https://github.com/lntue updated https://github.com/llvm/llvm-project/pull/199808
>From b88013594ab6ed7939edd3d296b51fa0976bd1ad Mon Sep 17 00:00:00 2001 From: Tue Ly <[email protected]> Date: Wed, 27 May 2026 01:56:13 +0000 Subject: [PATCH 1/3] [clang] Make __builtin_exp and __builtin_expf constexpr. This is step 3 in https://discourse.llvm.org/t/rfc-make-clang-builtin-math-functions-constexpr-with-llvm-libc-to-support-c-23-constexpr-math-functions/86450 --- clang/include/clang/Basic/Builtins.td | 9 ++++++++- clang/lib/AST/ByteCode/InterpBuiltin.cpp | 17 ++++++++++++++++- clang/lib/AST/ExprConstant.cpp | 13 +++++++++++++ clang/test/Preprocessor/feature_tests.cpp | 4 +++- clang/test/Sema/constant-builtins-exp.cpp | 19 +++++++++++++++++++ 5 files changed, 59 insertions(+), 3 deletions(-) create mode 100644 clang/test/Sema/constant-builtins-exp.cpp diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td index 84799929cee87..0c1c12fcb5788 100644 --- a/clang/include/clang/Basic/Builtins.td +++ b/clang/include/clang/Basic/Builtins.td @@ -166,7 +166,14 @@ def ErfcF128 : Builtin { let Prototype = "__float128(__float128)"; } -def ExpF16F128 : Builtin, F16F128MathTemplate { +def BIExp : Builtin, Template<["float", "double"], ["f", ""]> { + let Spellings = ["__builtin_exp"]; + let Attributes = [FunctionWithBuiltinPrefix, NoThrow, Const, Constexpr]; + let Prototype = "T(T)"; +} + +def ExpF16F128 : Builtin, Template<["long double", "_Float16", "__float128"], + ["l", "f16", "f128"]> { let Spellings = ["__builtin_exp"]; let Attributes = [FunctionWithBuiltinPrefix, NoThrow, ConstIgnoringErrnoAndExceptions]; let Prototype = "T(T)"; diff --git a/clang/lib/AST/ByteCode/InterpBuiltin.cpp b/clang/lib/AST/ByteCode/InterpBuiltin.cpp index 8a53ae0937782..9ecc23ac5c9aa 100644 --- a/clang/lib/AST/ByteCode/InterpBuiltin.cpp +++ b/clang/lib/AST/ByteCode/InterpBuiltin.cpp @@ -706,6 +706,13 @@ static bool interp__builtin_fpclassify(InterpState &S, CodePtr OpPC, return true; } +static bool interp__builtin_exp(InterpState &S, CodePtr OpPC, + const InterpFrame *Frame) { + APFloat Result = exp(S.Stk.peek<Floating>().getAPFloat()); + S.Stk.push<Floating>(Floating(Result)); + return true; +} + static inline Floating abs(InterpState &S, const Floating &In) { if (!In.isNegative()) return In; @@ -4488,7 +4495,15 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const CallExpr *Call, case Builtin::BI__builtin_copysignf128: return interp__builtin_copysign(S, OpPC, Frame); - case Builtin::BI__builtin_fmin: + case Builtin::BI__builtin_exp: + case Builtin::BI__builtin_expf: + return interp__builtin_exp(S, OpPC, Frame); + case Builtin::BI__builtin_expl: + case Builtin::BI__builtin_expf16: + case Builtin::BI__builtin_expf128: + return false + + case Builtin::BI__builtin_fmin: case Builtin::BI__builtin_fminf: case Builtin::BI__builtin_fminl: case Builtin::BI__builtin_fminf16: diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index 0522d6f1dc944..54cd1dbc937c0 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -19948,6 +19948,19 @@ bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) { return true; } + case Builtin::BI__builtin_exp: + case Builtin::BI__builtin_expf: { + APFloat Input(0.); + if (!EvaluateFloat(E->getArg(0), Input, Info)) + return false; + Result = exp(Input); + return true; + } + case Builtin::BI__builtin_expl: + case Builtin::BI__builtin_expf16: + case Builtin::BI__builtin_expf128: + return false; + case Builtin::BI__builtin_fmax: case Builtin::BI__builtin_fmaxf: case Builtin::BI__builtin_fmaxl: diff --git a/clang/test/Preprocessor/feature_tests.cpp b/clang/test/Preprocessor/feature_tests.cpp index 029f446113af4..b49376a14644f 100644 --- a/clang/test/Preprocessor/feature_tests.cpp +++ b/clang/test/Preprocessor/feature_tests.cpp @@ -60,7 +60,9 @@ #if !