[PATCH] hash: fix GFNI implementation build with GCC 12

[David Marchand]

On a system that has AVX512F and GFNI, compiling fails with:

In file included from /usr/lib/gcc/x86_64-redhat-linux/12/include/immintrin.h:71,
                 from /usr/lib/gcc/x86_64-redhat-linux/12/include/x86intrin.h:32,
                 from ../../../git/pub/dpdk.org/main/lib/eal/x86/include/rte_vect.h:31,
                 from ../../../git/pub/dpdk.org/main/lib/eal/x86/include/rte_memcpy.h:17,
                 from ../../../git/pub/dpdk.org/main/lib/mempool/rte_mempool.h:48,
                 from ../../../git/pub/dpdk.org/main/lib/mbuf/rte_mbuf.h:38,
                 from ../../../git/pub/dpdk.org/main/lib/net/rte_ip.h:33,
                 from ../../../git/pub/dpdk.org/main/lib/hash/rte_thash.h:25,
                 from ../../../git/pub/dpdk.org/main/lib/hash/rte_thash.c:7:
In function ‘_mm512_mask_permutexvar_epi8’,
    inlined from ‘__rte_thash_gfni’ at
	../../../git/pub/dpdk.org/main/lib/hash/rte_thash_x86_gfni.h:142:17,
    inlined from ‘rte_thash_gfni’ at
	../../../git/pub/dpdk.org/main/lib/hash/rte_thash_x86_gfni.h:182:20,
    inlined from ‘rte_thash_adjust_tuple’ at
	../../../git/pub/dpdk.org/main/lib/hash/rte_thash.c:784:11:
/usr/lib/gcc/x86_64-redhat-linux/12/include/avx512vbmiintrin.h:97:20:
	error: ‘tuple_bytes’ may be used uninitialized [-Werror=maybe-uninitialized]
   97 |   return (__m512i) __builtin_ia32_permvarqi512_mask ((__v64qi) __B,
      |                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   98 |                                                      (__v64qi) __A,
      |                                                      ~~~~~~~~~~~~~~
   99 |                                                      (__v64qi) __W,
      |                                                      ~~~~~~~~~~~~~~
  100 |                                                      (__mmask64) __M);
      |                                                      ~~~~~~~~~~~~~~~~

And:

In file included from ../../../git/pub/dpdk.org/main/lib/hash/rte_thash_gfni.h:17,
                 from ../../../git/pub/dpdk.org/main/lib/hash/rte_thash.h:27:
../../../git/pub/dpdk.org/main/lib/hash/rte_thash_x86_gfni.h:
	In function ‘rte_thash_adjust_tuple’:
../../../git/pub/dpdk.org/main/lib/hash/rte_thash_x86_gfni.h:91:33:
	note: ‘tuple_bytes’ was declared here
   91 |         __m512i vals, matrixes, tuple_bytes, tuple_bytes_2;
      |                                 ^~~~~~~~~~~
In function ‘_mm512_mask_permutexvar_epi8’,
    inlined from ‘__rte_thash_gfni’ at
	../../../git/pub/dpdk.org/main/lib/hash/rte_thash_x86_gfni.h:142:17,
    inlined from ‘rte_thash_gfni’ at
	../../../git/pub/dpdk.org/main/lib/hash/rte_thash_x86_gfni.h:182:20,
    inlined from ‘rte_thash_adjust_tuple’ at
	../../../git/pub/dpdk.org/main/lib/hash/rte_thash.c:784:11:
/usr/lib/gcc/x86_64-redhat-linux/12/include/avx512vbmiintrin.h:97:20:
	error: ‘permute_mask’ may be used uninitialized [-Werror=maybe-uninitialized]
   97 |   return (__m512i) __builtin_ia32_permvarqi512_mask ((__v64qi) __B,
      |                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   98 |                                                      (__v64qi) __A,
      |                                                      ~~~~~~~~~~~~~~
   99 |                                                      (__v64qi) __W,
      |                                                      ~~~~~~~~~~~~~~
  100 |                                                      (__mmask64) __M);
      |                                                      ~~~~~~~~~~~~~~~~
../../../git/pub/dpdk.org/main/lib/hash/rte_thash_x86_gfni.h:
	In function ‘rte_thash_adjust_tuple’:
../../../git/pub/dpdk.org/main/lib/hash/rte_thash_x86_gfni.h:92:30:
	note: ‘permute_mask’ was declared here
   92 |         __mmask64 load_mask, permute_mask, permute_mask_2;
      |                              ^~~~~~~~~~~~
cc1: all warnings being treated as errors

Set those variables to 0.

Fixes: 4fd8c4cb0de1 ("hash: add new Toeplitz hash implementation")
Cc: stable at dpdk.org

Signed-off-by: David Marchand <david.marchand at redhat.com>
---
 lib/hash/rte_thash_x86_gfni.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/hash/rte_thash_x86_gfni.h b/lib/hash/rte_thash_x86_gfni.h
index 880739b710..7bb76ac1bb 100644
--- a/lib/hash/rte_thash_x86_gfni.h
+++ b/lib/hash/rte_thash_x86_gfni.h
@@ -88,8 +88,10 @@ __rte_thash_gfni(const uint64_t *mtrx, const uint8_t *tuple,
 	const __m512i shift_8 = _mm512_set1_epi8(8);
 	__m512i xor_acc = _mm512_setzero_si512();
 	__m512i perm_bytes = _mm512_setzero_si512();
-	__m512i vals, matrixes, tuple_bytes, tuple_bytes_2;
-	__mmask64 load_mask, permute_mask, permute_mask_2;
+	__m512i vals, matrixes, tuple_bytes_2;
+	__m512i tuple_bytes = _mm512_setzero_si512();
+	__mmask64 load_mask, permute_mask_2;
+	__mmask64 permute_mask = 0;
 	int chunk_len = 0, i = 0;
 	uint8_t mtrx_msk;
 	const int prepend = 3;
-- 
2.39.0