https://github.com/hanickadot created
https://github.com/llvm/llvm-project/pull/98756
This implements clang support for P3309 constexpr std::atomic & std::atomic_ref
(currently in LWG) by allowing constant evaluation of clang's __c11_atomic_OP
and GCC's __atomic_OP builtins.
From e42b4a8877fed0096e44961235a61192ecb8e620 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Hana=20Dusi=CC=81kova=CC=81?= <hani...@hanicka.net>
Date: Sat, 13 Jul 2024 20:10:26 +0200
Subject: [PATCH] [clang] constexpr atomic builtins (__c11_atomic_OP and
__atomic_OP)
---
clang/include/clang/Basic/Builtins.td | 84 +--
clang/lib/AST/ExprConstant.cpp | 553 +++++++++++++++++-
.../SemaCXX/atomic-constexpr-c11-builtins.cpp | 288 +++++++++
.../SemaCXX/atomic-constexpr-gcc-builtins.cpp | 494 ++++++++++++++++
4 files changed, 1371 insertions(+), 48 deletions(-)
create mode 100644 clang/test/SemaCXX/atomic-constexpr-c11-builtins.cpp
create mode 100644 clang/test/SemaCXX/atomic-constexpr-gcc-builtins.cpp
diff --git a/clang/include/clang/Basic/Builtins.td
b/clang/include/clang/Basic/Builtins.td
index f5b15cf90d1f8..0716cf02f5110 100644
--- a/clang/include/clang/Basic/Builtins.td
+++ b/clang/include/clang/Basic/Builtins.td
@@ -1682,97 +1682,97 @@ def SyncSwapN : Builtin, SyncBuiltinsTemplate {
// C11 _Atomic operations for <stdatomic.h>.
def C11AtomicInit : AtomicBuiltin {
let Spellings = ["__c11_atomic_init"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicLoad : AtomicBuiltin {
let Spellings = ["__c11_atomic_load"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicStore : AtomicBuiltin {
let Spellings = ["__c11_atomic_store"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicExchange : AtomicBuiltin {
let Spellings = ["__c11_atomic_exchange"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicCompareExchangeStrong : AtomicBuiltin {
let Spellings = ["__c11_atomic_compare_exchange_strong"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicCompareExchangeWeak : AtomicBuiltin {
let Spellings = ["__c11_atomic_compare_exchange_weak"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicFetchAdd : AtomicBuiltin {
let Spellings = ["__c11_atomic_fetch_add"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicFetchSub : AtomicBuiltin {
let Spellings = ["__c11_atomic_fetch_sub"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicFetchAnd : AtomicBuiltin {
let Spellings = ["__c11_atomic_fetch_and"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicFetchOr : AtomicBuiltin {
let Spellings = ["__c11_atomic_fetch_or"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicFetchXor : AtomicBuiltin {
let Spellings = ["__c11_atomic_fetch_xor"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicFetchNand : AtomicBuiltin {
let Spellings = ["__c11_atomic_fetch_nand"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicFetchMax : AtomicBuiltin {
let Spellings = ["__c11_atomic_fetch_max"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicFetchMin : AtomicBuiltin {
let Spellings = ["__c11_atomic_fetch_min"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def C11AtomicThreadFence : Builtin {
let Spellings = ["__c11_atomic_thread_fence"];
- let Attributes = [NoThrow];
+ let Attributes = [NoThrow, Constexpr];
let Prototype = "void(int)";
}
def C11AtomicSignalFence : Builtin {
let Spellings = ["__c11_atomic_signal_fence"];
- let Attributes = [NoThrow];
+ let Attributes = [NoThrow, Constexpr];
let Prototype = "void(int)";
}
@@ -1785,157 +1785,157 @@ def C11AtomicIsLockFree : Builtin {
// GNU atomic builtins.
def AtomicLoad : AtomicBuiltin {
let Spellings = ["__atomic_load"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicLoadN : AtomicBuiltin {
let Spellings = ["__atomic_load_n"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicStore : AtomicBuiltin {
let Spellings = ["__atomic_store"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicStoreN : AtomicBuiltin {
let Spellings = ["__atomic_store_n"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicExchange : AtomicBuiltin {
let Spellings = ["__atomic_exchange"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicExchangeN : AtomicBuiltin {
let Spellings = ["__atomic_exchange_n"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicCompareExchange : AtomicBuiltin {
let Spellings = ["__atomic_compare_exchange"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicCompareExchangeN : AtomicBuiltin {
let Spellings = ["__atomic_compare_exchange_n"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicFetchAdd : AtomicBuiltin {
let Spellings = ["__atomic_fetch_add"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicFetchSub : AtomicBuiltin {
let Spellings = ["__atomic_fetch_sub"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicFetchAnd : AtomicBuiltin {
let Spellings = ["__atomic_fetch_and"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicFetchOr : AtomicBuiltin {
let Spellings = ["__atomic_fetch_or"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicFetchXor : AtomicBuiltin {
let Spellings = ["__atomic_fetch_xor"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicFetchNand : AtomicBuiltin {
let Spellings = ["__atomic_fetch_nand"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicAddFetch : AtomicBuiltin {
let Spellings = ["__atomic_add_fetch"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicSubFetch : AtomicBuiltin {
let Spellings = ["__atomic_sub_fetch"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicAndFetch : AtomicBuiltin {
let Spellings = ["__atomic_and_fetch"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicOrFetch : AtomicBuiltin {
let Spellings = ["__atomic_or_fetch"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicXorFetch : AtomicBuiltin {
let Spellings = ["__atomic_xor_fetch"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicMaxFetch : AtomicBuiltin {
let Spellings = ["__atomic_max_fetch"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicMinFetch : AtomicBuiltin {
let Spellings = ["__atomic_min_fetch"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicNandFetch : AtomicBuiltin {
let Spellings = ["__atomic_nand_fetch"];
- let Attributes = [CustomTypeChecking];
+ let Attributes = [CustomTypeChecking, Constexpr];
let Prototype = "void(...)";
}
def AtomicTestAndSet : Builtin {
let Spellings = ["__atomic_test_and_set"];
- let Attributes = [NoThrow];
+ let Attributes = [NoThrow, Constexpr];
let Prototype = "bool(void volatile*, int)";
}
def AtomicClear : Builtin {
let Spellings = ["__atomic_clear"];
- let Attributes = [NoThrow];
+ let Attributes = [NoThrow, Constexpr];
let Prototype = "void(void volatile*, int)";
}
def AtomicThreadFence : Builtin {
let Spellings = ["__atomic_thread_fence"];
- let Attributes = [NoThrow];
+ let Attributes = [NoThrow, Constexpr];
let Prototype = "void(int)";
}
def AtomicSignalFence : Builtin {
let Spellings = ["__atomic_signal_fence"];
- let Attributes = [NoThrow];
+ let Attributes = [NoThrow, Constexpr];
let Prototype = "void(int)";
}
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 0aeac9d03eed3..c472b4b998aa3 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -1900,6 +1900,17 @@ static bool EvaluateFixedPoint(const Expr *E,
APFixedPoint &Result,
// Misc utilities
//===----------------------------------------------------------------------===//
+static bool isOnePastTheEndOfCompleteObject(const ASTContext &Ctx,
+ const LValue &LV);
+
+enum class SizeOfType {
+ SizeOf,
+ DataSizeOf,
+};
+
+static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc, QualType Type,
+ CharUnits &Size, SizeOfType SOT = SizeOfType::SizeOf);
+
/// Negate an APSInt in place, converting it to a signed form if necessary, and
/// preserving its value (by extending by up to one bit as needed).
static void negateAsSigned(APSInt &Int) {
@@ -3222,14 +3233,9 @@ static bool HandleLValueIndirectMember(EvalInfo &Info,
const Expr *E,
return true;
}
-enum class SizeOfType {
- SizeOf,
- DataSizeOf,
-};
-
/// Get the size of the given type in char units.
static bool HandleSizeof(EvalInfo &Info, SourceLocation Loc, QualType Type,
- CharUnits &Size, SizeOfType SOT = SizeOfType::SizeOf)
{
+ CharUnits &Size, SizeOfType SOT) {
// sizeof(void), __alignof__(void), sizeof(function) = 1 as a gcc
// extension.
