[Bug target/82641] Unable to enable crc32 for a certain function with target attribute on ARM (aarch32)

["arnd at linaro dot org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82641

Arnd Bergmann <arnd at linaro dot org> changed:

           What    |Removed                     |Added
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                 CC|                            |arnd at linaro dot org

--- Comment #14 from Arnd Bergmann <arnd at linaro dot org> ---
It looks like r255468 broke compilation of a couple of files in the Linux
kernel,
which use a top-level statement like

linux/arch/arm/kvm/hyp/banked-sr.c:
__asm__(".arch_extension     virt");

linux/arch/arm/kernel/xscale-cp0.c
asm("   .arch armv5te\n");

to allow compilation for a target other than the one specified by with -march=
to the compiler.

I tried using

#if GCC_VERSION >= 800000
#pragma GCC target("arch=armv5te")
#else
asm("    .arch armv5te\n");
#endif

but that results in a build failure:
/git/arm-soc/arch/arm/kernel/xscale-cp0.c:21: warning: "__ARM_ARCH" redefined
<built-in>: note: this is the location of the previous definition
/git/arm-soc/arch/arm/kernel/xscale-cp0.c:21: warning: "__ARM_FEATURE_COPROC"
redefined

and presumably would lead to the while file being built for armv5te, possibly
generating instructions that may be invalid for armv4 or armv4t outside of the
inline assembly that is known to be safe.