> From: Bruce Richardson [mailto:[email protected]] > Sent: Monday, 9 February 2026 17.45 > > Provide a common DPDK macro for the gcc/clang builtin > __rte_assume_aligned to mark pointers as pointing to something with > known minimum alignment. > > Signed-off-by: Bruce Richardson <[email protected]> > --- > lib/eal/include/rte_common.h | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/lib/eal/include/rte_common.h > b/lib/eal/include/rte_common.h > index 573bf4f2ce..51a2eaf8b4 100644 > --- a/lib/eal/include/rte_common.h > +++ b/lib/eal/include/rte_common.h > @@ -121,6 +121,12 @@ extern "C" { > #define __rte_aligned(a) __attribute__((__aligned__(a))) > #endif > > +#ifdef RTE_TOOLCHAIN_MSVC > +#define __rte_assume_aligned(ptr, align) (ptr) > +#else > +#define __rte_assume_aligned __builtin_assume_aligned > +#endif
The GCC/Clang macro supports the optional 3rd parameter (offset), but the MSVC doesn't. Maybe it's better to pass (ptr, align) to the GCC/Clang variant, so the API consistently only supports two parameters. If the 3rd parameter ever becomes needed, it can be implemented as a new macro. Also, a short description of the macro would be nice. Did you look into using e.g. __rte_assume((ptr % 16) == 0) instead? It's relevant if it has the desired effect for MSVC, which the macro in this patch doesn't.
