https://github.com/Golf0ned created https://github.com/llvm/llvm-project/pull/231331
Fixes [`159905`](https://github.com/llvm/llvm-project/issues/159905) by extending both evaluators. >From ab1c61652b927127ce97e3e1d8ef922fd465e56d Mon Sep 17 00:00:00 2001 From: Benjamin Ye <[email protected]> Date: Fri, 9 Oct 2026 16:16:50 -0500 Subject: [PATCH] [clang] support constexpr bitcasts to integer types --- clang/lib/AST/ByteCode/Compiler.cpp | 4 ++-- clang/lib/AST/ExprConstant.cpp | 11 ++++++++++- clang/test/SemaCXX/constexpr-vectors.cpp | 13 +++++++++++++ 3 files changed, 25 insertions(+), 3 deletions(-) diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp index a78bf7acf054c..7cb3ba28e8aef 100644 --- a/clang/lib/AST/ByteCode/Compiler.cpp +++ b/clang/lib/AST/ByteCode/Compiler.cpp @@ -786,8 +786,8 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *E) { } QualType SubExprTy = SubExpr->getType(); OptPrimType FromT = classify(SubExprTy); - // Casts from integer/vector to vector. - if (E->getType()->isVectorType()) + // Casts from integer/vector to vector, and from vector to integer. + if (E->getType()->isVectorType() || SubExprTy->isVectorType()) return this->emitBuiltinBitCast(E); OptPrimType ToT = classify(E->getType()); diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index 8551f4c9ae279..8f4680c9367a5 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -20214,7 +20214,6 @@ bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) { case CK_HLSLAggregateSplatCast: llvm_unreachable("invalid cast kind for integral value"); - case CK_BitCast: case CK_Dependent: case CK_LValueBitCast: case CK_ARCProduceObject: @@ -20232,6 +20231,16 @@ bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) { case CK_HLSLArrayRValue: return ExprEvaluatorBaseTy::VisitCastExpr(E); + case CK_BitCast: { + APValue Src; + if (!Evaluate(Src, Info, SubExpr)) + return false; + APValue Dst; + if (!handleRValueToRValueBitCast(Info, Dst, Src, E)) + return false; + return Success(Dst, E); + } + case CK_MemberPointerToBoolean: case CK_PointerToBoolean: case CK_IntegralToBoolean: diff --git a/clang/test/SemaCXX/constexpr-vectors.cpp b/clang/test/SemaCXX/constexpr-vectors.cpp index 1f6fe9310066e..fdc1e159dde37 100644 --- a/clang/test/SemaCXX/constexpr-vectors.cpp +++ b/clang/test/SemaCXX/constexpr-vectors.cpp @@ -835,3 +835,16 @@ void BoolVecUsage() { constexpr auto k = ~FourBoolsExtVec{true, false, true, false}; static_assert(k[0] == false && k[1] == true && k[2] == false && k[3] == true, ""); } + +// GH159905 +constexpr FourCharsVecSize ShiftVec(FourCharsVecSize a, int b) { + return (FourCharsVecSize)((int)a << b); +} + +void VecToIntegralUsage() { + static_assert((int)FourCharsVecSize{1, 2, 3, 4} == 0x04030201, ""); + static_assert((__int128)FourIntsVecSize{1, 2, 3, 4} == + (((__int128)0x400000003 << 64) | 0x200000001), ""); + static_assert((__int128)FourFloatsVecSize{1.0f, 0, 0, 0} == 0x3f800000, ""); + static_assert(ShiftVec(FourCharsVecSize{1, 0, 0, 0}, 8)[1] == 1, ""); +} _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