if (Type->isVoidType() || Type->isFunctionType()) {
@@ -7884,6 +7890,522 @@ class ExprEvaluatorBase
return StmtVisitorTy::Visit(Source);
}
+ static bool EvaluateAtomicOrderToIgnore(const AtomicExpr *E, EvalInfo &Info)
{
+ // we ignore results, but we need to evaluate them
+ [[maybe_unused]] APSInt OrderIgnoredResult;
+
+ const Expr *OrderSuccess = E->getOrder();
+ if (!EvaluateInteger(OrderSuccess, OrderIgnoredResult, Info))
+ return false;
+
+ if (E->isCmpXChg()) {
+ const Expr *OrderFail = E->getOrderFail();
+ if (!EvaluateInteger(OrderFail, OrderIgnoredResult, Info))
+ return false;
+ }
+
+ return true;
+ }
+
+ static bool EvaluateAtomicWeakToIgnore(const AtomicExpr *E, EvalInfo &Info) {
+ // we ignore results, but we need to evaluate them
+ [[maybe_unused]] APSInt WeakIgnoredResult;
+
+ if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange_n ||
+ E->getOp() == AtomicExpr::AO__atomic_compare_exchange) {
+ const Expr *Weak = E->getWeak();
+ if (!EvaluateInteger(Weak, WeakIgnoredResult, Info))
+ return false;
+ }
+
+ return true;
+ }
+
+ static bool LoadAtomicValue(const AtomicExpr *E, APValue &Result,
+ EvalInfo &Info) {
+ LValue AtomicStorageLV;
+
+ if (!EvaluatePointer(E->getPtr(), AtomicStorageLV, Info))
+ return false;
+
+ return handleLValueToRValueConversion(Info, E->getPtr(), E->getValueType(),
+ AtomicStorageLV, Result);
+ }
+
+ static bool StoreValueIntoResultPointer(Expr *ResultPtr,
+ APValue &ValueToStore,
+ EvalInfo &Info) {
+ // TODO check it must be a pointer
+ assert(ResultPtr->getType()->isPointerType());
+ QualType PointeeTy = ResultPtr->getType()->getPointeeType();
+ LValue PointeeLV;
+
+ if (!EvaluatePointer(ResultPtr, PointeeLV, Info))
+ return false;
+
+ return handleAssignment(Info, ResultPtr, PointeeLV, PointeeTy,
+ ValueToStore);
+ }
+
+ static bool LoadAtomicValueInto(const AtomicExpr *E, EvalInfo &Info) {
+ APValue LocalResult;
+
+ if (!LoadAtomicValue(E, LocalResult, Info))
+ return false;
+
+ if (!StoreValueIntoResultPointer(E->getVal1(), LocalResult, Info))
+ return false;
+
+ return true;
+ }
+
+ static bool StoreAtomicValue(const AtomicExpr *E, EvalInfo &Info) {
+ LValue AtomicStorageLV;
+
+ if (!EvaluatePointer(E->getPtr(), AtomicStorageLV, Info))
+ return false;
+
+ APValue ProvidedValue;
+
+ // GCC's atomic_store takes pointer to value, not value itself
+ if (E->getOp() == AtomicExpr::AO__atomic_store) {
+ LValue ProvidedLV;
+ if (!EvaluatePointer(E->getVal1(), ProvidedLV, Info))
+ return false;
+
+ if (!handleLValueToRValueConversion(Info, E->getVal1(),
+ E->getVal1()->getType(), ProvidedLV,
+ ProvidedValue))
+ return false;
+
+ } else {
+ if (!Evaluate(ProvidedValue, Info, E->getVal1()))
+ return false;
+ }
+ if (!handleAssignment(Info, E, AtomicStorageLV, E->getValueType(),
+ ProvidedValue))
+ return false;
+
+ return true;
+ }
+
+ static bool ExchangeAtomicValueInto(const AtomicExpr *E, EvalInfo &Info) {
+ assert(E->getOp() == AtomicExpr::AO__atomic_exchange);
+ // implementation of GCC's exchange (non _n version)
+ LValue AtomicStorageLV;
+ if (!EvaluatePointer(E->getPtr(), AtomicStorageLV, Info))
+ return false;
+
+ // read previous value
+ APValue PreviousValue;
+ if (!handleLValueToRValueConversion(Info, E->getPtr(), E->getValueType(),
+ AtomicStorageLV, PreviousValue))
+ return false;
+
+ // get provided value from argument (pointer)
+ LValue ProvidedLV;
+ if (!EvaluatePointer(E->getVal1(), ProvidedLV, Info))
+ return false;
+
+ APValue ProvidedValue;
+ if (!handleLValueToRValueConversion(Info, E->getVal1(),
+ E->getVal1()->getType(), ProvidedLV,
+ ProvidedValue))
+ return false;
+
+ // store provided value to atomic value
+ if (!handleAssignment(Info, E, AtomicStorageLV, E->getValueType(),
+ ProvidedValue))
+ return false;
+
+ // store previous value in output pointer
+ if (!StoreValueIntoResultPointer(E->getVal2(), PreviousValue, Info))
+ return false;
+
+ return true;
+ }
+
+ static bool FetchAtomicOp(const AtomicExpr *E, APValue &Result,
+ EvalInfo &Info, bool StoreToResultAfter) {
+ // read atomic
+ LValue AtomicStorageLV;
+ QualType AtomicValueTy = E->getValueType();
+ if (!EvaluatePointer(E->getPtr(), AtomicStorageLV, Info))
+ return false;
+
+ APValue CurrentValue;
+ if (!handleLValueToRValueConversion(Info, E->getPtr(), E->getType(),
+ AtomicStorageLV, CurrentValue))
+ return false;
+
+ // store current value for fetch-OP operations
+ if (!StoreToResultAfter)
+ Result = CurrentValue;
+
+ // read argument for fetch OP
+ APValue ArgumentVal;
+ if (!Evaluate(ArgumentVal, Info, E->getVal1()))
+ return false;
+
+ // calculate new value
+ APValue Replacement;
+ if (AtomicValueTy->isIntegralOrEnumerationType()) {
+ // both arguments are integers
+ const APSInt AtomicInt = CurrentValue.getInt();
+ const APSInt ArgumentInt = ArgumentVal.getInt();
+
+ switch (E->getOp()) {
+ case AtomicExpr::AO__c11_atomic_fetch_add:
+ case AtomicExpr::AO__atomic_fetch_add:
+ case AtomicExpr::AO__atomic_add_fetch:
+ Replacement = APValue(AtomicInt + ArgumentInt);
+ break;
+ case AtomicExpr::AO__c11_atomic_fetch_sub:
+ case AtomicExpr::AO__atomic_fetch_sub:
+ case AtomicExpr::AO__atomic_sub_fetch:
+ Replacement = APValue(AtomicInt - ArgumentInt);
+ break;
+ case AtomicExpr::AO__c11_atomic_fetch_and:
+ case AtomicExpr::AO__atomic_fetch_and:
+ case AtomicExpr::AO__atomic_and_fetch:
+ Replacement = APValue(AtomicInt & ArgumentInt);
+ break;
+ case AtomicExpr::AO__c11_atomic_fetch_or:
+ case AtomicExpr::AO__atomic_fetch_or:
+ case AtomicExpr::AO__atomic_or_fetch:
+ Replacement = APValue(AtomicInt | ArgumentInt);
+ break;
+ case AtomicExpr::AO__c11_atomic_fetch_xor:
+ case AtomicExpr::AO__atomic_fetch_xor:
+ case AtomicExpr::AO__atomic_xor_fetch:
+ Replacement = APValue(AtomicInt ^ ArgumentInt);
+ break;
+ case AtomicExpr::AO__c11_atomic_fetch_nand:
+ case AtomicExpr::AO__atomic_fetch_nand:
+ case AtomicExpr::AO__atomic_nand_fetch:
+ Replacement = APValue(~(AtomicInt & ArgumentInt));
+ break;
+ case AtomicExpr::AO__c11_atomic_fetch_max:
+ case AtomicExpr::AO__atomic_fetch_max:
+ case AtomicExpr::AO__atomic_max_fetch:
+ Replacement =
+ APValue((AtomicInt > ArgumentInt) ? AtomicInt : ArgumentInt);
+ break;
+ case AtomicExpr::AO__c11_atomic_fetch_min:
+ case AtomicExpr::AO__atomic_fetch_min:
+ case AtomicExpr::AO__atomic_min_fetch:
+ Replacement =
+ APValue((AtomicInt < ArgumentInt) ? AtomicInt : ArgumentInt);
+ break;
+ default:
+ return false;
+ }
+ } else if (AtomicValueTy->isRealFloatingType()) {
+ // both arguments are float operations
+ const llvm::RoundingMode RM = getActiveRoundingMode(Info, E);
+ APFloat AtomicFlt = CurrentValue.getFloat();
+ const APFloat ArgumentFlt = ArgumentVal.getFloat();
+ APFloat::opStatus St;
+
+ switch (E->getOp()) {
+ case AtomicExpr::AO__c11_atomic_fetch_add: // GCC atomics doesn't support
+ // floats
+ St = AtomicFlt.add(ArgumentFlt, RM);
+ Replacement = APValue(AtomicFlt);
+ break;
+ case AtomicExpr::AO__c11_atomic_fetch_sub:
+ St = AtomicFlt.subtract(ArgumentFlt, RM);
+ Replacement = APValue(AtomicFlt);
+ break;
+ default:
+ return false;
+ }
+
+ if (!checkFloatingPointResult(Info, E, St))
+ return false;
+
+ } else if (AtomicValueTy->isPointerType()) {
+ // pointer + int arguments
+ LValue AtomicPtr;
+ AtomicPtr.setFrom(Info.Ctx, CurrentValue);
+
+ APSInt ArgumentInt = ArgumentVal.getInt();
+
+ // calculate size of pointee object
+ CharUnits SizeOfPointee;
+ if (!HandleSizeof(Info, E->getExprLoc(), AtomicValueTy->getPointeeType(),
+ SizeOfPointee))
+ return false;
+
+ // GCC's atomic_fetch add/sub compute new pointer by bytes and not
+ // sizeof(T)
+ switch (E->getOp()) {
+ case AtomicExpr::AO__atomic_fetch_add:
+ case AtomicExpr::AO__atomic_add_fetch:
+ case AtomicExpr::AO__atomic_fetch_sub:
+ case AtomicExpr::AO__atomic_sub_fetch: {
+ const auto sizeOfOneItem =
+ APSInt(APInt(ArgumentInt.getBitWidth(),
SizeOfPointee.getQuantity(),
+ false),
+ false);
+ // incrementing pointer by size which is not dividable by pointee size
+ // is UB and therefore disallowed
+ if ((ArgumentInt % sizeOfOneItem) != 0)
+ return false;
+
+ ArgumentInt /= sizeOfOneItem;
+ } break;
+ default:
+ break;
+ }
+
+ switch (E->getOp()) {
+ case AtomicExpr::AO__c11_atomic_fetch_add:
+ case AtomicExpr::AO__atomic_fetch_add:
+ case AtomicExpr::AO__atomic_add_fetch:
+ AtomicPtr.adjustOffsetAndIndex(Info, E, ArgumentInt, SizeOfPointee);
+ break;
+ case AtomicExpr::AO__c11_atomic_fetch_sub:
+ case AtomicExpr::AO__atomic_fetch_sub:
+ case AtomicExpr::AO__atomic_sub_fetch:
+ ArgumentInt.negate();
+ AtomicPtr.adjustOffsetAndIndex(Info, E, ArgumentInt, SizeOfPointee);
+ break;
+ default:
+ return false;
+ }
+
+ AtomicPtr.moveInto(Replacement);
+ } else {
+ // not float,int,pointer?
