Issue 1:
System information (version)

OpenCV => all

Operating System / Platform => ppc64le GNU/Linux

Compiler => GCC 8.2.0

Detailed description

Disabled: 10

List failed tests (first 10):

hal_intrin128.uint8x16_BASELINE :

SIMD128: void opencv_test::hal::intrin128::cpu_baseline::test_hal_intrin_uint8()
/worker/buildbot/Power9_Linux_gcc-8__opencv/opencv/modules/core/test/test_intrin_utils.hpp:295: Failure
Expected equality of these values:
data.a
Which is: { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 }
out.a
Which is: { 9, 10, 11, 12, 13, 14, 15, 16, 1, 2, 3, 4, 5, 6, 7, 8 }

hal_intrin128.int8x16_BASELINE :

SIMD128: void opencv_test::hal::intrin128::cpu_baseline::test_hal_intrin_int8()
/worker/buildbot/Power9_Linux_gcc-8__opencv/opencv/modules/core/test/test_intrin_utils.hpp:295: Failure
Expected equality of these values:
data.a
Which is: { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 }
out.a
Which is: { 9, 10, 11, 12, 13, 14, 15, 16, 1, 2, 3, 4, 5, 6, 7, 8 }

hal_intrin128.uint16x8_BASELINE :

SIMD128: void opencv_test::hal::intrin128::cpu_baseline::test_hal_intrin_uint16()
/worker/buildbot/Power9_Linux_gcc-8__opencv/opencv/modules/core/test/test_intrin_utils.hpp:295: Failure
Expected equality of these values:
data.a
Which is: { 1, 2, 3, 4, 5, 6, 7, 8 }
out.a
Which is: { 5, 6, 7, 8, 1, 2, 3, 4 }

hal_intrin128.int16x8_BASELINE :

SIMD128: void opencv_test::hal::intrin128::cpu_baseline::test_hal_intrin_int16()
/worker/buildbot/Power9_Linux_gcc-8__opencv/opencv/modules/core/test/test_intrin_utils.hpp:295: Failure
Expected equality of these values:
data.a
Which is: { 1, 2, 3, 4, 5, 6, 7, 8 }
out.a
Which is: { 5, 6, 7, 8, 1, 2, 3, 4 }

hal_intrin128.int32x4_BASELINE :

SIMD128: void opencv_test::hal::intrin128::cpu_baseline::test_hal_intrin_int32()
/worker/buildbot/Power9_Linux_gcc-8__opencv/opencv/modules/core/test/test_intrin_utils.hpp:295: Failure
Expected equality of these values:
data.a
Which is: { 1, 2, 3, 4 }
out.a
Which is: { 3, 4, 1, 2 }

hal_intrin128.uint32x4_BASELINE :

SIMD128: void opencv_test::hal::intrin128::cpu_baseline::test_hal_intrin_uint32()
/worker/buildbot/Power9_Linux_gcc-8__opencv/opencv/modules/core/test/test_intrin_utils.hpp:295: Failure
Expected equality of these values:
data.a
Which is: { 1, 2, 3, 4 }
out.a
Which is: { 3, 4, 1, 2 }

hal_intrin128.float32x4_BASELINE :

SIMD128: void opencv_test::hal::intrin128::cpu_baseline::test_hal_intrin_float32()
/worker/buildbot/Power9_Linux_gcc-8__opencv/opencv/modules/core/test/test_intrin_utils.hpp:295: Failure
Expected equality of these values:
data.a
Which is: { 1, 2, 3, 4 }
out.a
Which is: { 3, 4, 1, 2 }

CI url:

https://ocv-power.imavr.com/#/builders/10/builds/1

Steps to reproduce

build opencv on GCC 8.2 and run core accuracy test

Issue 2:
Hello im new to opencv

i have installed opencv 3.4.5 , 4.0.0 in RP3 using this guide

https://www.pyimagesearch.com/2017/10/09/optimizing-opencv-on-the-raspberry-pi/

im trying to run dnn module (yolodarknet) but im getting exactly same results after running with and without NEON and VFPU flags in the makes

now a person have reached better results without the optimizations

AlexeyAB/darknet#2093 (comment)

what am i doing wrong or how do i check ?