Implement first D-specific optimization pass: -simplify-drtcalls. It uses the machinery of the standard -simplify-libcalls pass, but optimizes calls to the D runtime instead of calls to C libraries. At the moment, these optimizations are implemented by this pass: - Avoid the runtime call for `arr.length = newlen` if it can determine that the new length isn't longer than the old one. - Ditto for `cast(T[]) arr` if it will clearly always succeed. (e.g. if the length of the original array is zero, or if the old element size is a multiple of the new element size)

module tangotests.asm2;

extern(C) int printf(char*, ...);

int main()
{
    int i = 40;
    int j = 2;
    version(D_InlineAsm_X86)
    {
	asm
    	{	
        	mov EAX, i;
        	mov EBX, j;
        	add EAX, EBX;
        	mov i, EAX;
    	}
    }
    else version(D_InlineAsm_X86_64)
    {
	asm
	{
		mov EAX, i;
		mov EBX, j;
		add EAX, EBX;
		mov i, EAX;
    	}
    }
    printf("42 = %d\n", i);
    assert(i == 42);
    return 0;
}