https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98607
--- Comment #8 from Iain Buclaw <ibuclaw at gdcproject dot org> --- (In reply to Guillaume Piolat from comment #6) > I provide intel intrinsics API for D, these intrinsics (like in C++) allows > to change the rounding mode, and about 200 other functions that depend on > the rounding mode can be called. I'm not the one in control of who calls > what. > > I don't see a workaround for C++ headers at > https://github.com/gcc-mirror/gcc/blob/ > 16e2427f50c208dfe07d07f18009969502c25dc8/gcc/config/i386/xmmintrin.h#L872 Ah, I was mistaken last night. Probably my quick conversion was wrong in some way that prevented inlining. On a second look, you'll find nothing in xmmintrin.h that'll help you. --- #include <immintrin.h> int main() { unsigned savedRounding = _MM_GET_ROUNDING_MODE(); _MM_SET_ROUNDING_MODE(_MM_ROUND_NEAREST); union { __m128i vec; int array[4]; } A; A.vec = _mm_cvtps_epi32(_mm_setr_ps(1.4f, -2.1f, 53.5f, -2.9f)); assert(A.array[0] == 1); assert(A.array[1] == -2); assert(A.array[2] == 54); assert(A.array[3] == -3); // GCC might merge this branch with above! Despite _MM_SET_ROUNDING_MODE // not being pure. _MM_SET_ROUNDING_MODE(_MM_ROUND_DOWN); A.vec = _mm_cvtps_epi32(_mm_setr_ps(1.4f, -2.1f, 53.5f, -2.9f)); assert(A.array[0] == 1); assert(A.array[1] == -3); // fails assert(A.array[2] == 53); assert(A.array[3] == -3); return 0; } --- One workaround for the intel-intrinsics D library might be to insert a barrier in _MM_SET_ROUNDING_MODE. --- void _MM_SET_ROUNDING_MODE(int _MM_ROUND_xxxx) { asm { "" : : : "memory"; } _mm_setcsr((_mm_getcsr() & ~_MM_ROUND_MASK) | _MM_ROUND_xxxx); } ---
