It looks like devel/aarch64-none-elf-gcc and other aarch64 */gcc* 's suffer from https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101723
Date: Mon, 18 Apr 2022 19:36:01 UTC
In doing some experiments, it looks like I've run into: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101723 which had fixes applied to gcc9 , gcc10, and gcc11 in very late 2021-July into Aug (all after the most recent tagged release). gcc8 was already out of support or it would have had a commit too. ( aarch64-none-elf-gcc is currently at 8.4.0 .) The specific issue is that for compiles with -march=armv8-a+crc specified the result is as if the +crc had not been specified. In my context: {standard input}: Assembler messages: {standard input}:37: Error: selected processor does not support `crc32b w0,w0,w4' The description of the fixes starts with: QUOTE A change to the way gas interprets the .fpu directive in binutils-2.34 means that issuing .fpu will clear any features set by .arch_extension that apply to the floating point or simd units. This unfortunately causes problems for more recent versions of the architecture because we currently emit .arch, .arch_extension and .fpu directives at different times and try to suppress redundant changes. . . . END QUOTE So seeing the problem or not also depends on the vintage of gas in use, possibly explaining this not having been noticed before. This was reported separately in: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104439 for 11.2.0 and more and specifically for crc32b messages, but was classified as a duplicate of the earlier one listed above. As far as I can tell no tagged gcc release has the fix yet: releases/gcc-11.2.0 (2021-Jul-27, so close: 29th commit) releases/gcc-9.4.0 (2021-Jun-01) releases/gcc-10.3.0 (2021-Apr-08) This interfere with experimenting with an updated U-Boot for aarch64. === Mark Millard marklmi at yahoo.com