[NFC][Clang][FMV] Make FMV priority data type future proof. (llvm#150079)

labrinea · mahesh-attarde · commit 40e2bc7cd87b · 2025-07-28T04:21:08.000-07:00
FMV priority is the returned value of a polymorphic function. On RISC-V
and X86 targets a 32-bit value is enough. On AArch64 we currently need
64 bits and we will soon exceed that. APInt seems to be a suitable
replacement for uint64_t, presumably with minimal compile time overhead.
It allows bit manipulation, comparison and variable bit width.
diff --git a/clang/include/clang/Basic/TargetInfo.h b/clang/include/clang/Basic/TargetInfo.h
@@ -1551,8 +1551,8 @@ class TargetInfo : public TransferrableTargetInfo,
 
   // Return the target-specific priority for features/cpus/vendors so
   // that they can be properly sorted for checking.
-  virtual uint64_t getFMVPriority(ArrayRef<StringRef> Features) const {
-    return 0;
+  virtual llvm::APInt getFMVPriority(ArrayRef<StringRef> Features) const {
+    return llvm::APInt::getZero(32);
   }
 
   // Validate the contents of the __builtin_cpu_is(const char*)
diff --git a/clang/lib/Basic/Targets/AArch64.cpp b/clang/lib/Basic/Targets/AArch64.cpp
@@ -786,7 +786,8 @@ AArch64TargetInfo::getVScaleRange(const LangOptions &LangOpts,
   return std::nullopt;
 }
 
-uint64_t AArch64TargetInfo::getFMVPriority(ArrayRef<StringRef> Features) const {
+llvm::APInt
+AArch64TargetInfo::getFMVPriority(ArrayRef<StringRef> Features) const {
   return llvm::AArch64::getFMVPriority(Features);
 }
 
diff --git a/clang/lib/Basic/Targets/AArch64.h b/clang/lib/Basic/Targets/AArch64.h
@@ -152,7 +152,7 @@ class LLVM_LIBRARY_VISIBILITY AArch64TargetInfo : public TargetInfo {
   void fillValidCPUList(SmallVectorImpl<StringRef> &Values) const override;
   bool setCPU(const std::string &Name) override;
 
-  uint64_t getFMVPriority(ArrayRef<StringRef> Features) const override;
+  llvm::APInt getFMVPriority(ArrayRef<StringRef> Features) const override;
 
   bool useFP16ConversionIntrinsics() const override {
     return false;
diff --git a/clang/lib/Basic/Targets/RISCV.cpp b/clang/lib/Basic/Targets/RISCV.cpp
@@ -568,7 +568,8 @@ ParsedTargetAttr RISCVTargetInfo::parseTargetAttr(StringRef Features) const {
   return Ret;
 }
 
-uint64_t RISCVTargetInfo::getFMVPriority(ArrayRef<StringRef> Features) const {
+llvm::APInt
+RISCVTargetInfo::getFMVPriority(ArrayRef<StringRef> Features) const {
   // Priority is explicitly specified on RISC-V unlike on other targets, where
   // it is derived by all the features of a specific version. Therefore if a
   // feature contains the priority string, then return it immediately.
@@ -580,12 +581,12 @@ uint64_t RISCVTargetInfo::getFMVPriority(ArrayRef<StringRef> Features) const {
       Feature = RHS;
     else
       continue;
-    uint64_t Priority;
+    unsigned Priority;
     if (!Feature.getAsInteger(0, Priority))
-      return Priority;
+      return llvm::APInt(32, Priority);
   }
   // Default Priority is zero.
-  return 0;
+  return llvm::APInt::getZero(32);
 }
 
