[FMV][AArch64] Allow user to override version priority.

clang/lib/CodeGen/Targets/AArch64.cpp

@@ -1336,10 +1336,13 @@ void AArch64ABIInfo::appendAttributeMangling(StringRef AttrStr,
   });
 
   llvm::SmallDenseSet<StringRef, 8> UniqueFeats;
-  for (auto &Feat : Features)
+  for (auto &Feat : Features) {
+    if (!getTarget().doesFeatureAffectCodeGen(Feat))
+      continue;
     if (auto Ext = llvm::AArch64::parseFMVExtension(Feat))
       if (UniqueFeats.insert(Ext->Name).second)
         Out << 'M' << Ext->Name;
+  }
 }
 
 std::unique_ptr<TargetCodeGenInfo>

clang/test/CodeGen/AArch64/fmv-duplicate-mangled-name.c

@@ -1,5 +1,7 @@
 // RUN: %clang_cc1 -triple aarch64-linux-gnu -verify -emit-llvm-only %s -DCHECK_IMPLICIT_DEFAULT
 // RUN: %clang_cc1 -triple aarch64-linux-gnu -verify -emit-llvm-only %s -DCHECK_EXPLICIT_DEFAULT
+// RUN: %clang_cc1 -triple aarch64-linux-gnu -verify -emit-llvm-only %s -DCHECK_EXPLICIT_VERSION_PRIORITY
+// RUN: %clang_cc1 -triple aarch64-linux-gnu -verify -emit-llvm-only %s -DCHECK_EXPLICIT_CLONES_PRIORITY
 
 #if defined(CHECK_IMPLICIT_DEFAULT)
 
@@ -21,4 +23,18 @@ __attribute__((target_version("default"))) int explicit_default_bad(void) { retu
 // expected-note@-2 {{previous definition is here}}
 __attribute__((target_clones("aes", "lse", "default"))) int explicit_default_bad(void) { return 1; }
 
+#elif defined(CHECK_EXPLICIT_VERSION_PRIORITY)
+
+__attribute__((target_version("aes"))) int explicit_version_priority(void) { return 0; }
+// expected-error@+2 {{definition with same mangled name 'explicit_version_priority._Maes' as another definition}}
+// expected-note@-2 {{previous definition is here}}
+__attribute__((target_version("priority1+aes"))) int explicit_version_priority(void) { return 1; }
+
+#elif defined(CHECK_EXPLICIT_CLONES_PRIORITY)
+
+__attribute__((target_version("aes+priority2"))) int explicit_clones_priority(void) { return 0; }
+// expected-error@+2 {{definition with same mangled name 'explicit_clones_priority._Maes' as another definition}}
+// expected-note@-2 {{previous definition is here}}
+__attribute__((target_clones("priority1+aes", "lse"))) int explicit_clones_priority(void) { return 1; }
+
 #endif

