[ADT] Fix signed integer overflow (llvm#155826)

WillFroom · web-flow · commit a01933d58634 · 2025-08-28T13:49:18.000Z
Fixes the signed overflow for signed types > int after llvm#155549
diff --git 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; }

Original file line number	Diff line number	Diff line change
`@@ -124,7 +124,8 @@ struct DenseMapInfo<`
`124`	`124`	`if constexpr (std::is_unsigned_v<T> && sizeof(T) > sizeof(unsigned))`
`125`	`125`	`return densemap::detail::mix(Val);`
`126`	`126`	`else`
`127`		`- return static_cast<unsigned>(Val * 37U);`
	`127`	`+ return static_cast<unsigned>(Val *`
	`128`	`+ static_cast<std::make_unsigned_t<T>>(37U));`
`128`	`129`	`}`
`129`	`130`
`130`	`131`	`static bool isEqual(const T &LHS, const T &RHS) { return LHS == RHS; }`