[PATCH] AVX-512: Pacify -Wshift-overflow=2. [PR115409]

[Hongtao Liu]

On Mon, Jun 10, 2024 at 2:37 PM Collin Funk <collin.funk1@gmail.com> wrote:
>
> A shift of 31 on a signed int is undefined behavior.  Since unsigned
> int is 32-bits wide this change fixes it and silences the warning.
Ok.
>
> gcc/ChangeLog:
>
>         PR target/115409
>         * config/i386/avx512fp16intrin.h (_mm512_conj_pch): Make the
>         constant unsigned before shifting.
>         * config/i386/avx512fp16vlintrin.h (_mm256_conj_pch): Likewise.
>         (_mm_conj_pch): Likewise.
>
> Signed-off-by: Collin Funk <collin.funk1@gmail.com>
> ---
>  gcc/config/i386/avx512fp16intrin.h   | 2 +-
>  gcc/config/i386/avx512fp16vlintrin.h | 4 ++--
>  2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/gcc/config/i386/avx512fp16intrin.h b/gcc/config/i386/avx512fp16intrin.h
> index f86050b2087..1869a920dd3 100644
> --- a/gcc/config/i386/avx512fp16intrin.h
> +++ b/gcc/config/i386/avx512fp16intrin.h
> @@ -3355,7 +3355,7 @@ extern __inline __m512h
>  __attribute__ ((__gnu_inline__, __always_inline__, __artificial__))
>  _mm512_conj_pch (__m512h __A)
>  {
> -  return (__m512h) _mm512_xor_epi32 ((__m512i) __A, _mm512_set1_epi32 (1<<31));
> +  return (__m512h) _mm512_xor_epi32 ((__m512i) __A, _mm512_set1_epi32 (1U<<31));
>  }
>
>  extern __inline __m512h
> diff --git a/gcc/config/i386/avx512fp16vlintrin.h b/gcc/config/i386/avx512fp16vlintrin.h
> index a1e1cb567ff..405a06bbb9e 100644
> --- a/gcc/config/i386/avx512fp16vlintrin.h
> +++ b/gcc/config/i386/avx512fp16vlintrin.h
> @@ -181,7 +181,7 @@ extern __inline __m256h
>  __attribute__ ((__gnu_inline__, __always_inline__, __artificial__))
>  _mm256_conj_pch (__m256h __A)
>  {
> -  return (__m256h) _mm256_xor_epi32 ((__m256i) __A, _mm256_avx512_set1_epi32 (1<<31));
> +  return (__m256h) _mm256_xor_epi32 ((__m256i) __A, _mm256_avx512_set1_epi32 (1U<<31));
>  }
>
>  extern __inline __m256h
> @@ -209,7 +209,7 @@ extern __inline __m128h
>  __attribute__ ((__gnu_inline__, __always_inline__, __artificial__))
>  _mm_conj_pch (__m128h __A)
>  {
> -  return (__m128h) _mm_xor_epi32 ((__m128i) __A, _mm_avx512_set1_epi32 (1<<31));
> +  return (__m128h) _mm_xor_epi32 ((__m128i) __A, _mm_avx512_set1_epi32 (1U<<31));
>  }
>
>  extern __inline __m128h
> --
> 2.45.2
>


-- 
BR,
Hongtao