clang/test/CodeGen/AArch64/fmv-explicit-priority.c

@@ -0,0 +1,193 @@
+// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --function-signature --check-attributes --check-globals --include-generated-funcs
+// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -O3 -fno-inline -emit-llvm -o - %s | FileCheck %s
+
+__attribute__((target_version("priority1+lse"))) int foo(void) { return 1; }
+__attribute__((target_version("priority2+sve2"))) int foo(void) { return 2; }
+__attribute__((target_version("priority3+sve"))) int foo(void) { return 3; }
+__attribute__((target_version( "default"))) int foo(void) { return 0; }
+
+__attribute__((target_clones("priority1+lse+sve2", "priority2+lse", "priority3+sve", "default")))
+int fmv_caller(void) { return foo(); }
+
+
+__attribute__((target_version("aes"))) int bar(void) { return 1; }
+__attribute__((target_version("priority1+sm4"))) int bar(void) { return 2; }
+__attribute__((target_version("default"))) int bar(void) { return 0; }
+
+__attribute__((target("aes"))) int regular_caller_aes() { return bar(); }
+__attribute__((target("sm4"))) int regular_caller_sm4() { return bar(); }
+//.
+// CHECK: @__aarch64_cpu_features = external dso_local local_unnamed_addr global { i64 }
+// CHECK: @foo = weak_odr ifunc i32 (), ptr @foo.resolver
+// CHECK: @fmv_caller = weak_odr ifunc i32 (), ptr @fmv_caller.resolver
+// CHECK: @bar = weak_odr ifunc i32 (), ptr @bar.resolver
+//.
+// CHECK: Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none)
+// CHECK-LABEL: define {{[^@]+}}@foo._Mlse
+// CHECK-SAME: () #[[ATTR0:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    ret i32 1
+//
+//
+// CHECK: Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) vscale_range(1,16)
+// CHECK-LABEL: define {{[^@]+}}@foo._Msve2
+// CHECK-SAME: () #[[ATTR1:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    ret i32 2
+//
+//
+// CHECK: Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) vscale_range(1,16)
+// CHECK-LABEL: define {{[^@]+}}@foo._Msve
+// CHECK-SAME: () #[[ATTR2:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    ret i32 3
+//
+//
+// CHECK: Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none)
+// CHECK-LABEL: define {{[^@]+}}@foo.default
+// CHECK-SAME: () #[[ATTR3:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    ret i32 0
+//
+//
+// CHECK: Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) vscale_range(1,16)
+// CHECK-LABEL: define {{[^@]+}}@fmv_caller._MlseMsve2
+// CHECK-SAME: () #[[ATTR4:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[CALL:%.*]] = tail call i32 @foo._Mlse()
+// CHECK-NEXT:    ret i32 [[CALL]]
+//
+//
+// CHECK: Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) vscale_range(1,16)
+// CHECK-LABEL: define {{[^@]+}}@fmv_caller._Mlse
+// CHECK-SAME: () #[[ATTR5:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[CALL:%.*]] = tail call i32 @foo._Mlse()
+// CHECK-NEXT:    ret i32 [[CALL]]
+//
+//
+// CHECK: Function Attrs: noinline nounwind vscale_range(1,16)
+// CHECK-LABEL: define {{[^@]+}}@fmv_caller._Msve
+// CHECK-SAME: () #[[ATTR6:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[CALL:%.*]] = tail call i32 @foo() #[[ATTR12:[0-9]+]]
+// CHECK-NEXT:    ret i32 [[CALL]]
+//
+//
+// CHECK: Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) vscale_range(1,16)
+// CHECK-LABEL: define {{[^@]+}}@fmv_caller.default
+// CHECK-SAME: () #[[ATTR7:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[CALL:%.*]] = tail call i32 @foo.default()
+// CHECK-NEXT:    ret i32 [[CALL]]