 TargetInfo::CallingConvCheckResult
diff --git a/clang/lib/Basic/Targets/RISCV.h b/clang/lib/Basic/Targets/RISCV.h
@@ -123,7 +123,7 @@ class RISCVTargetInfo : public TargetInfo {
   void fillValidTuneCPUList(SmallVectorImpl<StringRef> &Values) const override;
   bool supportsTargetAttributeTune() const override { return true; }
   ParsedTargetAttr parseTargetAttr(StringRef Str) const override;
-  uint64_t getFMVPriority(ArrayRef<StringRef> Features) const override;
+  llvm::APInt getFMVPriority(ArrayRef<StringRef> Features) const override;
 
   std::pair<unsigned, unsigned> hardwareInterferenceSizes() const override {
     return std::make_pair(32, 32);
diff --git a/clang/lib/Basic/Targets/X86.cpp b/clang/lib/Basic/Targets/X86.cpp
@@ -1390,8 +1390,8 @@ static llvm::X86::ProcessorFeatures getFeature(StringRef Name) {
   // correct, so it asserts if the value is out of range.
 }
 
-uint64_t X86TargetInfo::getFMVPriority(ArrayRef<StringRef> Features) const {
-  auto getPriority = [](StringRef Feature) -> uint64_t {
+llvm::APInt X86TargetInfo::getFMVPriority(ArrayRef<StringRef> Features) const {
+  auto getPriority = [](StringRef Feature) -> unsigned {
     // Valid CPUs have a 'key feature' that compares just better than its key
     // feature.
     using namespace llvm::X86;
@@ -1405,11 +1405,11 @@ uint64_t X86TargetInfo::getFMVPriority(ArrayRef<StringRef> Features) const {
     return getFeaturePriority(getFeature(Feature)) << 1;
   };
 
-  uint64_t Priority = 0;
+  unsigned Priority = 0;
   for (StringRef Feature : Features)
     if (!Feature.empty())
       Priority = std::max(Priority, getPriority(Feature));
-  return Priority;
+  return llvm::APInt(32, Priority);
 }
 
 bool X86TargetInfo::validateCPUSpecificCPUDispatch(StringRef Name) const {
diff --git a/clang/lib/Basic/Targets/X86.h b/clang/lib/Basic/Targets/X86.h
@@ -388,7 +388,7 @@ class LLVM_LIBRARY_VISIBILITY X86TargetInfo : public TargetInfo {
     return CPU != llvm::X86::CK_None;
   }
 
-  uint64_t getFMVPriority(ArrayRef<StringRef> Features) const override;
+  llvm::APInt getFMVPriority(ArrayRef<StringRef> Features) const override;
 
   bool setFPMath(StringRef Name) override;
 
diff --git a/clang/lib/CodeGen/ABIInfo.cpp b/clang/lib/CodeGen/ABIInfo.cpp
@@ -218,8 +218,8 @@ void ABIInfo::appendAttributeMangling(StringRef AttrStr,
     // only have "+" prefixes here.
     assert(LHS.starts_with("+") && RHS.starts_with("+") &&
            "Features should always have a prefix.");
-    return TI.getFMVPriority({LHS.substr(1)}) >
-           TI.getFMVPriority({RHS.substr(1)});
+    return TI.getFMVPriority({LHS.substr(1)})
+        .ugt(TI.getFMVPriority({RHS.substr(1)}));
   });
 
   bool IsFirst = true;
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -4418,8 +4418,9 @@ void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD, llvm::GlobalValue *GV) {
 static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old,
                                                       llvm::Function *NewFn);
 
-static uint64_t getFMVPriority(const TargetInfo &TI,
-                               const CodeGenFunction::FMVResolverOption &RO) {
+static llvm::APInt
+getFMVPriority(const TargetInfo &TI,
+               const CodeGenFunction::FMVResolverOption &RO) {
   llvm::SmallVector<StringRef, 8> Features{RO.Features};
   if (RO.Architecture)
     Features.push_back(*RO.Architecture);
@@ -4544,7 +4545,7 @@ void CodeGenModule::emitMultiVersionFunctions() {
     llvm::stable_sort(
         Options, [&TI](const CodeGenFunction::FMVResolverOption &LHS,
                        const CodeGenFunction::FMVResolverOption &RHS) {
-          return getFMVPriority(TI, LHS) > getFMVPriority(TI, RHS);
+          return getFMVPriority(TI, LHS).ugt(getFMVPriority(TI, RHS));
         });
     CodeGenFunction CGF(*this);
     CGF.EmitMultiVersionResolver(ResolverFunc, Options);
diff --git a/clang/lib/CodeGen/TargetBuiltins/ARM.cpp b/clang/lib/CodeGen/TargetBuiltins/ARM.cpp
@@ -8112,7 +8112,7 @@ Value *CodeGenFunction::EmitAArch64CpuSupports(const CallExpr *E) {
 
