Add AVX2 and AVX512 optimization for wavelet transform (#1552)

Encoder: performance gain ~0.1%​
Decoder: performance gain ~2.5%

1 files changed, 217 insertions, 7 deletions

diff --git a/src/lib/openjp2/dwt.c b/src/lib/openjp2/dwt.c
index 6b18c5dd..11aae472 100644
--- a/src/lib/openjp2/dwt.c
+++ b/src/lib/openjp2/dwt.c
@@ -52,7 +52,7 @@
 #ifdef __SSSE3__
 #include <tmmintrin.h>
 #endif
-#ifdef __AVX2__
+#if (defined(__AVX2__) || defined(__AVX512F__))
 #include <immintrin.h>
 #endif
 
@@ -66,7 +66,10 @@
 #define OPJ_WS(i) v->mem[(i)*2]
 #define OPJ_WD(i) v->mem[(1+(i)*2)]
 
-#ifdef __AVX2__
+#if defined(__AVX512F__)
+/** Number of int32 values in a AVX512 register */
+#define VREG_INT_COUNT       16
+#elif defined(__AVX2__)
 /** Number of int32 values in a AVX2 register */
 #define VREG_INT_COUNT       8
 #else
@@ -331,6 +334,51 @@ static void opj_dwt_decode_1(const opj_dwt_t *v)
 
