From e522b1d09d3536ddc15459b4259150f4a53ee65a Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Thu, 4 Apr 2024 20:16:33 -0400 Subject: [PATCH] lib/x86: increase AVX-VNNI gcc prerequisite to 12.1 Although gcc 11.1 supports AVX-VNNI, a popular distro pairs it with a binutils version that does not. Require gcc 12 instead. Resolves https://github.com/ebiggers/libdeflate/issues/365 --- lib/x86/adler32_impl.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/lib/x86/adler32_impl.h b/lib/x86/adler32_impl.h index ba559e6e..00967e87 100644 --- a/lib/x86/adler32_impl.h +++ b/lib/x86/adler32_impl.h @@ -52,8 +52,15 @@ /* * AVX-VNNI implementation. This is used on CPUs that have AVX2 and AVX-VNNI * but don't have AVX-512, for example Intel Alder Lake. + * + * Unusually for a new CPU feature, gcc added support for the AVX-VNNI + * intrinsics (in gcc 11.1) slightly before binutils added support for + * assembling AVX-VNNI instructions (in binutils 2.36). Distros can reasonably + * have gcc 11 with binutils 2.35. Because of this issue, we check for gcc 12 + * instead of gcc 11. (libdeflate supports direct compilation without a + * configure step, so checking the binutils version is not always an option.) */ -#if GCC_PREREQ(11, 1) || CLANG_PREREQ(12, 0, 13000000) || MSVC_PREREQ(1930) +#if GCC_PREREQ(12, 1) || CLANG_PREREQ(12, 0, 13000000) || MSVC_PREREQ(1930) # define adler32_x86_avx2_vnni adler32_x86_avx2_vnni # define SUFFIX _avx2_vnni # define ATTRIBUTES _target_attribute("avx2,avxvnni")