+//
+//
+// CHECK: Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none)
+// CHECK-LABEL: define {{[^@]+}}@bar._Maes
+// CHECK-SAME: () #[[ATTR8:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    ret i32 1
+//
+//
+// CHECK: Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none)
+// CHECK-LABEL: define {{[^@]+}}@bar._Msm4
+// CHECK-SAME: () #[[ATTR9:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    ret i32 2
+//
+//
+// CHECK: Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none)
+// CHECK-LABEL: define {{[^@]+}}@bar.default
+// CHECK-SAME: () #[[ATTR3]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    ret i32 0
+//
+//
+// CHECK: Function Attrs: noinline nounwind
+// CHECK-LABEL: define {{[^@]+}}@regular_caller_aes
+// CHECK-SAME: () local_unnamed_addr #[[ATTR10:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[CALL:%.*]] = tail call i32 @bar() #[[ATTR12]]
+// CHECK-NEXT:    ret i32 [[CALL]]
+//
+//
+// CHECK: Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none)
+// CHECK-LABEL: define {{[^@]+}}@regular_caller_sm4
+// CHECK-SAME: () local_unnamed_addr #[[ATTR11:[0-9]+]] {
+// CHECK-NEXT:  entry:
+// CHECK-NEXT:    [[CALL:%.*]] = tail call i32 @bar._Msm4()
+// CHECK-NEXT:    ret i32 [[CALL]]
+//
+//
+// CHECK-LABEL: define {{[^@]+}}@foo.resolver() comdat {
+// CHECK-NEXT:  resolver_entry:
+// CHECK-NEXT:    tail call void @__init_cpu_features_resolver()
+// CHECK-NEXT:    [[TMP0:%.*]] = load i64, ptr @__aarch64_cpu_features, align 8
+// CHECK-NEXT:    [[TMP1:%.*]] = and i64 [[TMP0]], 128
+// CHECK-NEXT:    [[DOTNOT:%.*]] = icmp eq i64 [[TMP1]], 0
+// CHECK-NEXT:    br i1 [[DOTNOT]], label [[RESOLVER_ELSE:%.*]], label [[COMMON_RET:%.*]]
+// CHECK:       common.ret:
+// CHECK-NEXT:    [[COMMON_RET_OP:%.*]] = phi ptr [ @foo._Mlse, [[RESOLVER_ENTRY:%.*]] ], [ @foo._Msve2, [[RESOLVER_ELSE]] ], [ [[FOO__MSVE_FOO_DEFAULT:%.*]], [[RESOLVER_ELSE2:%.*]] ]
+// CHECK-NEXT:    ret ptr [[COMMON_RET_OP]]
+// CHECK:       resolver_else:
+// CHECK-NEXT:    [[TMP2:%.*]] = and i64 [[TMP0]], 69793284352
+// CHECK-NEXT:    [[TMP3:%.*]] = icmp eq i64 [[TMP2]], 69793284352
+// CHECK-NEXT:    br i1 [[TMP3]], label [[COMMON_RET]], label [[RESOLVER_ELSE2]]
+// CHECK:       resolver_else2:
+// CHECK-NEXT:    [[TMP4:%.*]] = and i64 [[TMP0]], 1073807616
+// CHECK-NEXT:    [[TMP5:%.*]] = icmp eq i64 [[TMP4]], 1073807616
+// CHECK-NEXT:    [[FOO__MSVE_FOO_DEFAULT]] = select i1 [[TMP5]], ptr @foo._Msve, ptr @foo.default
+// CHECK-NEXT:    br label [[COMMON_RET]]
+//
+//
+// CHECK-LABEL: define {{[^@]+}}@fmv_caller.resolver() comdat {
+// CHECK-NEXT:  resolver_entry:
+// CHECK-NEXT:    tail call void @__init_cpu_features_resolver()
+// CHECK-NEXT:    [[TMP0:%.*]] = load i64, ptr @__aarch64_cpu_features, align 8
+// CHECK-NEXT:    [[TMP1:%.*]] = and i64 [[TMP0]], 69793284480
+// CHECK-NEXT:    [[TMP2:%.*]] = icmp eq i64 [[TMP1]], 69793284480
+// CHECK-NEXT:    br i1 [[TMP2]], label [[COMMON_RET:%.*]], label [[RESOLVER_ELSE:%.*]]
+// CHECK:       common.ret:
+// CHECK-NEXT:    [[COMMON_RET_OP:%.*]] = phi ptr [ @fmv_caller._MlseMsve2, [[RESOLVER_ENTRY:%.*]] ], [ @fmv_caller._Mlse, [[RESOLVER_ELSE]] ], [ [[FMV_CALLER__MSVE_FMV_CALLER_DEFAULT:%.*]], [[RESOLVER_ELSE2:%.*]] ]
+// CHECK-NEXT:    ret ptr [[COMMON_RET_OP]]
+// CHECK:       resolver_else:
+// CHECK-NEXT:    [[TMP3:%.*]] = and i64 [[TMP0]], 128
+// CHECK-NEXT:    [[DOTNOT:%.*]] = icmp eq i64 [[TMP3]], 0
+// CHECK-NEXT:    br i1 [[DOTNOT]], label [[RESOLVER_ELSE2]], label [[COMMON_RET]]