 #endif /* STANDARD_SLOW_VERSION */
 
+#if defined(__AVX512F__)
+static int32_t loop_short_sse(int32_t len, const int32_t** lf_ptr,
+                              const int32_t** hf_ptr, int32_t** out_ptr,
+                              int32_t* prev_even)
+{
+    int32_t next_even;
+    __m128i odd, even_m1, unpack1, unpack2;
+    const int32_t batch = (len - 2) / 8;
+    const __m128i two = _mm_set1_epi32(2);
+
+    for (int32_t i = 0; i < batch; i++) {
+        const __m128i lf_ = _mm_loadu_si128((__m128i*)(*lf_ptr + 1));
+        const __m128i hf1_ = _mm_loadu_si128((__m128i*)(*hf_ptr));
+        const __m128i hf2_ = _mm_loadu_si128((__m128i*)(*hf_ptr + 1));
+
+        __m128i even = _mm_add_epi32(hf1_, hf2_);
+        even = _mm_add_epi32(even, two);
+        even = _mm_srai_epi32(even, 2);
+        even = _mm_sub_epi32(lf_, even);
+
+        next_even = _mm_extract_epi32(even, 3);
+        even_m1 = _mm_bslli_si128(even, 4);
+        even_m1 = _mm_insert_epi32(even_m1, *prev_even, 0);
+
+        //out[0] + out[2]
+        odd = _mm_add_epi32(even_m1, even);
+        odd = _mm_srai_epi32(odd, 1);
+        odd = _mm_add_epi32(odd, hf1_);
+
+        unpack1 = _mm_unpacklo_epi32(even_m1, odd);
+        unpack2 = _mm_unpackhi_epi32(even_m1, odd);
+
+        _mm_storeu_si128((__m128i*)(*out_ptr + 0), unpack1);
+        _mm_storeu_si128((__m128i*)(*out_ptr + 4), unpack2);
+
+        *prev_even = next_even;
+
+        *out_ptr += 8;
+        *lf_ptr += 4;
+        *hf_ptr += 4;
+    }
+    return batch;
+}
+#endif
+
 #if !defined(STANDARD_SLOW_VERSION)
 static void  opj_idwt53_h_cas0(OPJ_INT32* tmp,
                                const OPJ_INT32 sn,
@@ -364,6 +412,145 @@ static void  opj_idwt53_h_cas0(OPJ_INT32* tmp,
         tmp[len - 1] = in_odd[(len - 1) / 2] + tmp[len - 2];
     }
 #else
+#if defined(__AVX512F__)
+    OPJ_INT32* out_ptr = tmp;
+    int32_t prev_even = in_even[0] - ((in_odd[0] + 1) >> 1);
+
+    const __m512i permutevar_mask = _mm512_setr_epi32(
+                                        0x10, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
+                                        0x0c, 0x0d, 0x0e);
+    const __m512i store1_perm = _mm512_setr_epi64(0x00, 0x01, 0x08, 0x09, 0x02,
+                                0x03, 0x0a, 0x0b);
+    const __m512i store2_perm = _mm512_setr_epi64(0x04, 0x05, 0x0c, 0x0d, 0x06,
+                                0x07, 0x0e, 0x0f);
+
+    const __m512i two = _mm512_set1_epi32(2);
+
+    int32_t simd_batch_512 = (len - 2) / 32;
+    int32_t leftover;
+
+    for (i = 0; i < simd_batch_512; i++) {
+        const __m512i lf_avx2 = _mm512_loadu_si512((__m512i*)(in_even + 1));
+        const __m512i hf1_avx2 = _mm512_loadu_si512((__m512i*)(in_odd));
+        const __m512i hf2_avx2 = _mm512_loadu_si512((__m512i*)(in_odd + 1));
+        int32_t next_even;
+        __m512i duplicate, even_m1, odd, unpack1, unpack2, store1, store2;
+
+        __m512i even = _mm512_add_epi32(hf1_avx2, hf2_avx2);
+        even = _mm512_add_epi32(even, two);
+        even = _mm512_srai_epi32(even, 2);
+        even = _mm512_sub_epi32(lf_avx2, even);
+
+        next_even = _mm_extract_epi32(_mm512_extracti32x4_epi32(even, 3), 3);
+
+        duplicate = _mm512_set1_epi32(prev_even);
+        even_m1 = _mm512_permutex2var_epi32(even, permutevar_mask, duplicate);
+
+        //out[0] + out[2]
+        odd = _mm512_add_epi32(even_m1, even);
+        odd = _mm512_srai_epi32(odd, 1);
+        odd = _mm512_add_epi32(odd, hf1_avx2);
+
+        unpack1 = _mm512_unpacklo_epi32(even_m1, odd);
+        unpack2 = _mm512_unpackhi_epi32(even_m1, odd);
+
