[dpdk-dev,v2] lpm: fix build error on g++ with -O0 option
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Commit Message
When rte_lpm.h is used on x86, -O0 option (no optimization at all)
given to gcc causes a compile error like this:
error: the last argument must be an 8-bit immediate
i24 = _mm_srli_si128(i24, sizeof(uint64_t));
-O0 option is useful for debugging and code coverage measurement, but
this error prevents DPDK programs from building. This patch replaces
"sizeof(uint64_t)" with a constant literal "8" to work around the issue.
The issue occurs on gcc/g++ versions from 4.8 to 5.
Signed-off-by: Sangjin Han <sangjin@eecs.berkeley.edu>
---
v2:
* Added a comment
* Updated the commit message: both gcc and g++ are affected.
---
lib/librte_lpm/rte_lpm_sse.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
Comments
On Fri, Jun 02, 2017 at 05:07:46AM +0000, Sangjin Han wrote:
> When rte_lpm.h is used on x86, -O0 option (no optimization at all)
> given to gcc causes a compile error like this:
>
> error: the last argument must be an 8-bit immediate
> i24 = _mm_srli_si128(i24, sizeof(uint64_t));
>
> -O0 option is useful for debugging and code coverage measurement, but
> this error prevents DPDK programs from building. This patch replaces
> "sizeof(uint64_t)" with a constant literal "8" to work around the issue.
> The issue occurs on gcc/g++ versions from 4.8 to 5.
>
> Signed-off-by: Sangjin Han <sangjin@eecs.berkeley.edu>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
02/06/2017 11:30, Bruce Richardson:
> On Fri, Jun 02, 2017 at 05:07:46AM +0000, Sangjin Han wrote:
> > When rte_lpm.h is used on x86, -O0 option (no optimization at all)
> > given to gcc causes a compile error like this:
> >
> > error: the last argument must be an 8-bit immediate
> > i24 = _mm_srli_si128(i24, sizeof(uint64_t));
> >
> > -O0 option is useful for debugging and code coverage measurement, but
> > this error prevents DPDK programs from building. This patch replaces
> > "sizeof(uint64_t)" with a constant literal "8" to work around the issue.
> > The issue occurs on gcc/g++ versions from 4.8 to 5.
> >
> > Signed-off-by: Sangjin Han <sangjin@eecs.berkeley.edu>
> Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Applied (with indent fix), thanks
@@ -78,7 +78,9 @@ rte_lpm_lookupx4(const struct rte_lpm *lpm, xmm_t ip, uint32_t hop[4],
/* extract values from tbl24[] */
idx = _mm_cvtsi128_si64(i24);
- i24 = _mm_srli_si128(i24, sizeof(uint64_t));
+
+ /* With -O0 option, gcc 4.8 - 5.4 fails to fold sizeof() into a constant */
+ i24 = _mm_srli_si128(i24, /* sizeof(uint64_t) */ 8);
ptbl = (const uint32_t *)&lpm->tbl24[(uint32_t)idx];
tbl[0] = *ptbl;