+// CHECK:       resolver_else2:
+// CHECK-NEXT:    [[TMP4:%.*]] = and i64 [[TMP0]], 1073807616
+// CHECK-NEXT:    [[TMP5:%.*]] = icmp eq i64 [[TMP4]], 1073807616
+// CHECK-NEXT:    [[FMV_CALLER__MSVE_FMV_CALLER_DEFAULT]] = select i1 [[TMP5]], ptr @fmv_caller._Msve, ptr @fmv_caller.default
+// CHECK-NEXT:    br label [[COMMON_RET]]
+//
+//
+// CHECK-LABEL: define {{[^@]+}}@bar.resolver() comdat {
+// CHECK-NEXT:  resolver_entry:
+// CHECK-NEXT:    tail call void @__init_cpu_features_resolver()
+// CHECK-NEXT:    [[TMP0:%.*]] = load i64, ptr @__aarch64_cpu_features, align 8
+// CHECK-NEXT:    [[TMP1:%.*]] = and i64 [[TMP0]], 800
+// CHECK-NEXT:    [[TMP2:%.*]] = icmp eq i64 [[TMP1]], 800
+// CHECK-NEXT:    [[TMP3:%.*]] = and i64 [[TMP0]], 33536
+// CHECK-NEXT:    [[TMP4:%.*]] = icmp eq i64 [[TMP3]], 33536
+// CHECK-NEXT:    [[BAR__MAES_BAR_DEFAULT:%.*]] = select i1 [[TMP4]], ptr @bar._Maes, ptr @bar.default
+// CHECK-NEXT:    [[COMMON_RET_OP:%.*]] = select i1 [[TMP2]], ptr @bar._Msm4, ptr [[BAR__MAES_BAR_DEFAULT]]
+// CHECK-NEXT:    ret ptr [[COMMON_RET_OP]]
+//
+//.
+// CHECK: attributes #[[ATTR0]] = { mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) "fmv-features"="lse,priority1" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+lse" }
+// CHECK: attributes #[[ATTR1]] = { mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) vscale_range(1,16) "fmv-features"="priority2,sve2" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+fp-armv8,+fullfp16,+sve,+sve2" }
+// CHECK: attributes #[[ATTR2]] = { mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) vscale_range(1,16) "fmv-features"="priority3,sve" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+fp-armv8,+fullfp16,+sve" }
+// CHECK: attributes #[[ATTR3]] = { mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) "fmv-features" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
+// CHECK: attributes #[[ATTR4]] = { mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) vscale_range(1,16) "fmv-features"="lse,priority1,sve2" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+fp-armv8,+fullfp16,+lse,+sve,+sve2" }
+// CHECK: attributes #[[ATTR5]] = { mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) vscale_range(1,16) "fmv-features"="lse,priority2" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+lse" }
+// CHECK: attributes #[[ATTR6]] = { noinline nounwind vscale_range(1,16) "fmv-features"="priority3,sve" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+fp-armv8,+fullfp16,+sve" }
+// CHECK: attributes #[[ATTR7]] = { mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) vscale_range(1,16) "fmv-features" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
+// CHECK: attributes #[[ATTR8]] = { mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) "fmv-features"="aes" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+aes,+fp-armv8,+neon" }
+// CHECK: attributes #[[ATTR9]] = { mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) "fmv-features"="priority1,sm4" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+fp-armv8,+neon,+sm4" }
+// CHECK: attributes #[[ATTR10]] = { noinline nounwind "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+aes,+fp-armv8,+neon" }
+// CHECK: attributes #[[ATTR11]] = { mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-features"="+fp-armv8,+neon,+sm4" }
+// CHECK: attributes #[[ATTR12]] = { nounwind }
+//.
+// CHECK: [[META0:![0-9]+]] = !{i32 1, !"wchar_size", i32 4}
+// CHECK: [[META1:![0-9]+]] = !{!"{{.*}}clang version {{.*}}"}
+//.