+ return false;
+ }
+
+ // OP-fetch operation store result, not previous value
+ if (StoreToResultAfter)
+ Result = Replacement;
+
+ // store result to atomic's storage
+ return handleAssignment(Info, E, AtomicStorageLV, AtomicValueTy,
+ Replacement);
+ }
+
+ static bool CompareExchangeAtomicValue(const AtomicExpr *E, APValue &Result,
+ EvalInfo &Info) {
+ EvaluateAtomicWeakToIgnore(E, Info);
+
+ // dereference _Atomic * (atomic value)
+ LValue AtomicLV;
+ QualType AtomicTy = E->getValueType();
+ if (!EvaluatePointer(E->getPtr(), AtomicLV, Info)) {
+ return false;
+ }
+
+ // dereference T * (expected value)
+ LValue ExpectedLV;
+ QualType ExpectedTy = E->getVal1()->getType()->getPointeeType();
+ if (!EvaluatePointer(E->getVal1(), ExpectedLV, Info)) {
+ return false;
+ }
+
+ // get values for atomic and expected
+ APValue AtomicVal;
+ APValue ExpectedVal;
+
+ // convert pointer to value
+ if (!handleLValueToRValueConversion(Info, E->getPtr(), AtomicTy, AtomicLV,
+ AtomicVal)) {
+ return false;
+ }
+
+ if (!handleLValueToRValueConversion(Info, E->getVal1(), ExpectedTy,
+ ExpectedLV, ExpectedVal)) {
+ return false;
+ }
+
+ bool DoExchange = false;
+
+ // compare atomic<int> and friends
+ if (AtomicTy->isIntegralOrEnumerationType() &&
+ ExpectedTy->isIntegralOrEnumerationType()) {
+ const APSInt AtomicInt = AtomicVal.getInt();
+ const APSInt ExpectedInt = ExpectedVal.getInt();
+ if (AtomicInt == ExpectedInt) {
+ DoExchange = true;
+ }
+ } else if (AtomicTy->isRealFloatingType() &&
+ ExpectedTy->isRealFloatingType()) {
+ const APFloat AtomicFlt = AtomicVal.getFloat();
+ const APFloat ExpectedFlt = ExpectedVal.getFloat();
+ if (AtomicFlt == ExpectedFlt) {
+ DoExchange = true;
+ }
+ } else if (AtomicTy->isPointerType() && ExpectedTy->isPointerType()) {
+ // get LValue of objects pointed to
+ LValue LHS;
+ LHS.setFrom(Info.Ctx, AtomicVal);
+
+ LValue RHS;
+ RHS.setFrom(Info.Ctx, ExpectedVal);
+
+ if (HasSameBase(LHS, RHS)) {
+ const CharUnits &LHSOffset = LHS.getLValueOffset();
+ const CharUnits &RHSOffset = RHS.getLValueOffset();
+
+ const unsigned PtrSize = Info.Ctx.getTypeSize(AtomicTy);
+ assert(PtrSize <= 64 && "Pointer width is larger than expected");
+ const uint64_t Mask = ~0ULL >> (64 - PtrSize);
+
+ const uint64_t CompareLHS = LHSOffset.getQuantity() & Mask;
+ const uint64_t CompareRHS = RHSOffset.getQuantity() & Mask;
+
+ if (CompareLHS == CompareRHS) {
+ DoExchange = true;
+ }
+ } else {
+
+ // it's implementation-defined to compare distinct literals
+ // it's not constant-evaluation
+ if ((IsLiteralLValue(LHS) || IsLiteralLValue(RHS)) && LHS.Base &&
+ RHS.Base) {
+ return false;
+ }
+
+ if (IsWeakLValue(LHS) || IsWeakLValue(RHS)) {
+ return false;
+ }
+
+ if ((!LHS.Base && !LHS.Offset.isZero()) ||
+ (!RHS.Base && !RHS.Offset.isZero())) {
+ return false;
+ }
+
+ if (LHS.Base && LHS.Offset.isZero() &&
+ isOnePastTheEndOfCompleteObject(Info.Ctx, RHS)) {
+ return false;
+ }
+
+ if (RHS.Base && RHS.Offset.isZero() &&
+ isOnePastTheEndOfCompleteObject(Info.Ctx, LHS)) {
+ return false;
+ }
+
+ if ((RHS.Base && isZeroSized(RHS)) || (LHS.Base && isZeroSized(LHS))) {
+ return false;
+ }
+
+ // after all it's a different object
+ DoExchange = false;
+ }
+
+ } else {
+ return false;
+ }
+
+ APValue Replacement;
+ if (E->getOp() == AtomicExpr::AO__atomic_compare_exchange) {
+ // GCC atomic_compare_exchange provides pointer and not value
+ LValue ReplacementLV;
+ if (!EvaluatePointer(E->getVal2(), ReplacementLV, Info))
+ return false;
+
+ if (!handleLValueToRValueConversion(Info, E->getVal2(),
+ E->getVal2()->getType(),
+ ReplacementLV, Replacement))
+ return false;
+
+ } else {
+ if (!Evaluate(Replacement, Info, E->getVal2())) {
+ return false;
+ }
+ }
+
+ if (DoExchange) {
+ // if values are same do the exchange with replacement value
+ // but first I must evaluate the replacement value
+
+ // and assign it to atomic
+ if (!handleAssignment(Info, E, AtomicLV, AtomicTy, Replacement)) {
+ return false;
+ }
+ }
+
+ // to expected pointer I need to put previous value in atomic
+ if (!handleAssignment(Info, E, ExpectedLV, ExpectedTy, AtomicVal)) {
+ return false;
+ }
+
+ // and return boolean if I did the exchange
+ Result = APValue(Info.Ctx.MakeIntValue(DoExchange, E->getType()));
+ return true;
+ }
+
+ bool VisitAtomicExpr(const AtomicExpr *E) {
+ if (!EvaluateAtomicOrderToIgnore(E, Info))
+ return false;
+
+ APValue LocalResult;
+ switch (E->getOp()) {
+ default:
+ return Error(E);
+ case AtomicExpr::AO__c11_atomic_load:
+ case AtomicExpr::AO__atomic_load_n:
+ if (!LoadAtomicValue(E, LocalResult, Info)) {
+ return Error(E);
+ }
+ return DerivedSuccess(LocalResult, E);
+ case AtomicExpr::AO__c11_atomic_compare_exchange_strong:
+ case AtomicExpr::AO__c11_atomic_compare_exchange_weak:
+ case AtomicExpr::AO__atomic_compare_exchange:
+ case AtomicExpr::AO__atomic_compare_exchange_n:
+ if (!CompareExchangeAtomicValue(E, LocalResult, Info)) {
+ return Error(E);
+ }
+ return DerivedSuccess(LocalResult, E);
+ case AtomicExpr::AO__c11_atomic_exchange:
+ case AtomicExpr::AO__atomic_exchange_n:
+ if (!LoadAtomicValue(E, LocalResult, Info)) {
+ return Error(E);
+ }
+ if (!StoreAtomicValue(E, Info)) {
+ return Error(E);
+ }
+ return DerivedSuccess(LocalResult, E);
+ case AtomicExpr::AO__c11_atomic_fetch_add:
+ case AtomicExpr::AO__c11_atomic_fetch_sub:
+ case AtomicExpr::AO__c11_atomic_fetch_and:
+ case AtomicExpr::AO__c11_atomic_fetch_or:
+ case AtomicExpr::AO__c11_atomic_fetch_xor:
+ case AtomicExpr::AO__c11_atomic_fetch_nand:
+ case AtomicExpr::AO__c11_atomic_fetch_max:
+ case AtomicExpr::AO__c11_atomic_fetch_min:
+ case AtomicExpr::AO__atomic_fetch_add:
+ case AtomicExpr::AO__atomic_fetch_sub:
+ case AtomicExpr::AO__atomic_fetch_and:
+ case AtomicExpr::AO__atomic_fetch_xor:
+ case AtomicExpr::AO__atomic_fetch_or:
+ case AtomicExpr::AO__atomic_fetch_nand:
+ case AtomicExpr::AO__atomic_fetch_max:
+ case AtomicExpr::AO__atomic_fetch_min:
+ if (!FetchAtomicOp(E, LocalResult, Info, false)) {
+ return Error(E);
+ }
+ return DerivedSuccess(LocalResult, E);
+ case AtomicExpr::AO__atomic_add_fetch:
+ case AtomicExpr::AO__atomic_sub_fetch:
+ case AtomicExpr::AO__atomic_and_fetch:
+ case AtomicExpr::AO__atomic_xor_fetch:
+ case AtomicExpr::AO__atomic_or_fetch:
+ case AtomicExpr::AO__atomic_nand_fetch:
+ case AtomicExpr::AO__atomic_max_fetch:
+ case AtomicExpr::AO__atomic_min_fetch:
+ if (!FetchAtomicOp(E, LocalResult, Info, true)) {
+ return Error(E);
+ }
+ return DerivedSuccess(LocalResult, E);
+ }
+ }
+
bool VisitPseudoObjectExpr(const PseudoObjectExpr *E) {
for (const Expr *SemE : E->semantics()) {
if (auto *OVE = dyn_cast<OpaqueValueExpr>(SemE)) {
@@ -15595,6 +16117,25 @@ class VoidExprEvaluator
}
}
+ bool VisitAtomicExpr(const AtomicExpr *E) {
+ if (!EvaluateAtomicOrderToIgnore(E, Info))
+ return false;
+
+ switch (E->getOp()) {
+ default:
+ return Error(E);
+ case AtomicExpr::AO__atomic_load:
+ return LoadAtomicValueInto(E, Info);
+ case AtomicExpr::AO__atomic_exchange:
