Oh, i was looking at recent fail-out from libdav1d upgrade... It seems proper course of action is to add configure.ac check for nasm supporting specific new instructions, and if not - disabling internal dav1d build (or may be swicthed to old version of it?) Right now there is already one check: ## arch dep tests ARCH=[`uname -m`] I86=[`expr "x$ARCH" : 'xi[346]86.*'`] X86=[`expr "x$ARCH" : 'x..._64*'`] if test "x$I86$X86" != "x00" ; then # Checks for ix86 programs. REQUIRE_PROG(NASM, [nasm]) # libx264 nasm fix AC_MSG_CHECKING([nasm x264 compatible]) echo "vmovdqa32 [[eax]]{k1}{z}, zmm0" > conftest.asm nasm conftest.asm -o conftest.o > /dev/null 2>&1 if test $? != 0 ; then AC_MSG_RESULT([no]) AC_MSG_WARN([libx264 built without assembly code]) X264_CFG_PARAMS="$X264_CFG_PARAMS --disable-asm" else AC_MSG_RESULT([yes]) fi rm -f conftest.asm conftest.o REQUIRE_PROG(YASM, [yasm]) fi as side note I think AC_MSG_WARN([libx264 built without assembly code]) should be read as "[libx264 will be built without assembly code" ? Now how to test all those other instructions.. I looked at https://repo.or.cz/nasm.git/blob/HEAD:/test/avx512pf.asm and followed to http://sourceware.org/git/?p=binutils-gdb.git;a=tree;f=gas/testsuite/gas/i38... some of ..those? http://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=gas/testsuite/gas/i38... vgatherpf0dpd 1024(%ecx,%ymm7,4){%k1}. ? or may be (note .intel_syntax remark! I tried intel2gas but of course it had no idea about those new instructions ...) http://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=gas/testsuite/gas/i38... vpermb xmm6{k7}, xmm5, xmm4 this works on nasm 2.14.02: echo "vpermb xmm6{k7}, xmm5, xmm4" > test.nasm nasm test.nasm hexdump test 0000000 f262 0f55 f48d 0000006 vpermb seems to be new-ish AVX-512 instruction: https://github.com/WojciechMula/base64simd/issues/5 https://en.wikipedia.org/wiki/Cannon_Lake_(microarchitecture) oh, this avx-512 series of instructions is a big ...pool of them Not all supported everywhere even on latest Intel, it seems .... But we only need nasm check, no?