msp430: Discard order argument when using __sync_xxx for atomics#6587
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OlegHahm merged 2 commits intoRIOT-OS:masterfrom Mar 8, 2017
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msp430: Discard order argument when using __sync_xxx for atomics#6587OlegHahm merged 2 commits intoRIOT-OS:masterfrom
OlegHahm merged 2 commits intoRIOT-OS:masterfrom
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required for #5616 to build on msp430 |
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ping @kaspar030 |
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OlegHahm
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Mar 6, 2017
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Just a nit: the commit message of the second commit seems too long.
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@OlegHahm addressed commit message, ready for review |
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March 7, 2017 10:21
This line gave a -Wunused-value in gcc-4.6 before the stdatomic.h header for msp430 was modified as a workaround.
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Fixes the false positive -Wunused-value warning when building with gcc-4.6.3 on msp430.
Previously we had to explicitly ignore the value to avoid getting
The compiler mistakenly thinks that the
atomic_fetch_addcall is without side effects when used in the original implementation with the comma operator. I think it is likely a compiler bug, but the compiler is age old and I don't have any more time to spend on this.With this PR, the order argument is silently discarded by the preprocessor, instead of evaluated and the result discarded. The order argument is ignored in our implementations of the helper library anyway, and it would just bad coding practice if you pass functions with side effects as the order argument on the atomic operation, so it should not really make any difference.