+ return ExchangeAtomicValueInto(E, Info);
+ case AtomicExpr::AO__c11_atomic_init:
+ case AtomicExpr::AO__c11_atomic_store:
+ case AtomicExpr::AO__atomic_store:
+ case AtomicExpr::AO__atomic_store_n:
+ return StoreAtomicValue(E, Info);
+ }
+ }
+
bool VisitCallExpr(const CallExpr *E) {
if (!IsConstantEvaluatedBuiltinCall(E))
return ExprEvaluatorBaseTy::VisitCallExpr(E);
diff --git a/clang/test/SemaCXX/atomic-constexpr-c11-builtins.cpp
b/clang/test/SemaCXX/atomic-constexpr-c11-builtins.cpp
new file mode 100644
index 0000000000000..3dc18b3d7c730
--- /dev/null
+++ b/clang/test/SemaCXX/atomic-constexpr-c11-builtins.cpp
@@ -0,0 +1,288 @@
+// RUN: %clang_cc1 -std=c++20 %s
+
+// expected-no-diagnostics
+
+constexpr int int_min = -2147483648;
+constexpr int int_max = 2147483647;
+
+const int array[2] = {1,2};
+const char small_array[2] = {1,2};
+
+template <typename T> struct identity {
+ using type = T;
+};
+
+template <typename T> using do_not_deduce = typename identity<T>::type;
+
+// -- LOAD --
+
+template <typename T> consteval T load(T value) {
+ _Atomic(T) av = value;
+ return __c11_atomic_load(&av, __ATOMIC_RELAXED);
+}
+
+// integers
+static_assert(load(true) == true);
+static_assert(load(false) == false);
+
+static_assert(load(42) == 42);
+static_assert(load(-128) == -128);
+
+static_assert(load(42u) == 42u);
+static_assert(load(0xFFFFFFFFu) == 0xFFFFFFFFu);
+
+// floats
+static_assert(load(42.3) == 42.3);
+static_assert(load(42.3f) == 42.3f);
+
+// pointers
+static_assert(load(&array[0]) == &array[0]);
+static_assert(load(&small_array[1]) == &small_array[1]);
+
+// -- STORE --
+
+template <typename T> consteval T store(T value) {
+ _Atomic(T) av = T{};
+ __c11_atomic_store(&av, value, __ATOMIC_RELAXED);
+ return __c11_atomic_load(&av, __ATOMIC_RELAXED);
+}
+
+// integers
+static_assert(store(true) == true);
+static_assert(store(false) == false);
+
+static_assert(store(42) == 42);
+static_assert(store(-128) == -128);
+
+static_assert(store(42u) == 42u);
+static_assert(store(0xFFFFFFFFu) == 0xFFFFFFFFu);
+
+// floats
+static_assert(store(42.3) == 42.3);
+static_assert(store(42.3f) == 42.3f);
+
+// pointers
+static_assert(store(&array[0]) == &array[0]);
+static_assert(store(&small_array[1]) == &small_array[1]);
+
+// -- EXCHANGE --
+template <typename T> struct two_values {
+ T before;
+ T after;
+ constexpr friend bool operator==(two_values, two_values) = default;
+};
+
+template <typename T> consteval auto exchange(T value, do_not_deduce<T>
replacement) -> two_values<T> {
+ _Atomic(T) av = T{value};
+ T previous = __c11_atomic_exchange(&av, replacement, __ATOMIC_RELAXED);
+ return two_values<T>{previous, __c11_atomic_load(&av, __ATOMIC_RELAXED)};
+}
+
+// integers
+static_assert(exchange(true,false) == two_values{true, false});
+static_assert(exchange(false,true) == two_values{false, true});
+
+static_assert(exchange(10,42) == two_values{10,42});
+static_assert(exchange(14,-128) == two_values{14,-128});
+
+
+static_assert(exchange(56u,42u) == two_values{56u,42u});
+static_assert(exchange(0xFFu, 0xFFFFFFFFu) == two_values{0xFFu,0xFFFFFFFFu});
+
+// floats
+static_assert(exchange(42.3,1.2) == two_values{42.3,1.2});
+static_assert(exchange(42.3f,-16.7f) == two_values{42.3f, -16.7f});
+
+// pointers
+static_assert(exchange(&array[0], &array[1]) ==
two_values{&array[0],&array[1]});
+static_assert(exchange(&small_array[1], &small_array[0]) ==
two_values{&small_array[1], &small_array[0]});
+
+// -- COMPARE-EXCHANGE --
+template <typename T> struct comp_result {
+ bool success;
+ T output;
+ T after;
+
+ constexpr comp_result(bool success_, T output_, do_not_deduce<T> after_):
success{success_}, output{output_}, after{after_} { }
+
+ constexpr friend bool operator==(comp_result, comp_result) = default;
+};
+
+template <typename T> constexpr auto comp_success(T output, do_not_deduce<T>
after) {
+ return comp_result<T>{true, output, after};
+}
+
+template <typename T> constexpr auto comp_failure(T after) {
+ return comp_result<T>{false, after, after};
+}
+
+template <typename T> consteval auto compare_exchange_weak(T original,
do_not_deduce<T> expected, do_not_deduce<T> replacement) -> comp_result<T> {
+ _Atomic(T) av = T{original};
+ const bool success = __c11_atomic_compare_exchange_weak(&av, &expected,
replacement, __ATOMIC_RELAXED, __ATOMIC_RELAXED);
+ return comp_result<T>{success, expected, __c11_atomic_load(&av,
__ATOMIC_RELAXED)};
+}
+
+// integers
+static_assert(compare_exchange_weak(true, true, false) == comp_success(true,
false));
+static_assert(compare_exchange_weak(false, false, true) == comp_success(false,
true));
+static_assert(compare_exchange_weak(false, true, false) ==
comp_failure(false));
+static_assert(compare_exchange_weak(true, false, true) == comp_failure(true));
+
+static_assert(compare_exchange_weak(10,10,42) == comp_success(10,42));
+static_assert(compare_exchange_weak(14,14,-128) == comp_success(14,-128));
+static_assert(compare_exchange_weak(-10,10,42) == comp_failure(-10));
+static_assert(compare_exchange_weak(-14,14,-128) == comp_failure(-14));
+
+static_assert(compare_exchange_weak(56u, 56u,42u) == comp_success(56u,42u));
+static_assert(compare_exchange_weak(0xFFu, 0xFFu, 0xFFFFFFFFu) ==
comp_success(0xFFu,0xFFFFFFFFu));
+static_assert(compare_exchange_weak(3u, 56u,42u) == comp_failure(3u));
+static_assert(compare_exchange_weak(0xFu, 0xFFu, 0xFFFFFFFFu) ==
comp_failure(0xFu));
+
+// floats
+static_assert(compare_exchange_weak(42.3, 42.3,1.2) == comp_success(42.3,1.2));
+static_assert(compare_exchange_weak(42.3f, 42.3f,-16.7f) ==
comp_success(42.3f, -16.7f));
+static_assert(compare_exchange_weak(0.0, 42.3,1.2) == comp_failure(0.0));
+static_assert(compare_exchange_weak(0.0f, 42.3f,-16.7f) == comp_failure(0.0f));
+
+// pointers
+static_assert(compare_exchange_weak(&array[0], &array[0], &array[1]) ==
comp_success(&array[0],&array[1]));
+static_assert(compare_exchange_weak(&small_array[1], &small_array[1],
&small_array[0]) == comp_success(&small_array[1], &small_array[0]));
+static_assert(compare_exchange_weak(&array[1], &array[0], &array[1]) ==
comp_failure(&array[1]));
+static_assert(compare_exchange_weak(&small_array[0], &small_array[1],
&small_array[0]) == comp_failure(&small_array[0]));
+
+
+template <typename T> consteval auto compare_exchange_strong(T original,
do_not_deduce<T> expected, do_not_deduce<T> replacement) -> comp_result<T> {
+ _Atomic(T) av = T{original};
+ const bool success = __c11_atomic_compare_exchange_strong(&av, &expected,
replacement, __ATOMIC_RELAXED, __ATOMIC_RELAXED);
+ return comp_result<T>{success, expected, __c11_atomic_load(&av,
__ATOMIC_RELAXED)};
+}
+
+// integers
+static_assert(compare_exchange_strong(true, true, false) == comp_success(true,
false));
+static_assert(compare_exchange_strong(false, false, true) ==
comp_success(false, true));
+static_assert(compare_exchange_strong(false, true, false) ==
comp_failure(false));
+static_assert(compare_exchange_strong(true, false, true) ==
comp_failure(true));
