llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Timm Baeder (tbaederr) <details> <summary>Changes</summary> Optionally prepare storage for the result and do the bitcast anyway, to get the right diagnostic output. --- Full diff: https://github.com/llvm/llvm-project/pull/114926.diff 2 Files Affected: - (modified) clang/lib/AST/ByteCode/Compiler.cpp (+14-4) - (modified) clang/test/AST/ByteCode/builtin-bit-cast.cpp (+7) ``````````diff diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp index 35116952901684..80f3160fd75563 100644 --- a/clang/lib/AST/ByteCode/Compiler.cpp +++ b/clang/lib/AST/ByteCode/Compiler.cpp @@ -6446,8 +6446,6 @@ bool Compiler<Emitter>::emitBuiltinBitCast(const CastExpr *E) { QualType ToType = E->getType(); std::optional<PrimType> ToT = classify(ToType); - assert(!DiscardResult && "Implement DiscardResult mode for bitcasts."); - if (ToType->isNullPtrType()) { if (!this->discard(SubExpr)) return false; @@ -6463,12 +6461,24 @@ bool Compiler<Emitter>::emitBuiltinBitCast(const CastExpr *E) { } assert(!ToType->isReferenceType()); + // Prepare storage for the result in case we discard. + if (DiscardResult && !Initializing && !ToT) { + std::optional<unsigned> LocalIndex = allocateLocal(E); + if (!LocalIndex) + return false; + if (!this->emitGetPtrLocal(*LocalIndex, E)) + return false; + } + // Get a pointer to the value-to-cast on the stack. if (!this->visit(SubExpr)) return false; - if (!ToT || ToT == PT_Ptr) - return this->emitBitCastPtr(E); + if (!ToT || ToT == PT_Ptr) { + if (!this->emitBitCastPtr(E)) + return false; + return DiscardResult ? this->emitPopPtr(E) : true; + } assert(ToT); const llvm::fltSemantics *TargetSemantics = nullptr; diff --git a/clang/test/AST/ByteCode/builtin-bit-cast.cpp b/clang/test/AST/ByteCode/builtin-bit-cast.cpp index 50382399eefc9c..c381911bc39837 100644 --- a/clang/test/AST/ByteCode/builtin-bit-cast.cpp +++ b/clang/test/AST/ByteCode/builtin-bit-cast.cpp @@ -38,6 +38,13 @@ constexpr Init round_trip(const Init &init) { return bit_cast<Init>(bit_cast<Intermediate>(init)); } + +namespace Discarding { + struct S { int a; }; + constexpr int f = (__builtin_bit_cast(int, 2), 0); + constexpr int f2 = (__builtin_bit_cast(S, 2), 0); +} + namespace std { enum byte : unsigned char {}; } // namespace std `````````` </details> https://github.com/llvm/llvm-project/pull/114926 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
