__m128i branchfree_search4_avx(int* source, size_t n, __m128i target) {
__m128i offsets = _mm_setzero_si128();
if(n == 0) return offsets;
__m128i ha = _mm_set1_epi32(n>>1);
while(n>1) {
n -= n>>1;
__m128i offsetsplushalf = _mm_add_epi32(offsets,ha);
ha = _mm_sub_epi32(ha,_mm_srli_epi32(ha,1));
__m128i keys = _mm_i32gather_epi32(source,offsetsplushalf,4);
__m128i lt = _mm_cmplt_epi32(keys,target);
offsets = _mm_blendv_epi8(offsets,offsetsplushalf,lt);
}
__m128i lastkeys = _mm_i32gather_epi32(source,offsets,4);
__m128i lastlt = _mm_cmplt_epi32(lastkeys,target);
__m128i oneswhereneeded = _mm_srli_epi32(lastlt,31);
__m128i answer = _mm_add_epi32(offsets,oneswhereneeded);
return answer;
}
__m128i test_mm_i32gather_epi32(int const *b, __m128i c) {
// CHECK-LABEL: test_mm_i32gather_epi32
// CHECK: call <4 x i32> @llvm.x86.avx2.gather.d.d(<4 x i32> %{{.*}}, i8* %{{.*}}, <4 x i32> %{{.*}}, <4 x i32> %{{.*}}, i8 2)
return _mm_i32gather_epi32(b, c, 2);
}
__m128i test_mm_i32gather_epi32(int const *b, __m128i c) {
// CHECK: @llvm.x86.avx2.gather.d.d
return _mm_i32gather_epi32(b, c, 2);
}
void extern
avx2_test (void)
{
x = _mm_i32gather_epi32 (base, idx, 1);
}
