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Fri, 02 May 2025 09:03:57 -0700 (PDT) Date: Fri, 2 May 2025 12:03:55 -0400 From: Yury Norov To: Ian Rogers Cc: Rasmus Villemoes , Arnd Bergmann , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Adrian Hunter , Thomas Gleixner , Jakub Kicinski , Jacob Keller , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, llvm@lists.linux.dev, Leo Yan Subject: Re: [PATCH v2 2/5] bitmap: Silence a clang -Wshorten-64-to-32 warning Message-ID: References: <20250430171534.132774-1-irogers@google.com> <20250430171534.132774-3-irogers@google.com> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250430171534.132774-3-irogers@google.com> Hi Ian, On Wed, Apr 30, 2025 at 10:15:31AM -0700, Ian Rogers wrote: > The clang warning -Wshorten-64-to-32 can be useful to catch > inadvertent truncation. In some instances this truncation can lead to > changing the sign of a result, for example, truncation to return an > int to fit a sort routine. Silence the warning by making the implicit > truncation explicit. This isn't to say the code is currently incorrect > but without silencing the warning it is hard to spot the erroneous > cases. > > Signed-off-by: Ian Rogers > --- > include/linux/bitmap.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h > index 595217b7a6e7..4395e0a618f4 100644 > --- a/include/linux/bitmap.h > +++ b/include/linux/bitmap.h > @@ -442,7 +442,7 @@ static __always_inline > unsigned int bitmap_weight(const unsigned long *src, unsigned int nbits) > { > if (small_const_nbits(nbits)) > - return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits)); > + return (int)hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits)); This should return unsigned int, I guess? Also, most of the functions you touch here have their copies in tools. Can you please keep them synchronized? Thanks, Yury > return __bitmap_weight(src, nbits); > } > > -- > 2.49.0.906.g1f30a19c02-goog