+
+static_assert(compare_exchange_strong(10,10,42) == comp_success(10,42));
+static_assert(compare_exchange_strong(14,14,-128) == comp_success(14,-128));
+static_assert(compare_exchange_strong(-10,10,42) == comp_failure(-10));
+static_assert(compare_exchange_strong(-14,14,-128) == comp_failure(-14));
+
+static_assert(compare_exchange_strong(56u, 56u,42u) == comp_success(56u,42u));
+static_assert(compare_exchange_strong(0xFFu, 0xFFu, 0xFFFFFFFFu) ==
comp_success(0xFFu,0xFFFFFFFFu));
+static_assert(compare_exchange_strong(3u, 56u,42u) == comp_failure(3u));
+static_assert(compare_exchange_strong(0xFu, 0xFFu, 0xFFFFFFFFu) ==
comp_failure(0xFu));
+
+// floats
+static_assert(compare_exchange_strong(42.3, 42.3,1.2) ==
comp_success(42.3,1.2));
+static_assert(compare_exchange_strong(42.3f, 42.3f,-16.7f) ==
comp_success(42.3f, -16.7f));
+static_assert(compare_exchange_strong(0.0, 42.3,1.2) == comp_failure(0.0));
+static_assert(compare_exchange_strong(0.0f, 42.3f,-16.7f) ==
comp_failure(0.0f));
+
+// pointers
+static_assert(compare_exchange_strong(&array[0], &array[0], &array[1]) ==
comp_success(&array[0],&array[1]));
+static_assert(compare_exchange_strong(&small_array[1], &small_array[1],
&small_array[0]) == comp_success(&small_array[1], &small_array[0]));
+static_assert(compare_exchange_strong(&array[1], &array[0], &array[1]) ==
comp_failure(&array[1]));
+static_assert(compare_exchange_strong(&small_array[0], &small_array[1],
&small_array[0]) == comp_failure(&small_array[0]));
+
+
+// --FETCH-OP--
+template <typename T, typename Y> consteval auto fetch_add(T original, Y arg)
-> two_values<T> {
+ _Atomic(T) av = T{original};
+ const T result = __c11_atomic_fetch_add(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __c11_atomic_load(&av, __ATOMIC_RELAXED)};
+}
+
+// integers
+static_assert(fetch_add(false, 1) == two_values{false, true});
+static_assert(fetch_add(0, 100) == two_values{0, 100});
+static_assert(fetch_add(100, -50) == two_values{100, 50});
+
+static_assert(fetch_add(int_max, 1) == two_values{int_max, int_min}); //
overflow is defined for atomic
+static_assert(fetch_add(int_min, -1) == two_values{int_min, int_max});
+
+// floats
+static_assert(fetch_add(10.3, 2.1) == two_values{10.3, 12.4});
+static_assert(fetch_add(10.3f, 2.1f) == two_values{10.3f, 12.4f});
+
+// pointers
+static_assert(fetch_add(&array[0], 1) == two_values{&array[0], &array[1]});
+static_assert(fetch_add(&small_array[0], 1) == two_values{&small_array[0],
&small_array[1]});
+static_assert(fetch_add(&array[1], 0) == two_values{&array[1], &array[1]});
+static_assert(fetch_add(&small_array[1], 0) == two_values{&small_array[1],
&small_array[1]});
+static_assert(fetch_add(&array[1], -1) == two_values{&array[1], &array[0]});
+static_assert(fetch_add(&small_array[1], -1) == two_values{&small_array[1],
&small_array[0]});
+
+template <typename T, typename Y> consteval auto fetch_sub(T original, Y arg)
-> two_values<T> {
+ _Atomic(T) av = T{original};
+ const T result = __c11_atomic_fetch_sub(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __c11_atomic_load(&av, __ATOMIC_RELAXED)};
+}
+
+// integers
+static_assert(fetch_sub(true, 1) == two_values{true, false});
+static_assert(fetch_sub(0, 100) == two_values{0, -100});
+static_assert(fetch_sub(100, -50) == two_values{100, 150});
+
+static_assert(fetch_sub(int_min, 1) == two_values{int_min, int_max}); //
overflow is defined for atomic
+static_assert(fetch_sub(int_max, -1) == two_values{int_max, int_min});
+
+// floats
+static_assert(fetch_sub(10.3, 2.3) == two_values{10.3, 8.0});
+static_assert(fetch_sub(10.3f, 2.3f) == two_values{10.3f, 8.0f});
+
+// pointers
+static_assert(fetch_sub(&array[1], 1) == two_values{&array[1], &array[0]});
+static_assert(fetch_sub(&small_array[1], 1) == two_values{&small_array[1],
&small_array[0]});
+static_assert(fetch_sub(&array[1], 0) == two_values{&array[1], &array[1]});
+static_assert(fetch_sub(&small_array[1], 0) == two_values{&small_array[1],
&small_array[1]});
+static_assert(fetch_sub(&array[0], -1) == two_values{&array[0], &array[1]});
+static_assert(fetch_sub(&small_array[0], -1) == two_values{&small_array[0],
&small_array[1]});
+
+template <typename T, typename Y> consteval auto fetch_and(T original, Y arg)
-> two_values<T> {
+ _Atomic(T) av = T{original};
+ const T result = __c11_atomic_fetch_and(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __c11_atomic_load(&av, __ATOMIC_RELAXED)};
+}
+
+template <typename T, typename Y> consteval auto fetch_or(T original, Y arg)
-> two_values<T> {
+ _Atomic(T) av = T{original};
+ const T result = __c11_atomic_fetch_or(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __c11_atomic_load(&av, __ATOMIC_RELAXED)};
+}
+
+template <typename T, typename Y> consteval auto fetch_xor(T original, Y arg)
-> two_values<T> {
+ _Atomic(T) av = T{original};
+ const T result = __c11_atomic_fetch_xor(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __c11_atomic_load(&av, __ATOMIC_RELAXED)};
+}
+
+template <typename T, typename Y> consteval auto fetch_nand(T original, Y arg)
-> two_values<T> {
+ _Atomic(T) av = T{original};
+ const T result = __c11_atomic_fetch_nand(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __c11_atomic_load(&av, __ATOMIC_RELAXED)};
+}
+
+static_assert(fetch_and(0b1101u, 0b1011u) == two_values{0b1101u, 0b1001u});
+static_assert(fetch_or(0b1101u, 0b1011u) == two_values{0b1101u, 0b1111u});
+static_assert(fetch_xor(0b1101u, 0b1011u) == two_values{0b1101u, 0b0110u});
+static_assert(fetch_nand(0b1001u, 0b1011u) == two_values{0b1001u,
0xFFFFFFF6u});
+
+template <typename T> consteval auto fetch_min(T original, T arg) ->
two_values<T> {
+ _Atomic(T) av = T{original};
+ const T result = __c11_atomic_fetch_min(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __c11_atomic_load(&av, __ATOMIC_RELAXED)};
+}
+
+template <typename T> consteval auto fetch_max(T original, T arg) ->
two_values<T> {
+ _Atomic(T) av = T{original};
+ const T result = __c11_atomic_fetch_max(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __c11_atomic_load(&av, __ATOMIC_RELAXED)};
+}
+
+static_assert(fetch_max(10, 16) == two_values{10, 16});
+static_assert(fetch_max(16, 10) == two_values{16, 16});
+
+static_assert(fetch_min(10, 16) == two_values{10, 10});
+static_assert(fetch_min(16, 10) == two_values{16, 10});
+
diff --git a/clang/test/SemaCXX/atomic-constexpr-gcc-builtins.cpp
b/clang/test/SemaCXX/atomic-constexpr-gcc-builtins.cpp
new file mode 100644
index 0000000000000..1e9ff93e313d6
--- /dev/null
+++ b/clang/test/SemaCXX/atomic-constexpr-gcc-builtins.cpp
@@ -0,0 +1,494 @@
+// RUN: %clang_cc1 -std=c++20 %s
+
+// expected-no-diagnostics
+
+constexpr int int_min = -2147483648;
+constexpr int int_max = 2147483647;
+
+const int array[2] = {1,2};
+const char small_array[2] = {1,2};
+
+template <typename T> struct identity {
+ using type = T;
+};
+
+template <typename T> using do_not_deduce = typename identity<T>::type;
+
+// -- LOAD --
+
