[dpdk-dev] [PATCH] lpm: fix build error on g++ with -O0 option

Sangjin Han sangjin at eecs.berkeley.edu
Thu Jun 1 08:01:35 CEST 2017

When rte_lpm.h is used on x86, -O0 option (no optimization at all)
given to g++ (not 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 C++ programs from building. This patch replaces
"sizeof(uint64_t)" with a constant literal "8" to work around the issue.
Tested with g++ 5.4.1.

Signed-off-by: Sangjin Han <sangjin at eecs.berkeley.edu>
 lib/librte_lpm/rte_lpm_sse.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/librte_lpm/rte_lpm_sse.h b/lib/librte_lpm/rte_lpm_sse.h
index ef33c6a..2e17df3 100644
--- a/lib/librte_lpm/rte_lpm_sse.h
+++ b/lib/librte_lpm/rte_lpm_sse.h
@@ -78,7 +78,7 @@ 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));
+	i24 = _mm_srli_si128(i24, 8);
 	ptbl = (const uint32_t *)&lpm->tbl24[(uint32_t)idx];
 	tbl[0] = *ptbl;

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