void ep2dt(epoch, date, time) double epoch;
double *date;
double *time;
{
  double dj, dj0, dj1, date0, time0, date1, epochi, epochf;
  time0 = 0.0;
  epochi = dint(epoch);
  epochf = epoch - epochi;
  date0 = epochi + 0.0101;
  date1 = epochi + 1.0101;
  dj0 = dt2jd(date0, time0);
  dj1 = dt2jd(date1, time0);
  dj = dj0 + epochf * (dj1 - dj0);
  jd2dt(dj, date, time);
  return;
}


x86 assembly (clang, -O0):
<ep2dt>:
push   %rbp
mov    %rsp,%rbp
sub    $0x60,%rsp
movsd  %xmm0,-0x8(%rbp)
mov    %rdi,-0x10(%rbp)
mov    %rsi,-0x18(%rbp)
xorps  %xmm0,%xmm0
movsd  %xmm0,-0x40(%rbp)
movsd  -0x8(%rbp),%xmm0
mov    $0x1,%al
call   1030 <dint@plt>
cvtsi2sd %eax,%xmm0
movsd  %xmm0,-0x50(%rbp)
movsd  -0x8(%rbp),%xmm0
subsd  -0x50(%rbp),%xmm0
movsd  %xmm0,-0x58(%rbp)
movsd  0xe8f(%rip),%xmm0
addsd  -0x50(%rbp),%xmm0
movsd  %xmm0,-0x38(%rbp)
movsd  0xe75(%rip),%xmm0
addsd  -0x50(%rbp),%xmm0
movsd  %xmm0,-0x48(%rbp)
movsd  -0x38(%rbp),%xmm0
movsd  -0x40(%rbp),%xmm1
mov    $0x2,%al
call   1040 <dt2jd@plt>
cvtsi2sd %eax,%xmm0
movsd  %xmm0,-0x28(%rbp)
movsd  -0x48(%rbp),%xmm0
movsd  -0x40(%rbp),%xmm1
mov    $0x2,%al
call   1040 <dt2jd@plt>
cvtsi2sd %eax,%xmm0
movsd  %xmm0,-0x30(%rbp)
movsd  -0x28(%rbp),%xmm1
movsd  -0x58(%rbp),%xmm0
movsd  -0x30(%rbp),%xmm2
subsd  -0x28(%rbp),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
movsd  %xmm0,-0x20(%rbp)
movsd  -0x20(%rbp),%xmm0
mov    -0x10(%rbp),%rdi
mov    -0x18(%rbp),%rsi
mov    $0x1,%al
call   1050 <jd2dt@plt>
add    $0x60,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<ep2dt>:
push   %r14
push   %rbx
sub    $0x18,%rsp
mov    %rsi,%r14
mov    %rdi,%rbx
movsd  %xmm0,(%rsp)
mov    $0x1,%al
call   1030 <dint@plt>
cvtsi2sd %eax,%xmm1
movsd  (%rsp),%xmm0
subsd  %xmm1,%xmm0
movsd  %xmm0,(%rsp)
movsd  0xe9d(%rip),%xmm0
addsd  %xmm1,%xmm0
addsd  0xe99(%rip),%xmm1
movsd  %xmm1,0x10(%rsp)
xorpd  %xmm1,%xmm1
mov    $0x2,%al
call   1040 <dt2jd@plt>
xorps  %xmm0,%xmm0
cvtsi2sd %eax,%xmm0
movsd  %xmm0,0x8(%rsp)
xorpd  %xmm1,%xmm1
movsd  0x10(%rsp),%xmm0
mov    $0x2,%al
call   1040 <dt2jd@plt>
xorps  %xmm0,%xmm0
cvtsi2sd %eax,%xmm0
movsd  0x8(%rsp),%xmm1
subsd  %xmm1,%xmm0
mulsd  (%rsp),%xmm0
addsd  %xmm1,%xmm0
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x1,%al
add    $0x18,%rsp
pop    %rbx
pop    %r14
jmp    1050 <jd2dt@plt>

LLVM IR (-O0):
define void @ep2dt(double %0, double* %1, double* %2) {
%4 = alloca double
%5 = alloca double*
%6 = alloca double*
%7 = alloca double
%8 = alloca double
%9 = alloca double
%10 = alloca double
%11 = alloca double
%12 = alloca double
%13 = alloca double
%14 = alloca double
store double %0, double* %4
store double* %1, double** %5
store double* %2, double** %6
store double 0.000000e+00, double* %11
%15 = load double, double* %4
%16 = call i32 (double, ...) bitcast (i32 (...)* @dint to i32 (double, ...)*)(double %15)
%17 = sitofp i32 %16 to double
store double %17, double* %13
%18 = load double, double* %4
%19 = load double, double* %13
%20 = fsub double %18, %19
store double %20, double* %14
%21 = load double, double* %13
%22 = fadd double %21, 1.010000e-02
store double %22, double* %10
%23 = load double, double* %13
%24 = fadd double %23, 1.010100e+00
store double %24, double* %12
%25 = load double, double* %10
%26 = load double, double* %11
%27 = call i32 (double, double, ...) bitcast (i32 (...)* @dt2jd to i32 (double, double, ...)*)(double %25, double %26)
%28 = sitofp i32 %27 to double
store double %28, double* %8
%29 = load double, double* %12
%30 = load double, double* %11
%31 = call i32 (double, double, ...) bitcast (i32 (...)* @dt2jd to i32 (double, double, ...)*)(double %29, double %30)
%32 = sitofp i32 %31 to double
store double %32, double* %9
%33 = load double, double* %8
%34 = load double, double* %14
%35 = load double, double* %9
%36 = load double, double* %8
%37 = fsub double %35, %36
%38 = call double @llvm.fmuladd.f64(double %34, double %37, double %33)
store double %38, double* %7
%39 = load double, double* %7
%40 = load double*, double** %5
%41 = load double*, double** %6
%42 = call i32 (double, double*, double*, ...) bitcast (i32 (...)* @jd2dt to i32 (double, double*, double*, ...)*)(double %39, double* %40, double* %41)
ret void
}

LLVM IR (-O2):
define void @ep2dt(double %0, double* %1, double* %2) {
%4 = tail call i32 (double, ...) bitcast (i32 (...)* @dint to i32 (double, ...)*)(double %0)
%5 = sitofp i32 %4 to double
%6 = fsub double %0, %5
%7 = fadd double %5, 1.010000e-02
%8 = fadd double %5, 1.010100e+00
%9 = tail call i32 (double, double, ...) bitcast (i32 (...)* @dt2jd to i32 (double, double, ...)*)(double %7, double 0.000000e+00)
%10 = sitofp i32 %9 to double
%11 = tail call i32 (double, double, ...) bitcast (i32 (...)* @dt2jd to i32 (double, double, ...)*)(double %8, double 0.000000e+00)
%12 = sitofp i32 %11 to double
%13 = fsub double %12, %10
%14 = tail call double @llvm.fmuladd.f64(double %6, double %13, double %10)
%15 = tail call i32 (double, double*, double*, ...) bitcast (i32 (...)* @jd2dt to i32 (double, double*, double*, ...)*)(double %14, double* %1, double* %2)
ret void
}