+template <typename T> consteval T load(T value) {
+ T av = value;
+ T out{};
+ __atomic_load(&av, &out, __ATOMIC_RELAXED);
+ return out;
+}
+
+// integers
+static_assert(load(true) == true);
+static_assert(load(false) == false);
+
+static_assert(load(42) == 42);
+static_assert(load(-128) == -128);
+
+static_assert(load(42u) == 42u);
+static_assert(load(0xFFFFFFFFu) == 0xFFFFFFFFu);
+
+// pointers
+static_assert(load(&array[0]) == &array[0]);
+static_assert(load(&small_array[1]) == &small_array[1]);
+
+// -- LOAD-N --
+
+template <typename T> consteval T load_n(T value) {
+ T av = value;
+ return __atomic_load_n(&av, __ATOMIC_RELAXED);
+}
+
+// integers
+static_assert(load_n(true) == true);
+static_assert(load_n(false) == false);
+
+static_assert(load_n(42) == 42);
+static_assert(load_n(-128) == -128);
+
+static_assert(load_n(42u) == 42u);
+static_assert(load_n(0xFFFFFFFFu) == 0xFFFFFFFFu);
+
+// pointers
+static_assert(load_n(&array[0]) == &array[0]);
+static_assert(load_n(&small_array[1]) == &small_array[1]);
+
+
+// -- STORE --
+
+template <typename T> consteval T store(T value) {
+ T av = T{};
+ __atomic_store(&av, &value, __ATOMIC_RELAXED);
+ return __atomic_load_n(&av, __ATOMIC_RELAXED);
+}
+
+// integers
+static_assert(store(true) == true);
+static_assert(store(false) == false);
+
+static_assert(store(42) == 42);
+static_assert(store(-128) == -128);
+
+static_assert(store(42u) == 42u);
+static_assert(store(0xFFFFFFFFu) == 0xFFFFFFFFu);
+
+// pointers
+static_assert(store(&array[0]) == &array[0]);
+static_assert(store(&small_array[1]) == &small_array[1]);
+
+// -- STORE-N --
+
+template <typename T> consteval T store_n(T value) {
+ T av = T{};
+ __atomic_store_n(&av, value, __ATOMIC_RELAXED);
+ return __atomic_load_n(&av, __ATOMIC_RELAXED);
+}
+
+// integers
+static_assert(store_n(true) == true);
+static_assert(store_n(false) == false);
+
+static_assert(store_n(42) == 42);
+static_assert(store_n(-128) == -128);
+
+static_assert(store_n(42u) == 42u);
+static_assert(store_n(0xFFFFFFFFu) == 0xFFFFFFFFu);
+
+// pointers
+static_assert(store_n(&array[0]) == &array[0]);
+static_assert(store_n(&small_array[1]) == &small_array[1]);
+
+// -- EXCHANGE --
+template <typename T> struct two_values {
+ T before;
+ T after;
+ constexpr friend bool operator==(two_values, two_values) = default;
+};
+
+template <typename T> consteval auto exchange(T value, do_not_deduce<T>
replacement) -> two_values<T> {
+ T av = T{value};
+ T out{};
+ __atomic_exchange(&av, &replacement, &out, __ATOMIC_RELAXED);
+ return two_values<T>{out, __atomic_load_n(&av, __ATOMIC_RELAXED)};
+}
+
+// integers
+static_assert(exchange(true,false) == two_values{true, false});
+static_assert(exchange(false,true) == two_values{false, true});
+
+static_assert(exchange(10,42) == two_values{10,42});
+static_assert(exchange(14,-128) == two_values{14,-128});
+
+
+static_assert(exchange(56u,42u) == two_values{56u,42u});
+static_assert(exchange(0xFFu, 0xFFFFFFFFu) == two_values{0xFFu,0xFFFFFFFFu});
+
+// -- EXCHANGE-N --
+template <typename T> consteval auto exchange_n(T value, do_not_deduce<T>
replacement) -> two_values<T> {
+ T av = T{value};
+ T previous = __atomic_exchange_n(&av, replacement, __ATOMIC_RELAXED);
+ return two_values<T>{previous, __atomic_load_n(&av, __ATOMIC_RELAXED)};
+}
+
+// integers
+static_assert(exchange_n(true,false) == two_values{true, false});
+static_assert(exchange_n(false,true) == two_values{false, true});
+
+static_assert(exchange_n(10,42) == two_values{10,42});
+static_assert(exchange_n(14,-128) == two_values{14,-128});
+
+
+static_assert(exchange_n(56u,42u) == two_values{56u,42u});
+static_assert(exchange_n(0xFFu, 0xFFFFFFFFu) == two_values{0xFFu,0xFFFFFFFFu});
+
+// pointers
+static_assert(exchange_n(&array[0], &array[1]) ==
two_values{&array[0],&array[1]});
+static_assert(exchange_n(&small_array[1], &small_array[0]) ==
two_values{&small_array[1], &small_array[0]});
+
+// -- COMPARE-EXCHANGE --
+template <typename T> struct comp_result {
+ bool success;
+ T output;
+ T after;
+
+ constexpr comp_result(bool success_, T output_, do_not_deduce<T> after_):
success{success_}, output{output_}, after{after_} { }
+
+ constexpr friend bool operator==(comp_result, comp_result) = default;
+};
+
+template <typename T> constexpr auto comp_success(T output, do_not_deduce<T>
after) {
+ return comp_result<T>{true, output, after};
+}
+
+template <typename T> constexpr auto comp_failure(T after) {
+ return comp_result<T>{false, after, after};
+}
+
+template <typename T> consteval auto compare_exchange_weak(T original,
do_not_deduce<T> expected, do_not_deduce<T> replacement) -> comp_result<T> {
+ T av = T{original};
+ const bool success = __atomic_compare_exchange(&av, &expected, &replacement,
false, __ATOMIC_RELAXED, __ATOMIC_RELAXED);
+ return comp_result<T>{success, expected, __atomic_load_n(&av,
__ATOMIC_RELAXED)};
+}
+
+// integers
+static_assert(compare_exchange_weak(true, true, false) == comp_success(true,
false));
+static_assert(compare_exchange_weak(false, false, true) == comp_success(false,
true));
+static_assert(compare_exchange_weak(false, true, false) ==
comp_failure(false));
+static_assert(compare_exchange_weak(true, false, true) == comp_failure(true));
+
+static_assert(compare_exchange_weak(10,10,42) == comp_success(10,42));
+static_assert(compare_exchange_weak(14,14,-128) == comp_success(14,-128));
+static_assert(compare_exchange_weak(-10,10,42) == comp_failure(-10));
+static_assert(compare_exchange_weak(-14,14,-128) == comp_failure(-14));
+
+static_assert(compare_exchange_weak(56u, 56u,42u) == comp_success(56u,42u));
+static_assert(compare_exchange_weak(0xFFu, 0xFFu, 0xFFFFFFFFu) ==
comp_success(0xFFu,0xFFFFFFFFu));
+static_assert(compare_exchange_weak(3u, 56u,42u) == comp_failure(3u));
+static_assert(compare_exchange_weak(0xFu, 0xFFu, 0xFFFFFFFFu) ==
comp_failure(0xFu));
+
+// pointers
+static_assert(compare_exchange_weak(&array[0], &array[0], &array[1]) ==
comp_success(&array[0],&array[1]));
+static_assert(compare_exchange_weak(&small_array[1], &small_array[1],
&small_array[0]) == comp_success(&small_array[1], &small_array[0]));
+static_assert(compare_exchange_weak(&array[1], &array[0], &array[1]) ==
comp_failure(&array[1]));
+static_assert(compare_exchange_weak(&small_array[0], &small_array[1],
&small_array[0]) == comp_failure(&small_array[0]));
+
+
+template <typename T> consteval auto compare_exchange_strong(T original,
do_not_deduce<T> expected, do_not_deduce<T> replacement) -> comp_result<T> {
+ T av = T{original};
+ const bool success = __atomic_compare_exchange(&av, &expected, &replacement,
true, __ATOMIC_RELAXED, __ATOMIC_RELAXED);
+ return comp_result<T>{success, expected, __atomic_load_n(&av,
__ATOMIC_RELAXED)};
+}
+
+// integers
+static_assert(compare_exchange_strong(true, true, false) == comp_success(true,
false));
+static_assert(compare_exchange_strong(false, false, true) ==
comp_success(false, true));
+static_assert(compare_exchange_strong(false, true, false) ==
