llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Timm Baeder (tbaederr) <details> <summary>Changes</summary> In C, a cast from an integer to a vector is a CK_BitCast. Implement this using the same code we use for __builtin_bit_cast. --- Full diff: https://github.com/llvm/llvm-project/pull/117547.diff 2 Files Affected: - (modified) clang/lib/AST/ByteCode/Compiler.cpp (+21-2) - (modified) clang/test/AST/ByteCode/c23.c (+25-1) ``````````diff diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp index 7cf2519d6a71fb..964df7f069df0d 100644 --- a/clang/lib/AST/ByteCode/Compiler.cpp +++ b/clang/lib/AST/ByteCode/Compiler.cpp @@ -448,6 +448,10 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *CE) { QualType SubExprTy = SubExpr->getType(); std::optional<PrimType> FromT = classify(SubExprTy); + // Casts from integer to vectors in C. + if (FromT && CE->getType()->isVectorType()) + return this->emitBuiltinBitCast(CE); + std::optional<PrimType> ToT = classify(CE->getType()); if (!FromT || !ToT) return false; @@ -6471,8 +6475,23 @@ bool Compiler<Emitter>::emitBuiltinBitCast(const CastExpr *E) { } // Get a pointer to the value-to-cast on the stack. - if (!this->visit(SubExpr)) - return false; + // For CK_LValueToRValueBitCast, this is always an lvalue and + // we later assume it to be one (i.e. a PT_Ptr). However, + // we call this function for other utility methods where + // a bitcast might be useful, so convert it to a PT_Ptr in that case. + if (SubExpr->isLValue()) { + if (!this->visit(SubExpr)) + return false; + } else if (std::optional<PrimType> FromT = classify(FromType)) { + unsigned TempOffset = allocateLocalPrimitive( + SubExpr, *FromT, /*IsConst=*/true, /*IsExtended=*/false); + if (!this->visit(SubExpr)) + return false; + if (!this->emitSetLocal(*FromT, TempOffset, E)) + return false; + if (!this->emitGetPtrLocal(TempOffset, E)) + return false; + } if (!ToT || ToT == PT_Ptr) { if (!this->emitBitCastPtr(E)) diff --git a/clang/test/AST/ByteCode/c23.c b/clang/test/AST/ByteCode/c23.c index f9157e40610cc3..5154d57f6cb9e7 100644 --- a/clang/test/AST/ByteCode/c23.c +++ b/clang/test/AST/ByteCode/c23.c @@ -1,5 +1,8 @@ // RUN: %clang_cc1 -std=c23 -fexperimental-new-constant-interpreter -verify=expected,both %s // RUN: %clang_cc1 -std=c23 -verify=ref,both %s +// RUN: %clang_cc1 -std=c23 -triple=aarch64_be-linux-gnu -fexperimental-new-constant-interpreter -verify=expected,both %s +// RUN: %clang_cc1 -std=c23 -triple=aarch64_be-linux-gnu -verify=ref,both %s + typedef typeof(nullptr) nullptr_t; @@ -23,5 +26,26 @@ char bar() { return ((struct S *)buffer)->c; } - static_assert((nullptr_t){} == 0); + +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ +# define LITTLE_END 1 +#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ +# define LITTLE_END 0 +#else +# error "huh?" +#endif + +typedef unsigned char u8x4_t __attribute__((vector_size(4))); +constexpr u8x4_t arg1 = (u8x4_t)0xCAFEBABE; // okay +#if LITTLE_END +static_assert(arg1[0] == 190); +static_assert(arg1[1] == 186); +static_assert(arg1[2] == 254); +static_assert(arg1[3] == 202); +#else +static_assert(arg1[0] == 202); +static_assert(arg1[1] == 254); +static_assert(arg1[2] == 186); +static_assert(arg1[3] == 190); +#endif `````````` </details> https://github.com/llvm/llvm-project/pull/117547 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