 llvm::Value *
 CodeGenFunction::EmitAArch64CpuSupports(ArrayRef<StringRef> FeaturesStrs) {
-  uint64_t FeaturesMask = llvm::AArch64::getCpuSupportsMask(FeaturesStrs);
+  llvm::APInt FeaturesMask = llvm::AArch64::getCpuSupportsMask(FeaturesStrs);
   Value *Result = Builder.getTrue();
   if (FeaturesMask != 0) {
     // Get features from structure in runtime library
@@ -8128,7 +8128,7 @@ CodeGenFunction::EmitAArch64CpuSupports(ArrayRef<StringRef> FeaturesStrs) {
         {ConstantInt::get(Int32Ty, 0), ConstantInt::get(Int32Ty, 0)});
     Value *Features = Builder.CreateAlignedLoad(Int64Ty, CpuFeatures,
                                                 CharUnits::fromQuantity(8));
-    Value *Mask = Builder.getInt64(FeaturesMask);
+    Value *Mask = Builder.getInt(FeaturesMask.trunc(64));
     Value *Bitset = Builder.CreateAnd(Features, Mask);
     Value *Cmp = Builder.CreateICmpEQ(Bitset, Mask);
     Result = Builder.CreateAnd(Result, Cmp);
diff --git a/llvm/include/llvm/Analysis/TargetTransformInfo.h b/llvm/include/llvm/Analysis/TargetTransformInfo.h
@@ -1930,7 +1930,7 @@ class TargetTransformInfo {
 
   /// Returns a bitmask constructed from the target-features or fmv-features
   /// metadata of a function.
-  LLVM_ABI uint64_t getFeatureMask(const Function &F) const;
+  LLVM_ABI APInt getFeatureMask(const Function &F) const;
 
   /// Returns true if this is an instance of a function with multiple versions.
   LLVM_ABI bool isMultiversionedFunction(const Function &F) const;
diff --git a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
@@ -1126,7 +1126,9 @@ class TargetTransformInfoImplBase {
 
   virtual bool hasArmWideBranch(bool) const { return false; }
 
-  virtual uint64_t getFeatureMask(const Function &F) const { return 0; }
+  virtual APInt getFeatureMask(const Function &F) const {
+    return APInt::getZero(32);
+  }
 
   virtual bool isMultiversionedFunction(const Function &F) const {
     return false;
diff --git a/llvm/include/llvm/TargetParser/AArch64TargetParser.h b/llvm/include/llvm/TargetParser/AArch64TargetParser.h
@@ -276,14 +276,14 @@ LLVM_ABI bool isX18ReservedByDefault(const Triple &TT);
 // For a given set of feature names, which can be either target-features, or
 // fmv-features metadata, expand their dependencies and then return a bitmask
 // corresponding to the entries of AArch64::FeatPriorities.
-LLVM_ABI uint64_t getFMVPriority(ArrayRef<StringRef> Features);
+LLVM_ABI APInt getFMVPriority(ArrayRef<StringRef> Features);
 
 // For a given set of FMV feature names, expand their dependencies and then
 // return a bitmask corresponding to the entries of AArch64::CPUFeatures.
 // The values in CPUFeatures are not bitmasks themselves, they are sequential
 // (0, 1, 2, 3, ...). The resulting bitmask is used at runtime to test whether
 // a certain FMV feature is available on the host.
-LLVM_ABI uint64_t getCpuSupportsMask(ArrayRef<StringRef> Features);
+LLVM_ABI APInt getCpuSupportsMask(ArrayRef<StringRef> Features);
 