llvm/include/llvm/Analysis/TargetTransformInfo.h

@@ -1916,9 +1916,13 @@ class TargetTransformInfo {
   LLVM_ABI bool hasArmWideBranch(bool Thumb) const;
 
   /// Returns a bitmask constructed from the target-features or fmv-features
-  /// metadata of a function.
+  /// metadata of a function corresponding to its Arch Extensions.
   LLVM_ABI uint64_t getFeatureMask(const Function &F) const;
 
+  /// Returns a bitmask constructed from the target-features or fmv-features
+  /// metadata of a function corresponding to its FMV priority.
+  LLVM_ABI uint64_t getPriorityMask(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;
 

llvm/include/llvm/Analysis/TargetTransformInfoImpl.h

@@ -1126,6 +1126,7 @@ class TargetTransformInfoImplBase {
   virtual bool hasArmWideBranch(bool) const { return false; }
 
   virtual uint64_t getFeatureMask(const Function &F) const { return 0; }
+  virtual uint64_t getPriorityMask(const Function &F) const { return 0; }
 
   virtual bool isMultiversionedFunction(const Function &F) const {
     return false;

llvm/include/llvm/TargetParser/AArch64FeatPriorities.inc

@@ -59,7 +59,12 @@ enum FeatPriorities {
   PRIOR_SME_I64,
   PRIOR_SME2,
   PRIOR_MOPS,
-  PRIOR_CSSC
+  PRIOR_CSSC,
+  PRIOR_5,
+  PRIOR_4,
+  PRIOR_3,
+  PRIOR_2,
+  PRIOR_1
 };
 
 #endif

llvm/lib/Analysis/TargetTransformInfo.cpp

@@ -1426,6 +1426,10 @@ uint64_t TargetTransformInfo::getFeatureMask(const Function &F) const {
   return TTIImpl->getFeatureMask(F);
 }
 
+uint64_t TargetTransformInfo::getPriorityMask(const Function &F) const {
+  return TTIImpl->getPriorityMask(F);
+}
+
 bool TargetTransformInfo::isMultiversionedFunction(const Function &F) const {
   return TTIImpl->isMultiversionedFunction(F);
 }

llvm/lib/Target/AArch64/AArch64FMV.td

@@ -83,3 +83,8 @@ def : FMVExtension<"sve2-sha3", "SVE_SHA3">;
 def : FMVExtension<"sve2-sm4", "SVE_SM4">;
 def : FMVExtension<"wfxt", "WFXT">;
 def : FMVExtension<"cssc", "CSSC">;
+let FeatureBit = "FEAT_MAX" in def : FMVExtension<"priority1", "1">;
+let FeatureBit = "FEAT_MAX" in def : FMVExtension<"priority2", "2">;
+let FeatureBit = "FEAT_MAX" in def : FMVExtension<"priority3", "3">;
+let FeatureBit = "FEAT_MAX" in def : FMVExtension<"priority4", "4">;
+let FeatureBit = "FEAT_MAX" in def : FMVExtension<"priority5", "5">;

llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp

@@ -249,12 +249,23 @@ static bool hasPossibleIncompatibleOps(const Function *F) {
   return false;
 }
 
