https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117766
--- Comment #13 from Tom Lane <tgl at sss dot pgh.pa.us> --- After further experimentation, it seems to me that: * There was a behavioral change between gcc 9.3.1 and the later releases I tested. Specifically, in 9.3.1 a -march switch does not override the platform-selected default -mfpu, whereas in later releases the default -mfpu is ignored if there's -march on the command line. I don't know if this was intentional. I can work with it, but: * I still maintain that it's a bug either that -march=armv8-a doesn't imply FPU support, or that -march=armv8-a accepts the useless option +nofp and not the useful option +fp. That option behavior would be sensible if armv8-a implied FPU support as it does on aarch64, but it's broken if the arch doesn't imply that on arm32. * The ARM Options documentation page https://gcc.gnu.org/onlinedocs/gcc-14.2.0/gcc/ARM-Options.html is at least complicit in this, since it says under armv8-a ‘+nofp’ Disable the floating-point, Advanced SIMD and cryptographic instructions. without mentioning that the FP instructions aren't enabled in the first place. Also, for completeness' sake here's the full -v output from the Raspberry Pi OS compiler: $ gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/lib/gcc/arm-linux-gnueabihf/12/lto-wrapper Target: arm-linux-gnueabihf Configured with: ../src/configure -v --with-pkgversion='Raspbian 12.2.0-14+rpi1' --with-bugurl=file:///usr/share/doc/gcc-12/README.Bugs --enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2 --prefix=/usr --with-gcc-major version-only --program-suffix=-12 --program-prefix=arm-linux-gnueabihf- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-libitm --disable-libquadmath --disable-libquadmath-support --enable-plugin --with-system-zlib --enable-libphobos-checking=release --with-target-system-zlib=auto --enable-objc-gc=auto --enable-multiarch --disable-sjlj-exceptions --with-arch=armv6+fp --with-float=hard --disable-werror --enable-checking=release --build=arm-linux-gnueabihf --host=arm-linux-gnueabihf --target=arm-linux-gnueabihf Thread model: posix Supported LTO compression algorithms: zlib zstd gcc version 12.2.0 (Raspbian 12.2.0-14+rpi1)
