How to remove some useless condition branch by using some optimization options

Hi,

I used icc to build some projects, such as ffmpeg. I disabled all compiler's optimization by using '-O0' instead of '-O3', but icc reported some error as shown below:

Part of source code is:

#define ARCH_ARM 0

    if (ARCH_ARM)
        ff_float_dsp_init_arm(fdsp);

Error messages are shown as follow:

libavutil/libavutil.a(float_dsp.o): In function `avpriv_float_dsp_init':
/export/qiang/sourceCode/ffmpeg-2.8.3/libavutil/float_dsp.c:132: undefined reference to `ff_float_dsp_init_aarch64'
/export/qiang/sourceCode/ffmpeg-2.8.3/libavutil/float_dsp.c:134: undefined reference to `ff_float_dsp_init_arm'
/export/qiang/sourceCode/ffmpeg-2.8.3/libavutil/float_dsp.c:136: undefined reference to `ff_float_dsp_init_ppc'
/export/qiang/sourceCode/ffmpeg-2.8.3/libavutil/float_dsp.c:140: undefined reference to `ff_float_dsp_init_mips'
 

If '-O3' is used, the above error messages don't exist. I want to disable all optimization options and remove useless condition branch. Which icc option is only used to remove useless condition?

The icc information is shown as follow:

Intel(R) C Intel(R) 64 Compiler XE for applications running on Intel(R) 64, Version 14.0.2.144 Build 20140120
Copyright (C) 1985-2014 Intel Corporation.  All rights reserved.
 

Thanks!