 LLVM_ABI void PrintSupportedExtensions();
 
diff --git a/llvm/lib/Analysis/TargetTransformInfo.cpp b/llvm/lib/Analysis/TargetTransformInfo.cpp
@@ -1423,7 +1423,7 @@ bool TargetTransformInfo::hasArmWideBranch(bool Thumb) const {
   return TTIImpl->hasArmWideBranch(Thumb);
 }
 
-uint64_t TargetTransformInfo::getFeatureMask(const Function &F) const {
+APInt TargetTransformInfo::getFeatureMask(const Function &F) const {
   return TTIImpl->getFeatureMask(F);
 }
 
diff --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp
@@ -249,7 +249,7 @@ static bool hasPossibleIncompatibleOps(const Function *F) {
   return false;
 }
 
-uint64_t AArch64TTIImpl::getFeatureMask(const Function &F) const {
+APInt AArch64TTIImpl::getFeatureMask(const Function &F) const {
   StringRef AttributeStr =
       isMultiversionedFunction(F) ? "fmv-features" : "target-features";
   StringRef FeatureStr = F.getFnAttribute(AttributeStr).getValueAsString();
diff --git a/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h b/llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h
@@ -89,7 +89,7 @@ class AArch64TTIImpl final : public BasicTTIImplBase<AArch64TTIImpl> {
   unsigned getInlineCallPenalty(const Function *F, const CallBase &Call,
                                 unsigned DefaultCallPenalty) const override;
 
-  uint64_t getFeatureMask(const Function &F) const override;
+  APInt getFeatureMask(const Function &F) const override;
 
   bool isMultiversionedFunction(const Function &F) const override;
 
diff --git a/llvm/lib/TargetParser/AArch64TargetParser.cpp b/llvm/lib/TargetParser/AArch64TargetParser.cpp
@@ -55,7 +55,7 @@ std::optional<AArch64::FMVInfo> lookupFMVByID(AArch64::ArchExtKind ExtID) {
   return {};
 }
 
-uint64_t AArch64::getFMVPriority(ArrayRef<StringRef> Features) {
+APInt AArch64::getFMVPriority(ArrayRef<StringRef> Features) {
   // Transitively enable the Arch Extensions which correspond to each feature.
   ExtensionSet FeatureBits;
   for (const StringRef Feature : Features) {
@@ -69,15 +69,15 @@ uint64_t AArch64::getFMVPriority(ArrayRef<StringRef> Features) {
   }
 
   // Construct a bitmask for all the transitively enabled Arch Extensions.
-  uint64_t PriorityMask = 0;
+  APInt PriorityMask = APInt::getZero(128);
   for (const FMVInfo &Info : getFMVInfo())
     if (Info.ID && FeatureBits.Enabled.test(*Info.ID))
-      PriorityMask |= (1ULL << Info.PriorityBit);
+      PriorityMask.setBit(Info.PriorityBit);
 
   return PriorityMask;
 }
 
-uint64_t AArch64::getCpuSupportsMask(ArrayRef<StringRef> Features) {
+APInt AArch64::getCpuSupportsMask(ArrayRef<StringRef> Features) {
   // Transitively enable the Arch Extensions which correspond to each feature.
   ExtensionSet FeatureBits;
   for (const StringRef Feature : Features)
@@ -86,10 +86,10 @@ uint64_t AArch64::getCpuSupportsMask(ArrayRef<StringRef> Features) {
         FeatureBits.enable(*Info->ID);
 
   // Construct a bitmask for all the transitively enabled Arch Extensions.
-  uint64_t FeaturesMask = 0;
+  APInt FeaturesMask = APInt::getZero(128);
   for (const FMVInfo &Info : getFMVInfo())
     if (Info.ID && FeatureBits.Enabled.test(*Info.ID))
-      FeaturesMask |= (1ULL << Info.FeatureBit);
+      FeaturesMask.setBit(Info.FeatureBit);
 
   return FeaturesMask;
 }
diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -2529,7 +2529,7 @@ static bool OptimizeNonTrivialIFuncs(
   bool Changed = false;
 