__has_constexpr_builtin(__builtin_fmax) || \ !__has_constexpr_builtin(__builtin_fmin) || \ !__has_constexpr_builtin(__builtin_fmaximum_num) || \ - !__has_constexpr_builtin(__builtin_fminimum_num) + !__has_constexpr_builtin(__builtin_fminimum_num) || \ + !__has_constexpr_builtin(__builtin_exp) || \ + !__has_constexpr_builtin(__builtin_expf) #error Clang should have these constexpr builtins #endif diff --git a/clang/test/Sema/constant-builtins-exp.cpp b/clang/test/Sema/constant-builtins-exp.cpp new file mode 100644 index 0000000000000..215d2c2765961 --- /dev/null +++ b/clang/test/Sema/constant-builtins-exp.cpp @@ -0,0 +1,19 @@ +// RUN: %clang_cc1 -std=c++17 -fsyntax-only -verify %s +// RUN: %clang_cc1 -std=c++17 -fsyntax-only -verify -fexperimental-new-constant-interpreter %s +// expected-no-diagnostics + +constexpr float InfFloat = __builtin_inff(); +constexpr float NegInfFloat = -__builtin_inff(); + +static_assert(InfFloat == __builtin_expf(InfFloat)); +static_assert(0.0f == __builtin_expf(NegInfFloat)); +static_assert(1.0f == __builtin_expf(0.0f)); +static_assert(0x1.5bf0a8p1f == __builtin_expf(1.0f)); + +constexpr double InfDouble = __builtin_inf(); +constexpr double NegInfDouble = -__builtin_inf(); + +static_assert(InfDouble == __builtin_exp(InfDouble)); +static_assert(0.0 == __builtin_exp(NegInfDouble)); +static_assert(1.0 == __builtin_exp(0.0)); +static_assert(0x1.5bf0a8b145769p1 == __builtin_exp(1.0)); >From 101f7614419f4031b747b871dd772a7511fd0b93 Mon Sep 17 00:00:00 2001 From: Tue Ly <[email protected]> Date: Wed, 27 May 2026 02:51:36 +0000 Subject: [PATCH 2/3] Remove float and double from Exp in Builtins.td. --- clang/include/clang/Basic/Builtins.td | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td index 0c1c12fcb5788..686a67bee1fcb 100644 --- a/clang/include/clang/Basic/Builtins.td +++ b/clang/include/clang/Basic/Builtins.td @@ -4134,7 +4134,7 @@ def Erfc : FPMathTemplate, LibBuiltin<"math.h"> { let AddBuiltinPrefixedAlias = 1; } -def Exp : FPMathTemplate, LibBuiltin<"math.h"> { +def Exp : Template<["long double", "l"]>, LibBuiltin<"math.h"> { let Spellings = ["exp"]; let Attributes = [NoThrow, ConstIgnoringErrnoAndExceptions]; let Prototype = "T(T)"; >From 3f82fd7631e4e468093cdd1ebde7a86ee767a8a3 Mon Sep 17 00:00:00 2001 From: Tue Ly <[email protected]> Date: Wed, 27 May 2026 03:00:57 +0000 Subject: [PATCH 3/3] Fix Template. --- clang/include/clang/Basic/Builtins.td | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td index 686a67bee1fcb..c01b77c4a4cb2 100644 --- a/clang/include/clang/Basic/Builtins.td +++ b/clang/include/clang/Basic/Builtins.td @@ -4134,7 +4134,7 @@ def Erfc : FPMathTemplate, LibBuiltin<"math.h"> { let AddBuiltinPrefixedAlias = 1; } -def Exp : Template<["long double", "l"]>, LibBuiltin<"math.h"> { +def Exp : Template<["long double"], ["l"]>, LibBuiltin<"math.h"> { let Spellings = ["exp"]; let Attributes = [NoThrow, ConstIgnoringErrnoAndExceptions]; let Prototype = "T(T)"; _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