comp_failure(false));
+static_assert(compare_exchange_strong(true, false, true) ==
comp_failure(true));
+
+static_assert(compare_exchange_strong(10,10,42) == comp_success(10,42));
+static_assert(compare_exchange_strong(14,14,-128) == comp_success(14,-128));
+static_assert(compare_exchange_strong(-10,10,42) == comp_failure(-10));
+static_assert(compare_exchange_strong(-14,14,-128) == comp_failure(-14));
+
+static_assert(compare_exchange_strong(56u, 56u,42u) == comp_success(56u,42u));
+static_assert(compare_exchange_strong(0xFFu, 0xFFu, 0xFFFFFFFFu) ==
comp_success(0xFFu,0xFFFFFFFFu));
+static_assert(compare_exchange_strong(3u, 56u,42u) == comp_failure(3u));
+static_assert(compare_exchange_strong(0xFu, 0xFFu, 0xFFFFFFFFu) ==
comp_failure(0xFu));
+
+// pointers
+static_assert(compare_exchange_strong(&array[0], &array[0], &array[1]) ==
comp_success(&array[0],&array[1]));
+static_assert(compare_exchange_strong(&small_array[1], &small_array[1],
&small_array[0]) == comp_success(&small_array[1], &small_array[0]));
+static_assert(compare_exchange_strong(&array[1], &array[0], &array[1]) ==
comp_failure(&array[1]));
+static_assert(compare_exchange_strong(&small_array[0], &small_array[1],
&small_array[0]) == comp_failure(&small_array[0]));
+
+// --COMPARE-EXCHANGE-N--
+
+template <typename T> consteval auto compare_exchange_weak_n(T original,
do_not_deduce<T> expected, do_not_deduce<T> replacement) -> comp_result<T> {
+ T av = T{original};
+ const bool success = __atomic_compare_exchange_n(&av, &expected,
replacement, false, __ATOMIC_RELAXED, __ATOMIC_RELAXED);
+ return comp_result<T>{success, expected, __atomic_load_n(&av,
__ATOMIC_RELAXED)};
+}
+
+// integers
+static_assert(compare_exchange_weak_n(true, true, false) == comp_success(true,
false));
+static_assert(compare_exchange_weak_n(false, false, true) ==
comp_success(false, true));
+static_assert(compare_exchange_weak_n(false, true, false) ==
comp_failure(false));
+static_assert(compare_exchange_weak_n(true, false, true) ==
comp_failure(true));
+
+static_assert(compare_exchange_weak_n(10,10,42) == comp_success(10,42));
+static_assert(compare_exchange_weak_n(14,14,-128) == comp_success(14,-128));
+static_assert(compare_exchange_weak_n(-10,10,42) == comp_failure(-10));
+static_assert(compare_exchange_weak_n(-14,14,-128) == comp_failure(-14));
+
+static_assert(compare_exchange_weak_n(56u, 56u,42u) == comp_success(56u,42u));
+static_assert(compare_exchange_weak_n(0xFFu, 0xFFu, 0xFFFFFFFFu) ==
comp_success(0xFFu,0xFFFFFFFFu));
+static_assert(compare_exchange_weak_n(3u, 56u,42u) == comp_failure(3u));
+static_assert(compare_exchange_weak_n(0xFu, 0xFFu, 0xFFFFFFFFu) ==
comp_failure(0xFu));
+
+// pointers
+static_assert(compare_exchange_weak_n(&array[0], &array[0], &array[1]) ==
comp_success(&array[0],&array[1]));
+static_assert(compare_exchange_weak_n(&small_array[1], &small_array[1],
&small_array[0]) == comp_success(&small_array[1], &small_array[0]));
+static_assert(compare_exchange_weak_n(&array[1], &array[0], &array[1]) ==
comp_failure(&array[1]));
+static_assert(compare_exchange_weak_n(&small_array[0], &small_array[1],
&small_array[0]) == comp_failure(&small_array[0]));
+
+
+template <typename T> consteval auto compare_exchange_strong_n(T original,
do_not_deduce<T> expected, do_not_deduce<T> replacement) -> comp_result<T> {
+ T av = T{original};
+ const bool success = __atomic_compare_exchange_n(&av, &expected,
replacement, true, __ATOMIC_RELAXED, __ATOMIC_RELAXED);
+ return comp_result<T>{success, expected, __atomic_load_n(&av,
__ATOMIC_RELAXED)};
+}
+
+// integers
+static_assert(compare_exchange_strong_n(true, true, false) ==
comp_success(true, false));
+static_assert(compare_exchange_strong_n(false, false, true) ==
comp_success(false, true));
+static_assert(compare_exchange_strong_n(false, true, false) ==
comp_failure(false));
+static_assert(compare_exchange_strong_n(true, false, true) ==
comp_failure(true));
+
+static_assert(compare_exchange_strong_n(10,10,42) == comp_success(10,42));
+static_assert(compare_exchange_strong_n(14,14,-128) == comp_success(14,-128));
+static_assert(compare_exchange_strong_n(-10,10,42) == comp_failure(-10));
+static_assert(compare_exchange_strong_n(-14,14,-128) == comp_failure(-14));
+
+static_assert(compare_exchange_strong_n(56u, 56u,42u) ==
comp_success(56u,42u));
+static_assert(compare_exchange_strong_n(0xFFu, 0xFFu, 0xFFFFFFFFu) ==
comp_success(0xFFu,0xFFFFFFFFu));
+static_assert(compare_exchange_strong_n(3u, 56u,42u) == comp_failure(3u));
+static_assert(compare_exchange_strong_n(0xFu, 0xFFu, 0xFFFFFFFFu) ==
comp_failure(0xFu));
+
+// pointers
+static_assert(compare_exchange_strong_n(&array[0], &array[0], &array[1]) ==
comp_success(&array[0],&array[1]));
+static_assert(compare_exchange_strong_n(&small_array[1], &small_array[1],
&small_array[0]) == comp_success(&small_array[1], &small_array[0]));
+static_assert(compare_exchange_strong_n(&array[1], &array[0], &array[1]) ==
comp_failure(&array[1]));
+static_assert(compare_exchange_strong_n(&small_array[0], &small_array[1],
&small_array[0]) == comp_failure(&small_array[0]));
+
+// --FETCH-OP--
+template <typename T, typename Y> consteval auto fetch_add(T original, Y arg)
-> two_values<T> {
+ T av = T{original};
+ const T result = __atomic_fetch_add(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __atomic_load_n(&av, __ATOMIC_RELAXED)};
+}
+
+template <typename T, typename Y> consteval auto fetch_add_ptr(T original, Y
arg) -> two_values<T> {
+ T av = T{original};
+ constexpr auto pointee_size = sizeof(*static_cast<T>(nullptr));
+ arg *= pointee_size;
+ const T result = __atomic_fetch_add(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __atomic_load_n(&av, __ATOMIC_RELAXED)};
+}
+
+// integers
+static_assert(fetch_add(false, 1) == two_values{false, true});
+static_assert(fetch_add(0, 100) == two_values{0, 100});
+static_assert(fetch_add(100, -50) == two_values{100, 50});
+
+static_assert(fetch_add(int_max, 1) == two_values{int_max, int_min}); //
overflow is defined for atomic
+static_assert(fetch_add(int_min, -1) == two_values{int_min, int_max});
+
+// pointers
+static_assert(fetch_add_ptr(&array[0], 1) == two_values{&array[0], &array[1]});
+static_assert(fetch_add_ptr(&small_array[0], 1) == two_values{&small_array[0],
&small_array[1]});
+static_assert(fetch_add_ptr(&array[1], 0) == two_values{&array[1], &array[1]});
+static_assert(fetch_add_ptr(&small_array[1], 0) == two_values{&small_array[1],
&small_array[1]});
+static_assert(fetch_add_ptr(&array[1], -1) == two_values{&array[1],
&array[0]});
+static_assert(fetch_add_ptr(&small_array[1], -1) ==
two_values{&small_array[1], &small_array[0]});
+
+template <typename T, typename Y> consteval auto fetch_sub(T original, Y arg)
-> two_values<T> {
+ T av = T{original};
+ const T result = __atomic_fetch_sub(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __atomic_load_n(&av, __ATOMIC_RELAXED)};
+}
+
+template <typename T, typename Y> consteval auto fetch_sub_ptr(T original, Y
