https://github.com/ckoparkar updated https://github.com/llvm/llvm-project/pull/158048
>From 7665f0d152250b327b93a8aedc2ed9410e22277c Mon Sep 17 00:00:00 2001 From: Chaitanya Koparkar <[email protected]> Date: Thu, 11 Sep 2025 07:24:02 -0400 Subject: [PATCH 1/2] [Clang] Allow __builtin_fma/fmaf/fmal to be used in a constant expression --- clang/include/clang/Basic/Builtins.td | 2 +- clang/lib/AST/ByteCode/InterpBuiltin.cpp | 8 ++++++++ clang/lib/AST/ExprConstant.cpp | 12 ++++++++---- 3 files changed, 17 insertions(+), 5 deletions(-) diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td index 27639f06529cb..a22a6e68db83b 100644 --- a/clang/include/clang/Basic/Builtins.td +++ b/clang/include/clang/Basic/Builtins.td @@ -199,7 +199,7 @@ def FloorF16F128 : Builtin, F16F128MathTemplate { def FmaF16F128 : Builtin, F16F128MathTemplate { let Spellings = ["__builtin_fma"]; - let Attributes = [FunctionWithBuiltinPrefix, NoThrow, ConstIgnoringErrnoAndExceptions]; + let Attributes = [FunctionWithBuiltinPrefix, NoThrow, ConstIgnoringErrnoAndExceptions, Constexpr]; let Prototype = "T(T, T, T)"; } diff --git a/clang/lib/AST/ByteCode/InterpBuiltin.cpp b/clang/lib/AST/ByteCode/InterpBuiltin.cpp index a0dcdace854b9..55baa4891bb32 100644 --- a/clang/lib/AST/ByteCode/InterpBuiltin.cpp +++ b/clang/lib/AST/ByteCode/InterpBuiltin.cpp @@ -3411,6 +3411,14 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const CallExpr *Call, case clang::X86::BI__builtin_ia32_pmuludq512: return interp__builtin_ia32_pmul(S, OpPC, Call, BuiltinID); + case Builtin::BIfma: + case Builtin::BIfmal: + case Builtin::BIfmaf: + case Builtin::BI__builtin_fma: + case Builtin::BI__builtin_fmal: + case Builtin::BI__builtin_fmaf: + case Builtin::BI__builtin_fmaf16: + case Builtin::BI__builtin_fmaf128: case Builtin::BI__builtin_elementwise_fma: return interp__builtin_elementwise_triop_fp( S, OpPC, Call, diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index ca930737474df..dbff682714342 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -16346,11 +16346,15 @@ bool FloatExprEvaluator::VisitCallExpr(const CallExpr *E) { return true; } + case Builtin::BIfma: + case Builtin::BIfmal: + case Builtin::BIfmaf: + case Builtin::BI__builtin_fma: + case Builtin::BI__builtin_fmal: + case Builtin::BI__builtin_fmaf: + case Builtin::BI__builtin_fmaf16: + case Builtin::BI__builtin_fmaf128: case Builtin::BI__builtin_elementwise_fma: { - if (!E->getArg(0)->isPRValue() || !E->getArg(1)->isPRValue() || - !E->getArg(2)->isPRValue()) { - return false; - } APFloat SourceY(0.), SourceZ(0.); if (!EvaluateFloat(E->getArg(0), Result, Info) || !EvaluateFloat(E->getArg(1), SourceY, Info) || >From c61e699ff10d9c43cf78de46b31ff5b76e3134a3 Mon Sep 17 00:00:00 2001 From: Chaitanya Koparkar <[email protected]> Date: Sat, 13 Sep 2025 09:06:20 -0400 Subject: [PATCH 2/2] Make all fma variants constexpr, add tests --- clang/include/clang/Basic/Builtins.td | 2 +- clang/test/AST/ByteCode/builtin-functions.cpp | 13 +++++++++++++ 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td index a22a6e68db83b..956e76085a08f 100644 --- a/clang/include/clang/Basic/Builtins.td +++ b/clang/include/clang/Basic/Builtins.td @@ -3885,7 +3885,7 @@ def Floor : FPMathTemplate, LibBuiltin<"math.h"> { def Fma : FPMathTemplate, LibBuiltin<"math.h"> { let Spellings = ["fma"]; - let Attributes = [NoThrow, ConstIgnoringErrnoAndExceptions]; + let Attributes = [NoThrow, ConstIgnoringErrnoAndExceptions, Constexpr]; let Prototype = "T(T, T, T)"; let AddBuiltinPrefixedAlias = 1; } diff --git a/clang/test/AST/ByteCode/builtin-functions.cpp b/clang/test/AST/ByteCode/builtin-functions.cpp index f47bc49d9a1a8..961495bb2ad0a 100644 --- a/clang/test/AST/ByteCode/builtin-functions.cpp +++ b/clang/test/AST/ByteCode/builtin-functions.cpp @@ -1742,6 +1742,19 @@ namespace Invalid { // both-note {{in call to}} } +namespace Fma { + static_assert(__builtin_fma(2.0, 3.0, 4.0) == 10.0); + static_assert(__builtin_fma(200.0, 300.0, 400.0) == 60400.0); + static_assert(__builtin_fmal(2.0, 3.0, 4.0) == 10.0); + static_assert(__builtin_fmal(200.0, 300.0, 400.0) == 60400.0); + static_assert(__builtin_fmaf(2.0, 3.0, 4.0) == 10.0); + static_assert(__builtin_fmaf(200.0, 300.0, 400.0) == 60400.0); + static_assert(__builtin_fmaf16(2.0, 3.0, 4.0) == 10.0); + static_assert(__builtin_fmaf16(200.0, 300.0, 400.0) == 60416.0); + static_assert(__builtin_fmaf128(2.0, 3.0, 4.0) == 10.0); + static_assert(__builtin_fmaf128(200.0, 300.0, 400.0) == 60400.0); +} + #if __cplusplus >= 202002L namespace WithinLifetime { constexpr int a = 10; _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
