[ADT] Fix signed integer overflow

[WillFroom]

Fixes the signed overflow for signed types > int after #155549, as integer promotion would result in Val * 37U being signed which would result in UB signed overflow for large values

[llvmbot]

@llvm/pr-subscribers-llvm-adt

Author: Will Froom (WillFroom)

Changes

Fixes the signed overflow for signed types > int after #155549, as integer promotion would result in Val * 37U being signed which would result in UB signed overflow for large values

---

Full diff: https://github.com/llvm/llvm-project/pull/155826.diff

1 Files Affected:

• (modified) llvm/include/llvm/ADT/DenseMapInfo.h (+2-1)

diff --git a/llvm/include/llvm/ADT/DenseMapInfo.h b/llvm/include/llvm/ADT/DenseMapInfo.h
index 930bd4baca31d..ec7a116856bb4 100644
--- a/llvm/include/llvm/ADT/DenseMapInfo.h
+++ b/llvm/include/llvm/ADT/DenseMapInfo.h
@@ -124,7 +124,8 @@ struct DenseMapInfo<
     if constexpr (std::is_unsigned_v<T> && sizeof(T) > sizeof(unsigned))
       return densemap::detail::mix(Val);
     else
-      return static_cast<unsigned>(Val * 37U);
+      return static_cast<unsigned>(Val *
+                                   static_cast<std::make_unsigned_t<T>>(37U));
   }
 
   static bool isEqual(const T &LHS, const T &RHS) { return LHS == RHS; }

[llvm-ci]

LLVM Buildbot has detected a new failure on builder llvm-clang-aarch64-darwin running on doug-worker-4 while building llvm at step 4 "cmake-configure".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/26318

Here is the relevant piece of the build log for the reference

Step 4 (cmake-configure) failure: cmake (failure)
Upon execvpe b'cmake' [b'cmake', b'-DCMAKE_C_COMPILER=clang', b'-DCMAKE_CXX_COMPILER=clang++', b'-DCMAKE_BUILD_TYPE=Release', b'-DLLVM_BUILD_TESTS=ON', b'-DLLVM_CCACHE_BUILD=ON', b'-DLLVM_ENABLE_ASSERTIONS=ON', b'-DLLVM_INCLUDE_EXAMPLES=OFF', b'-DLLVM_LIT_ARGS=--verbose --timeout=900', b'-DLLVM_TARGETS_TO_BUILD=AArch64', b'-DLLVM_ENABLE_PROJECTS=llvm;cross-project-tests;lld;clang-tools-extra;clang', b'-GNinja', b'../llvm-project/llvm'] in environment id 4365123904
:Traceback (most recent call last):
  File "/Library/Python/3.9/site-packages/twisted/internet/process.py", line 433, in _fork
    self._execChild(path, uid, gid, executable, args, environment)
  File "/Library/Python/3.9/site-packages/twisted/internet/process.py", line 504, in _execChild
    os.execvpe(executable, args, environment)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.9/lib/python3.9/os.py", line 583, in execvpe
    _execvpe(file, args, env)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.9/lib/python3.9/os.py", line 616, in _execvpe
    raise last_exc
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.9/lib/python3.9/os.py", line 607, in _execvpe
    exec_func(fullname, *argrest)
FileNotFoundError: [Errno 2] No such file or directory: b'/opt/homebrew/bin/cmake'