Reapply "[Clang][Sema] placement new initializes typedef array with correct size (#83124)" (#89036)

When in-place new-ing a local variable of an array of trivial type, the
generated code calls 'memset' with the correct size of the array,
earlier it was generating size (squared of the typedef array + size).

The cause: typedef TYPE TArray[8]; TArray x; The type of declarator is
Tarray[8] and in SemaExprCXX.cpp::BuildCXXNew we check if it's of
typedef and of constant size then we get the original type and it works
fine for non-dependent cases.
But in case of template we do TreeTransform.h:TransformCXXNEWExpr and
there we again check the allocated type which is TArray[8] and it stays
that way, so ArraySize=(Tarray[8] type, alloc Tarray[8*type]) so the
squared size allocation.

ArraySize gets calculated earlier in TreeTransform.h so that
if(!ArraySize) condition was failing.
fix: I changed that condition to if(ArraySize).
fixes https://github.com/llvm/llvm-project/issues/41441

---------

Co-authored-by: erichkeane <ekeane@nvidia.com>
4 files changed
tree: 02b9a20b1da606dcdfb86c381a9a8662589c8763
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. libc/
  11. libclc/
  12. libcxx/
  13. libcxxabi/
  14. libunwind/
  15. lld/
  16. lldb/
  17. llvm/
  18. llvm-libgcc/
  19. mlir/
  20. offload/
  21. openmp/
  22. polly/
  23. pstl/
  24. runtimes/
  25. third-party/
  26. utils/
  27. .clang-format
  28. .clang-tidy
  29. .git-blame-ignore-revs
  30. .gitattributes
  31. .gitignore
  32. .mailmap
  33. CODE_OF_CONDUCT.md
  34. CONTRIBUTING.md
  35. LICENSE.TXT
  36. pyproject.toml
  37. README.md
  38. SECURITY.md
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