#define NULL ((void *)0)
typedef unsigned long size_t; // Customize by platform.
typedef long intptr_t;
typedef unsigned long uintptr_t;
typedef long scalar_t__; // Either arithmetic or pointer type.
/* By default, we understand bool (as a convenience). */
typedef int bool;
#define false 0
#define true 1

/* Forward declarations */

/* Type definitions */
struct timeval {
  int tv_sec;
  int tv_usec;
};

/* Variables and functions */
double time_to_seconds(struct timeval *tstart, struct timeval *tfinish) {
  double t;
  t = (tfinish->tv_sec - tstart->tv_sec) +
      (tfinish->tv_usec - tstart->tv_usec) / 1e6;
  return t;
}


x86 assembly (clang, -O0):
<time_to_seconds>:
push   %rbp
mov    %rsp,%rbp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    -0x10(%rbp),%rax
mov    (%rax),%eax
mov    -0x8(%rbp),%rcx
sub    (%rcx),%eax
cvtsi2sd %eax,%xmm0
mov    -0x10(%rbp),%rax
mov    0x4(%rax),%eax
mov    -0x8(%rbp),%rcx
sub    0x4(%rcx),%eax
cvtsi2sd %eax,%xmm1
movsd  0xeca(%rip),%xmm2
divsd  %xmm2,%xmm1
addsd  %xmm1,%xmm0
movsd  %xmm0,-0x18(%rbp)
movsd  -0x18(%rbp),%xmm0
pop    %rbp
ret

x86 assembly (clang, -O2):
<time_to_seconds>:
mov    (%rsi),%eax
mov    0x4(%rsi),%ecx
sub    (%rdi),%eax
cvtsi2sd %eax,%xmm1
sub    0x4(%rdi),%ecx
cvtsi2sd %ecx,%xmm0
divsd  0xee6(%rip),%xmm0
addsd  %xmm1,%xmm0
ret

LLVM IR (-O0):
%struct.timeval = type { i32, i32 }
define double @time_to_seconds(%struct.timeval* %0, %struct.timeval* %1) {
%3 = alloca %struct.timeval*
%4 = alloca %struct.timeval*
%5 = alloca double
store %struct.timeval* %0, %struct.timeval** %3
store %struct.timeval* %1, %struct.timeval** %4
%6 = load %struct.timeval*, %struct.timeval** %4
%7 = getelementptr inbounds %struct.timeval, %struct.timeval* %6, i32 0, i32 0
%8 = load i32, i32* %7
%9 = load %struct.timeval*, %struct.timeval** %3
%10 = getelementptr inbounds %struct.timeval, %struct.timeval* %9, i32 0, i32 0
%11 = load i32, i32* %10
%12 = sub nsw i32 %8, %11
%13 = sitofp i32 %12 to double
%14 = load %struct.timeval*, %struct.timeval** %4
%15 = getelementptr inbounds %struct.timeval, %struct.timeval* %14, i32 0, i32 1
%16 = load i32, i32* %15
%17 = load %struct.timeval*, %struct.timeval** %3
%18 = getelementptr inbounds %struct.timeval, %struct.timeval* %17, i32 0, i32 1
%19 = load i32, i32* %18
%20 = sub nsw i32 %16, %19
%21 = sitofp i32 %20 to double
%22 = fdiv double %21, 1.000000e+06
%23 = fadd double %13, %22
store double %23, double* %5
%24 = load double, double* %5
ret double %24
}

LLVM IR (-O2):
%struct.timeval = type { i32, i32 }
define double @time_to_seconds(%struct.timeval* nocapture %0, %struct.timeval* nocapture %1) {
%3 = getelementptr inbounds %struct.timeval, %struct.timeval* %1, i64 0, i32 0
%4 = load i32, i32* %3
%5 = getelementptr inbounds %struct.timeval, %struct.timeval* %0, i64 0, i32 0
%6 = load i32, i32* %5
%7 = sub nsw i32 %4, %6
%8 = sitofp i32 %7 to double
%9 = getelementptr inbounds %struct.timeval, %struct.timeval* %1, i64 0, i32 1
%10 = load i32, i32* %9
%11 = getelementptr inbounds %struct.timeval, %struct.timeval* %0, i64 0, i32 1
%12 = load i32, i32* %11
%13 = sub nsw i32 %10, %12
%14 = sitofp i32 %13 to double
%15 = fdiv double %14, 1.000000e+06
%16 = fadd double %15, %8
ret double %16
}