arg) -> two_values<T> {
+ T av = T{original};
+ constexpr auto pointee_size = sizeof(*static_cast<T>(nullptr));
+ arg *= pointee_size;
+ const T result = __atomic_fetch_sub(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __atomic_load_n(&av, __ATOMIC_RELAXED)};
+}
+
+// integers
+static_assert(fetch_sub(true, 1) == two_values{true, false});
+static_assert(fetch_sub(0, 100) == two_values{0, -100});
+static_assert(fetch_sub(100, -50) == two_values{100, 150});
+
+static_assert(fetch_sub(int_min, 1) == two_values{int_min, int_max}); //
overflow is defined for atomic
+static_assert(fetch_sub(int_max, -1) == two_values{int_max, int_min});
+
+// pointers
+static_assert(fetch_sub_ptr(&array[1], 1) == two_values{&array[1], &array[0]});
+static_assert(fetch_sub_ptr(&small_array[1], 1) == two_values{&small_array[1],
&small_array[0]});
+static_assert(fetch_sub_ptr(&array[1], 0) == two_values{&array[1], &array[1]});
+static_assert(fetch_sub_ptr(&small_array[1], 0) == two_values{&small_array[1],
&small_array[1]});
+static_assert(fetch_sub_ptr(&array[0], -1) == two_values{&array[0],
&array[1]});
+static_assert(fetch_sub_ptr(&small_array[0], -1) ==
two_values{&small_array[0], &small_array[1]});
+
+template <typename T, typename Y> consteval auto fetch_and(T original, Y arg)
-> two_values<T> {
+ T av = T{original};
+ const T result = __atomic_fetch_and(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __atomic_load_n(&av, __ATOMIC_RELAXED)};
+}
+
+template <typename T, typename Y> consteval auto fetch_or(T original, Y arg)
-> two_values<T> {
+ T av = T{original};
+ const T result = __atomic_fetch_or(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __atomic_load_n(&av, __ATOMIC_RELAXED)};
+}
+
+template <typename T, typename Y> consteval auto fetch_xor(T original, Y arg)
-> two_values<T> {
+ T av = T{original};
+ const T result = __atomic_fetch_xor(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __atomic_load_n(&av, __ATOMIC_RELAXED)};
+}
+
+template <typename T, typename Y> consteval auto fetch_nand(T original, Y arg)
-> two_values<T> {
+ T av = T{original};
+ const T result = __atomic_fetch_nand(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __atomic_load_n(&av, __ATOMIC_RELAXED)};
+}
+
+static_assert(fetch_and(0b1101u, 0b1011u) == two_values{0b1101u, 0b1001u});
+static_assert(fetch_or(0b1101u, 0b1011u) == two_values{0b1101u, 0b1111u});
+static_assert(fetch_xor(0b1101u, 0b1011u) == two_values{0b1101u, 0b0110u});
+static_assert(fetch_nand(0b1001u, 0b1011u) == two_values{0b1001u,
0xFFFFFFF6u});
+
+template <typename T> consteval auto fetch_min(T original, T arg) ->
two_values<T> {
+ T av = T{original};
+ const T result = __atomic_fetch_min(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __atomic_load_n(&av, __ATOMIC_RELAXED)};
+}
+
+template <typename T> consteval auto fetch_max(T original, T arg) ->
two_values<T> {
+ T av = T{original};
+ const T result = __atomic_fetch_max(&av, arg, __ATOMIC_RELAXED);
+ return two_values<T>{result, __atomic_load_n(&av, __ATOMIC_RELAXED)};
+}
+
+static_assert(fetch_max(10, 16) == two_values{10, 16});
+static_assert(fetch_max(16, 10) == two_values{16, 16});
+
+static_assert(fetch_min(10, 16) == two_values{10, 10});
+static_assert(fetch_min(16, 10) == two_values{16, 10});
+
+// --OP-FETCHP--
+template <typename T, typename Y> consteval auto add_fetch(T original, Y arg)
-> T {
+ T av = T{original};
+ return __atomic_add_fetch(&av, arg, __ATOMIC_RELAXED);
+}
+
+template <typename T, typename Y> consteval auto add_fetch_ptr(T original, Y
arg) -> T {
+ T av = T{original};
+ constexpr auto pointee_size = sizeof(*static_cast<T>(nullptr));
+ arg *= pointee_size;
+ return __atomic_add_fetch(&av, arg, __ATOMIC_RELAXED);
+}
+
+// integers
+static_assert(add_fetch(false, 1) == true);
+static_assert(add_fetch(0, 100) == 100);
+static_assert(add_fetch(100, -50) == 50);
+
+static_assert(add_fetch(int_max, 1) == int_min); // overflow is defined for
atomic
+static_assert(add_fetch(int_min, -1) == int_max);
+
+// pointers
+static_assert(add_fetch_ptr(&array[0], 1) == &array[1]);
+static_assert(add_fetch_ptr(&small_array[0], 1) == &small_array[1]);
+static_assert(add_fetch_ptr(&array[1], 0) == &array[1]);
+static_assert(add_fetch_ptr(&small_array[1], 0) == &small_array[1]);
+static_assert(add_fetch_ptr(&array[1], -1) == &array[0]);
+static_assert(add_fetch_ptr(&small_array[1], -1) ==&small_array[0]);
+
+template <typename T, typename Y> consteval auto sub_fetch(T original, Y arg)
-> T {
+ T av = T{original};
+ return __atomic_sub_fetch(&av, arg, __ATOMIC_RELAXED);
+}
+
+template <typename T, typename Y> consteval auto sub_fetch_ptr(T original, Y
arg) -> T {
+ T av = T{original};
+ constexpr auto pointee_size = sizeof(*static_cast<T>(nullptr));
+ arg *= pointee_size;
+ return __atomic_sub_fetch(&av, arg, __ATOMIC_RELAXED);
+}
+
+// integers
+static_assert(sub_fetch(true, 1) == false);
+static_assert(sub_fetch(0, 100) == -100);
+static_assert(sub_fetch(100, -50) == 150);
+
+static_assert(sub_fetch(int_min, 1) == int_max); // overflow is defined for
atomic
+static_assert(sub_fetch(int_max, -1) == int_min);
+
+// pointers
+static_assert(sub_fetch_ptr(&array[1], 1) == &array[0]);
+static_assert(sub_fetch_ptr(&small_array[1], 1) == &small_array[0]);
+static_assert(sub_fetch_ptr(&array[1], 0) == &array[1]);
+static_assert(sub_fetch_ptr(&small_array[1], 0) == &small_array[1]);
+static_assert(sub_fetch_ptr(&array[0], -1) == &array[1]);
+static_assert(sub_fetch_ptr(&small_array[0], -1) == &small_array[1]);
+
+template <typename T, typename Y> consteval auto and_fetch(T original, Y arg)
-> T {
+ T av = T{original};
+ return __atomic_and_fetch(&av, arg, __ATOMIC_RELAXED);
+}
+
+template <typename T, typename Y> consteval auto or_fetch(T original, Y arg)
-> T {
+ T av = T{original};
+ return __atomic_or_fetch(&av, arg, __ATOMIC_RELAXED);
+}
+
+template <typename T, typename Y> consteval auto xor_fetch(T original, Y arg)
-> T {
+ T av = T{original};
+ return __atomic_xor_fetch(&av, arg, __ATOMIC_RELAXED);
+}
+
+template <typename T, typename Y> consteval auto nand_fetch(T original, Y arg)
-> T {
+ T av = T{original};
+ return __atomic_nand_fetch(&av, arg, __ATOMIC_RELAXED);
+}
+
+static_assert(and_fetch(0b1101u, 0b1011u) == 0b1001u);
+static_assert(or_fetch(0b1101u, 0b1011u) == 0b1111u);
+static_assert(xor_fetch(0b1101u, 0b1011u) == 0b0110u);
+static_assert(nand_fetch(0b1001u, 0b1011u) == 0xFFFFFFF6u);
+
+template <typename T> consteval auto min_fetch(T original, T arg) -> T {
+ T av = T{original};
+ return __atomic_min_fetch(&av, arg, __ATOMIC_RELAXED);
+}
+
+template <typename T> consteval auto max_fetch(T original, T arg) -> T {
+ T av = T{original};
+ return __atomic_max_fetch(&av, arg, __ATOMIC_RELAXED);
+}
+
+static_assert(max_fetch(10, 16) == 16);
+static_assert(max_fetch(16, 10) == 16);
+
+static_assert(min_fetch(10, 16) == 10);
+static_assert(min_fetch(16, 10) == 10);
+
+
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