-uint64_t AArch64TTIImpl::getFeatureMask(const Function &F) const {
+static void extractAttrFeatures(const Function &F, const AArch64TTIImpl *TTI,
+                                SmallVectorImpl<StringRef> &Features) {
   StringRef AttributeStr =
-      isMultiversionedFunction(F) ? "fmv-features" : "target-features";
+      TTI->isMultiversionedFunction(F) ? "fmv-features" : "target-features";
   StringRef FeatureStr = F.getFnAttribute(AttributeStr).getValueAsString();
-  SmallVector<StringRef, 8> Features;
   FeatureStr.split(Features, ",");
+}
+
+uint64_t AArch64TTIImpl::getFeatureMask(const Function &F) const {
+  SmallVector<StringRef, 8> Features;
+  extractAttrFeatures(F, this, Features);
+  return AArch64::getCpuSupportsMask(Features);
+}
+
+uint64_t AArch64TTIImpl::getPriorityMask(const Function &F) const {
+  SmallVector<StringRef, 8> Features;
+  extractAttrFeatures(F, this, Features);
   return AArch64::getFMVPriority(Features);
 }
 

llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h

@@ -92,6 +92,7 @@ class AArch64TTIImpl final : public BasicTTIImplBase<AArch64TTIImpl> {
                                 unsigned DefaultCallPenalty) const override;
 
   uint64_t getFeatureMask(const Function &F) const override;
+  uint64_t getPriorityMask(const Function &F) const override;
 
   bool isMultiversionedFunction(const Function &F) const override;
 

llvm/lib/TargetParser/AArch64TargetParser.cpp

@@ -55,21 +55,30 @@ std::optional<AArch64::FMVInfo> lookupFMVByID(AArch64::ArchExtKind ExtID) {
   return {};
 }
 
+std::optional<AArch64::FMVInfo> getFMVInfoFrom(StringRef Feature) {
+  std::optional<AArch64::FMVInfo> FMV = AArch64::parseFMVExtension(Feature);
+  if (!FMV && Feature.starts_with('+'))
+    if (std::optional<AArch64::ExtensionInfo> Ext =
+            AArch64::targetFeatureToExtension(Feature))
+      FMV = lookupFMVByID(Ext->ID);
+  return FMV;
+}
+
 uint64_t AArch64::getFMVPriority(ArrayRef<StringRef> Features) {
   // Transitively enable the Arch Extensions which correspond to each feature.
   ExtensionSet FeatureBits;
+  uint64_t PriorityMask = 0;
   for (const StringRef Feature : Features) {
-    std::optional<FMVInfo> FMV = parseFMVExtension(Feature);
-    if (!FMV && Feature.starts_with('+')) {
-      if (std::optional<ExtensionInfo> Info = targetFeatureToExtension(Feature))
-        FMV = lookupFMVByID(Info->ID);
+    if (std::optional<FMVInfo> FMV = getFMVInfoFrom(Feature)) {
+      // FMV feature without a corresponding Arch Extension may affect priority
+      if (FMV->ID)
+        FeatureBits.enable(*FMV->ID);
+      else
+        PriorityMask |= (1ULL << FMV->PriorityBit);
     }
-    if (FMV && FMV->ID)
-      FeatureBits.enable(*FMV->ID);
   }
 
   // Construct a bitmask for all the transitively enabled Arch Extensions.
-  uint64_t PriorityMask = 0;
   for (const FMVInfo &Info : getFMVInfo())
     if (Info.ID && FeatureBits.Enabled.test(*Info.ID))
       PriorityMask |= (1ULL << Info.PriorityBit);
@@ -81,9 +90,9 @@ uint64_t AArch64::getCpuSupportsMask(ArrayRef<StringRef> Features) {
   // Transitively enable the Arch Extensions which correspond to each feature.
   ExtensionSet FeatureBits;
   for (const StringRef Feature : Features)
-    if (std::optional<FMVInfo> Info = parseFMVExtension(Feature))
-      if (Info->ID)
-        FeatureBits.enable(*Info->ID);
+    if (std::optional<FMVInfo> FMV = getFMVInfoFrom(Feature))
+      if (FMV->ID)
+        FeatureBits.enable(*FMV->ID);
 
   // Construct a bitmask for all the transitively enabled Arch Extensions.
   uint64_t FeaturesMask = 0;