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SubjectRe: [PATCH] nfp: convert nfp_eth_set_bit_config() into a macro
On Tue,  3 Oct 2017 13:05:46 -0700, Matthias Kaehlcke wrote:
> nfp_eth_set_bit_config() is marked as __always_inline to allow gcc to
> identify the 'mask' parameter as known to be constant at compile time,
> which is required to use the FIELD_GET() macro.
>
> The forced inlining does the trick for gcc, but for kernel builds with
> clang it results in undefined symbols:
>
> drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.o: In function
> `__nfp_eth_set_aneg':
> drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c:(.text+0x787):
> undefined reference to `__compiletime_assert_492'
> drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c:(.text+0x7b1):
> undefined reference to `__compiletime_assert_496'
>
> These __compiletime_assert_xyx() calls would have been optimized away if
> the compiler had seen 'mask' as a constant.
>
> Convert nfp_eth_set_bit_config() into a macro, which allows both gcc and
> clang to identify 'mask' as a compile time constant.
>
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>

:(

Is there no chance of fixing the constant propagation in the compiler?

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