   // Cache containing the mask constructed from a function's target features.
-  DenseMap<Function *, uint64_t> FeatureMask;
+  DenseMap<Function *, APInt> FeatureMask;
 
   for (GlobalIFunc &IF : M.ifuncs()) {
     if (IF.isInterposable())
@@ -2568,7 +2568,7 @@ static bool OptimizeNonTrivialIFuncs(
 
     // Sort the callee versions in decreasing priority order.
     sort(Callees, [&](auto *LHS, auto *RHS) {
-      return FeatureMask[LHS] > FeatureMask[RHS];
+      return FeatureMask[LHS].ugt(FeatureMask[RHS]);
     });
 
     // Find the callsites and cache the feature mask for each caller.
@@ -2591,10 +2591,10 @@ static bool OptimizeNonTrivialIFuncs(
 
     // Sort the caller versions in decreasing priority order.
     sort(Callers, [&](auto *LHS, auto *RHS) {
-      return FeatureMask[LHS] > FeatureMask[RHS];
+      return FeatureMask[LHS].ugt(FeatureMask[RHS]);
     });
 
-    auto implies = [](uint64_t A, uint64_t B) { return (A & B) == B; };
+    auto implies = [](APInt A, APInt B) { return B.isSubsetOf(A); };
 
     // Index to the highest priority candidate.
     unsigned I = 0;
@@ -2603,8 +2603,8 @@ static bool OptimizeNonTrivialIFuncs(
       assert(I < Callees.size() && "Found callers of equal priority");
 
       Function *Callee = Callees[I];
-      uint64_t CallerBits = FeatureMask[Caller];
-      uint64_t CalleeBits = FeatureMask[Callee];
+      APInt CallerBits = FeatureMask[Caller];
+      APInt CalleeBits = FeatureMask[Callee];
 
       // In the case of FMV callers, we know that all higher priority callers
       // than the current one did not get selected at runtime, which helps

Original file line number	Diff line number	Diff line change
`@@ -1551,8 +1551,8 @@ class TargetInfo : public TransferrableTargetInfo,`
`1551`	`1551`
`1552`	`1552`	`// Return the target-specific priority for features/cpus/vendors so`
`1553`	`1553`	`// that they can be properly sorted for checking.`
`1554`		`- virtual uint64_t getFMVPriority(ArrayRef<StringRef> Features) const {`
`1555`		`- return 0;`
	`1554`	`+ virtual llvm::APInt getFMVPriority(ArrayRef<StringRef> Features) const {`
	`1555`	`+ return llvm::APInt::getZero(32);`
`1556`	`1556`	`}`
`1557`	`1557`
`1558`	`1558`	`// Validate the contents of the __builtin_cpu_is(const char*)`
Original file line number	Diff line number	Diff line change
`@@ -786,7 +786,8 @@ AArch64TargetInfo::getVScaleRange(const LangOptions &LangOpts,`
`786`	`786`	`return std::nullopt;`
`787`	`787`	`}`
`788`	`788`
`789`		`-uint64_t AArch64TargetInfo::getFMVPriority(ArrayRef<StringRef> Features) const {`
	`789`	`+llvm::APInt`
	`790`	`+AArch64TargetInfo::getFMVPriority(ArrayRef<StringRef> Features) const {`
`790`	`791`	`return llvm::AArch64::getFMVPriority(Features);`
`791`	`792`	`}`
`792`	`793`
Original file line number	Diff line number	Diff line change
`@@ -388,7 +388,7 @@ class LLVM_LIBRARY_VISIBILITY X86TargetInfo : public TargetInfo {`
`388`	`388`	`return CPU != llvm::X86::CK_None;`
`389`	`389`	`}`
`390`	`390`
`391`		`- uint64_t getFMVPriority(ArrayRef<StringRef> Features) const override;`
	`391`	`+ llvm::APInt getFMVPriority(ArrayRef<StringRef> Features) const override;`
`392`	`392`
`393`	`393`	`bool setFPMath(StringRef Name) override;`
`394`	`394`