There are a few loops I would like to direct the compiler to unroll with code like below. It is quite long and I'd rather not copy-paste.
Can #define statements define preprocessor macros?
I tried this:
#define foo \
#ifdef __GNUC__ \
#if __GNUC__ >= 8 \
#pragma GCC unroll 128 \
#pragma GCC ivdep \
#endif \
#endif \
#ifdef __clang__ \
#pragma clang loop vectorize(enable) interleave(enable) \
#endif
but when I use foo in the code cpp shows that it expands invalidly as:
#ifdef 4 #if 4 >= 8 #pragma GCC unroll 128 #pragma GCC ivdep #endif #endif #ifdef __clang__ #pragma clang loop vectorize(enable) interleave(enable) #endif
#ifdef 4 #if 4 >= 8 #pragma GCC unroll 128 #pragma GCC ivdep #endif #endif #ifdef __clang__ #pragma clang loop vectorize(enable) interleave(enable) #endif
You cannot define preprocessing directives the way you show in the question.
Yet you may be able to use the _Pragma operator for your purpose:
#if defined __GNUC__ && __GNUC__ >= 8
#define foo _Pragma("GCC unroll 128") _Pragma("GCC ivdep")
#elif defined __clang__
#define foo _Pragma("clang loop vectorize(enable) interleave(enable)")
#else
#define foo
#endif