[CIR] Upstream basic CodeGen tests from incubator (#183998)

This PR upstreams `expressions.cpp` and `c89-implicit-int.c` from the
ClangIR incubator to the mainline.

Following the incremental approach discussed in #156747 and the feedback
from the closed PR #157333, I have:
1. Copied the files directly from the incubator to preserve history.
2. Updated the `RUN` lines to use the `--check-prefix=CIR` flag.
3. Converted `CHECK:` lines to `CIR:`.
4. Standardized variable captures using the `%[[VAR:.*]]` regex syntax
(in `expressions.cpp`).

Verified locally with `llvm-lit`. This is a partial fix for #156747.

*Note: As suggested in previous reviews, I am focusing only on the `CIR`
checks for now to keep the upstreaming incremental. OGCG/LLVM
verification can be added in a follow-up PR once the base tests land.*
2 files changed
tree: a0d00610146b13a58ad06d73cf88f2d4164dc932
  1. .ci/
  2. .github/
  3. bolt/
  4. clang/
  5. clang-tools-extra/
  6. cmake/
  7. compiler-rt/
  8. cross-project-tests/
  9. flang/
  10. flang-rt/
  11. libc/
  12. libclc/
  13. libcxx/
  14. libcxxabi/
  15. libsycl/
  16. libunwind/
  17. lld/
  18. lldb/
  19. llvm/
  20. llvm-libgcc/
  21. mlir/
  22. offload/
  23. openmp/
  24. orc-rt/
  25. polly/
  26. runtimes/
  27. third-party/
  28. utils/
  29. .clang-format
  30. .clang-format-ignore
  31. .clang-tidy
  32. .git-blame-ignore-revs
  33. .gitattributes
  34. .gitignore
  35. .mailmap
  36. CODE_OF_CONDUCT.md
  37. CONTRIBUTING.md
  38. LICENSE.TXT
  39. pyproject.toml
  40. README.md
  41. SECURITY.md
README.md

The LLVM Compiler Infrastructure

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Welcome to the LLVM project!

This repository contains the source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.

The LLVM project has multiple components. The core of the project is itself called “LLVM”. This contains all of the tools, libraries, and header files needed to process intermediate representations and convert them into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer.

C-like languages use the Clang frontend. This component compiles C, C++, Objective-C, and Objective-C++ code into LLVM bitcode -- and from there into object files, using LLVM.

Other components include: the libc++ C++ standard library, the LLD linker, and more.

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For information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.

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