/llvm/lib/Target/AArch64/Utils/AArch64SMEAttributes.h
@@ -92,7 +92,7 @@ class SMEAttrs {
   static StateValue decodeZAState(unsigned Bitmask) {
     return static_cast<StateValue>((Bitmask & ZA_Mask) >> ZA_Shift);
   }
-  static constexpr unsigned encodeZAState(StateValue S) {
+  static unsigned encodeZAState(StateValue S) {
     return static_cast<unsigned>(S) << ZA_Shift;
   }
 



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