+        store1 = _mm512_permutex2var_epi64(unpack1, store1_perm, unpack2);
+        store2 = _mm512_permutex2var_epi64(unpack1, store2_perm, unpack2);
+
+        _mm512_storeu_si512(out_ptr, store1);
+        _mm512_storeu_si512(out_ptr + 16, store2);
+
+        prev_even = next_even;
+
+        out_ptr += 32;
+        in_even += 16;
+        in_odd += 16;
+    }
+
+    leftover = len - simd_batch_512 * 32;
+    if (leftover > 8) {
+        leftover -= 8 * loop_short_sse(leftover, &in_even, &in_odd, &out_ptr,
+                                       &prev_even);
+    }
+    out_ptr[0] = prev_even;
+
+    for (j = 1; j < (leftover - 2); j += 2) {
+        out_ptr[2] = in_even[1] - ((in_odd[0] + (in_odd[1]) + 2) >> 2);
+        out_ptr[1] = in_odd[0] + ((out_ptr[0] + out_ptr[2]) >> 1);
+        in_even++;
+        in_odd++;
+        out_ptr += 2;
+    }
+
+    if (len & 1) {
+        out_ptr[2] = in_even[1] - ((in_odd[0] + 1) >> 1);
+        out_ptr[1] = in_odd[0] + ((out_ptr[0] + out_ptr[2]) >> 1);
+    } else { //!(len & 1)
+        out_ptr[1] = in_odd[0] + out_ptr[0];
+    }
+#elif  defined(__AVX2__)
+    OPJ_INT32* out_ptr = tmp;
+    int32_t prev_even = in_even[0] - ((in_odd[0] + 1) >> 1);
+
+    const __m256i reg_permutevar_mask_move_right = _mm256_setr_epi32(0x00, 0x00,
+            0x01, 0x02, 0x03, 0x04, 0x05, 0x06);
+    const __m256i two = _mm256_set1_epi32(2);
+
+    int32_t simd_batch = (len - 2) / 16;
+    int32_t next_even;
+    __m256i even_m1, odd, unpack1_avx2, unpack2_avx2;
+
+    for (i = 0; i < simd_batch; i++) {
+        const __m256i lf_avx2 = _mm256_loadu_si256((__m256i*)(in_even + 1));
+        const __m256i hf1_avx2 = _mm256_loadu_si256((__m256i*)(in_odd));
+        const __m256i hf2_avx2 = _mm256_loadu_si256((__m256i*)(in_odd + 1));
+
+        __m256i even = _mm256_add_epi32(hf1_avx2, hf2_avx2);
+        even = _mm256_add_epi32(even, two);
+        even = _mm256_srai_epi32(even, 2);
+        even = _mm256_sub_epi32(lf_avx2, even);
+
+        next_even = _mm_extract_epi32(_mm256_extracti128_si256(even, 1), 3);
+        even_m1 = _mm256_permutevar8x32_epi32(even, reg_permutevar_mask_move_right);
+        even_m1 = _mm256_blend_epi32(even_m1, _mm256_set1_epi32(prev_even), (1 << 0));
+
+        //out[0] + out[2]
+        odd = _mm256_add_epi32(even_m1, even);
+        odd = _mm256_srai_epi32(odd, 1);
+        odd = _mm256_add_epi32(odd, hf1_avx2);
+
+        unpack1_avx2 = _mm256_unpacklo_epi32(even_m1, odd);
+        unpack2_avx2 = _mm256_unpackhi_epi32(even_m1, odd);
+
+        _mm_storeu_si128((__m128i*)(out_ptr + 0), _mm256_castsi256_si128(unpack1_avx2));
+        _mm_storeu_si128((__m128i*)(out_ptr + 4), _mm256_castsi256_si128(unpack2_avx2));
+        _mm_storeu_si128((__m128i*)(out_ptr + 8), _mm256_extracti128_si256(unpack1_avx2,
+                         0x1));
+        _mm_storeu_si128((__m128i*)(out_ptr + 12),
+                         _mm256_extracti128_si256(unpack2_avx2, 0x1));
+
+        prev_even = next_even;
+
+        out_ptr += 16;
+        in_even += 8;
+        in_odd += 8;
+    }
+    out_ptr[0] = prev_even;
+    for (j = simd_batch * 16 + 1; j < (len - 2); j += 2) {
+        out_ptr[2] = in_even[1] - ((in_odd[0] + in_odd[1] + 2) >> 2);
+        out_ptr[1] = in_odd[0] + ((out_ptr[0] + out_ptr[2]) >> 1);
+        in_even++;
+        in_odd++;
+        out_ptr += 2;
+    }
+
+    if (len & 1) {
+        out_ptr[2] = in_even[1] - ((in_odd[0] + 1) >> 1);
+        out_ptr[1] = in_odd[0] + ((out_ptr[0] + out_ptr[2]) >> 1);
+    } else { //!(len & 1)
+        out_ptr[1] = in_odd[0] + out_ptr[0];
+    }
+#else
     OPJ_INT32 d1c, d1n, s1n, s0c, s0n;
 
