[all-commits] [llvm/llvm-project] 32fc62: Reapply "Reapply "[clang][bytecode] Allocate Integ...

[Timm Baeder via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 32fc625a3fa27fa325c75b0fc841db4ce8e06805
      https://github.com/llvm/llvm-project/commit/32fc625a3fa27fa325c75b0fc841db4ce8e06805
  Author: Timm Baeder <tbaeder at redhat.com>
  Date:   2025-06-20 (Fri, 20 Jun 2025)

  Changed paths:
    M clang/lib/AST/ByteCode/ByteCodeEmitter.cpp
    M clang/lib/AST/ByteCode/Compiler.cpp
    M clang/lib/AST/ByteCode/Compiler.h
    M clang/lib/AST/ByteCode/Descriptor.cpp
    M clang/lib/AST/ByteCode/Disasm.cpp
    M clang/lib/AST/ByteCode/Floating.h
    M clang/lib/AST/ByteCode/Integral.h
    M clang/lib/AST/ByteCode/IntegralAP.h
    M clang/lib/AST/ByteCode/Interp.cpp
    M clang/lib/AST/ByteCode/Interp.h
    M clang/lib/AST/ByteCode/InterpBuiltin.cpp
    M clang/lib/AST/ByteCode/InterpBuiltinBitCast.cpp
    M clang/lib/AST/ByteCode/InterpState.h
    M clang/lib/AST/ByteCode/Opcodes.td
    M clang/lib/AST/ByteCode/PrimType.h
    M clang/lib/AST/ByteCode/Program.h
    M clang/test/AST/ByteCode/builtin-bit-cast-long-double.cpp
    M clang/test/AST/ByteCode/builtin-functions.cpp

  Log Message:
  -----------
  Reapply "Reapply "[clang][bytecode] Allocate IntegralAP and Floating … (#145014)

…types usi… (#144676)"

This reverts commit 68471d29eed2c49f9b439e505b3f24d387d54f97.

IntegralAP contains a union:
  union {
    uint64_t *Memory = nullptr;
    uint64_t Val;
  };

On 64bit systems, both Memory and Val have the same size. However, on 32
bit system, Val is 64bit and Memory only 32bit. Which means the default
initializer for Memory will only zero half of Val. We fixed this by
zero-initializing Val explicitly in the IntegralAP(unsigned BitWidth)
constructor.


See also the discussion in
https://github.com/llvm/llvm-project/pull/144246



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