Compiling errors caused by turning off openmp option when building code for arm platform

[hry76519]

Hi, I found that there will be compiling error occured if I turn off the openmp in the CMakeList.txt file:
option(NCNN_OPENMP "openmp support" OFF)
The error message are as follows:

In file included from /users/lance.huang/ncnn-0920/src/layer/arm/convolution_arm.cpp:21:0:
/users/lance.huang/ncnn-0920/src/layer/arm/convolution_3x3.h: In member function ‘int ncnn::Convolution_arm::_ZNK4ncnn15Convolution_arm7forwardERKNS_3MatERS1_RKNS_6OptionE.part.14(const ncnn::Mat&, ncnn::Mat&, const ncnn::Option&) const’:
/users/lance.huang/ncnn-0920/src/layer/arm/convolution_3x3.h:12848:18: error: can’t find a register in class ‘LO_REGS’ while reloading ‘asm’
);
^
In file included from /users/lance.huang/ncnn-0920/src/layer/arm/convolution_arm.cpp:28:0:
/users/lance.huang/ncnn-0920/src/layer/arm/convolution_3x3_int8.h:3814:18: error: ‘asm’ operand has impossible constraints
);
^
/users/lance.huang/ncnn-0920/src/layer/arm/convolution_3x3_int8.h:4044:22: error: ‘asm’ operand has impossible constraints
);
^
/users/lance.huang/ncnn-0920/src/layer/arm/convolution_3x3_int8.h:5025:18: error: ‘asm’ operand has impossible constraints
);
^
/users/lance.huang/ncnn-0920/src/layer/arm/convolution_3x3_int8.h:5348:18: error: ‘asm’ operand has impossible constraints
);
^
In file included from /users/lance.huang/ncnn-0920/src/layer/arm/convolution_arm.cpp:21:0:
/users/lance.huang/ncnn-0920/src/layer/arm/convolution_3x3.h:12848:18: error: ‘asm’ operand has impossible constraints
);
^
/users/lance.huang/ncnn-0920/src/layer/arm/convolution_3x3.h:13068:22: error: ‘asm’ operand has impossible constraints
);
^
/users/lance.huang/ncnn-0920/src/layer/arm/convolution_arm.cpp:454: confused by earlier errors, bailing out
src/CMakeFiles/ncnn.dir/build.make:542: recipe for target 'src/CMakeFiles/ncnn.dir/layer/arm/convolution_arm.cpp.o' failed
make[2]: *** [src/CMakeFiles/ncnn.dir/layer/arm/convolution_arm.cpp.o] Error 1
CMakeFiles/Makefile2:302: recipe for target 'src/CMakeFiles/ncnn.dir/all' failed
make[1]: *** [src/CMakeFiles/ncnn.dir/all] Error 2
Makefile:127: recipe for target 'all' failed
make: *** [all] Error 2

The errors seem to be something wrong about the neon code.
The older version of NCNN (about three month ago) is OK for turning off OpenMP, while the recent version will get the compiling errors.

Would you please help to check and fix the problem?
Thanks.

[522730312]

可能跟你的 arm 平台有关吧，我这边倒是没有出现这个问题 armv7 用的ncnn推荐的编辑链编辑的

[nihui]

This is usually a issue in your toolchain
ask your platform vender for a toolchain upgrade