     assert(len > 1);
@@ -397,7 +584,8 @@ static void  opj_idwt53_h_cas0(OPJ_INT32* tmp,
     } else {
         tmp[len - 1] = d1n + s0n;
     }
-#endif
+#endif /*(__AVX512F__ || __AVX2__)*/
+#endif /*TWO_PASS_VERSION*/
     memcpy(tiledp, tmp, (OPJ_UINT32)len * sizeof(OPJ_INT32));
 }
 
@@ -511,10 +699,20 @@ static void opj_idwt53_h(const opj_dwt_t *dwt,
 #endif
 }
 
-#if (defined(__SSE2__) || defined(__AVX2__)) && !defined(STANDARD_SLOW_VERSION)
+#if (defined(__SSE2__) || defined(__AVX2__) || defined(__AVX512F__)) && !defined(STANDARD_SLOW_VERSION)
 
 /* Conveniency macros to improve the readability of the formulas */
-#if __AVX2__
+#if defined(__AVX512F__)
+#define VREG        __m512i
+#define LOAD_CST(x) _mm512_set1_epi32(x)
+#define LOAD(x)     _mm512_loadu_si512((const VREG*)(x))
+#define LOADU(x)    _mm512_loadu_si512((const VREG*)(x))
+#define STORE(x,y)  _mm512_storeu_si512((VREG*)(x),(y))
+#define STOREU(x,y) _mm512_storeu_si512((VREG*)(x),(y))
+#define ADD(x,y)    _mm512_add_epi32((x),(y))
+#define SUB(x,y)    _mm512_sub_epi32((x),(y))
+#define SAR(x,y)    _mm512_srai_epi32((x),(y))
+#elif defined(__AVX2__)
 #define VREG        __m256i
 #define LOAD_CST(x) _mm256_set1_epi32(x)
 #define LOAD(x)     _mm256_load_si256((const VREG*)(x))
@@ -576,7 +774,10 @@ static void opj_idwt53_v_cas0_mcols_SSE2_OR_AVX2(
     const VREG two = LOAD_CST(2);
 
     assert(len > 1);
-#if __AVX2__
+#if defined(__AVX512F__)
+    assert(PARALLEL_COLS_53 == 32);
+    assert(VREG_INT_COUNT == 16);
+#elif defined(__AVX2__)
     assert(PARALLEL_COLS_53 == 16);
     assert(VREG_INT_COUNT == 8);
 #else
@@ -584,10 +785,13 @@ static void opj_idwt53_v_cas0_mcols_SSE2_OR_AVX2(
     assert(VREG_INT_COUNT == 4);
 #endif
 
+//For AVX512 code aligned load/store is set to it's unaligned equivalents
+#if !defined(__AVX512F__)
     /* Note: loads of input even/odd values must be done in a unaligned */
     /* fashion. But stores in tmp can be done with aligned store, since */
     /* the temporary buffer is properly aligned */
     assert((OPJ_SIZE_T)tmp % (sizeof(OPJ_INT32) * VREG_INT_COUNT) == 0);
+#endif
 
     s1n_0 = LOADU(in_even + 0);
     s1n_1 = LOADU(in_even + VREG_INT_COUNT);
@@ -678,7 +882,10 @@ static void opj_idwt53_v_cas1_mcols_SSE2_OR_AVX2(
     const OPJ_INT32* in_odd = &tiledp_col[0];
 
     assert(len > 2);
-#if __AVX2__
+#if defined(__AVX512F__)
+    assert(PARALLEL_COLS_53 == 32);
+    assert(VREG_INT_COUNT == 16);
+#elif defined(__AVX2__)
     assert(PARALLEL_COLS_53 == 16);
     assert(VREG_INT_COUNT == 8);
 #else
@@ -686,10 +893,13 @@ static void opj_idwt53_v_cas1_mcols_SSE2_OR_AVX2(
     assert(VREG_INT_COUNT == 4);
 #endif
 
+//For AVX512 code aligned load/store is set to it's unaligned equivalents
+#if !defined(__AVX512F__)
     /* Note: loads of input even/odd values must be done in a unaligned */
     /* fashion. But stores in tmp can be done with aligned store, since */
     /* the temporary buffer is properly aligned */
     assert((OPJ_SIZE_T)tmp % (sizeof(OPJ_INT32) * VREG_INT_COUNT) == 0);
+#endif
 
     s1_0 = LOADU(in_even + stride);
     /* in_odd[0] - ((in_even[0] + s1 + 2) >> 2); */