Is GCC permitted to miscompile, with -fstrict-aliasing, source which clearly flouts the assumptions of that option ? eg. #include <stdio.h> unsigned int x, y; float i, j; int r; int main() { x = 0xFFFFFFFE; y = 0xCBFFFFFE; i = *(float*)&x; j = *(float*)&y; r = i<=j; printf("result = %d\n", r); return 0; } TIA, John Parkes