#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 */

/* Variables and functions */
int /*<<< orphan*/ c_sswap(int, float *, int, float *, int);
int /*<<< orphan*/ printf(char *);
float rand_float();
double tic();
double benchmark(int iterations, int len) {
  double elapsed;
  float x[len];
  float y[len];
  double t;
  int i;
  for (i = 0; i < len; i++) {
    x[i] = (rand_float() * 20000.0f) - 10000.0f;
    y[i] = 0.0f;
  }
  t = tic();
  for (i = 0; i < iterations; i++) {
    c_sswap(len, x, 1, y, 1);
    if (y[0] != y[0]) {
      printf("should not return NaN\n");
      break;
    }
  }
  elapsed = tic() - t;
  if (y[0] != y[0]) {
    printf("should not return NaN\n");
  }
  return elapsed;
}


x86 assembly (clang, -O0):
<benchmark>:
push   %rbp
mov    %rsp,%rbp
sub    $0x50,%rsp
mov    %edi,-0x4(%rbp)
mov    %esi,-0x8(%rbp)
mov    -0x8(%rbp),%eax
mov    %rsp,%rcx
mov    %rcx,-0x18(%rbp)
lea    0xf(,%rax,4),%rdx
and    $0xfffffffffffffff0,%rdx
mov    %rsp,%rcx
sub    %rdx,%rcx
mov    %rcx,-0x48(%rbp)
mov    %rcx,%rsp
mov    %rax,-0x20(%rbp)
mov    -0x8(%rbp),%eax
lea    0xf(,%rax,4),%rdx
and    $0xfffffffffffffff0,%rdx
mov    %rsp,%rcx
sub    %rdx,%rcx
mov    %rcx,-0x40(%rbp)
mov    %rcx,%rsp
mov    %rax,-0x28(%rbp)
movl   $0x0,-0x34(%rbp)
mov    -0x34(%rbp),%eax
cmp    -0x8(%rbp),%eax
jge    11f2 <benchmark+0xb2>
mov    $0x0,%al
call   1030 <rand_float@plt>
mov    -0x48(%rbp),%rcx
mov    -0x40(%rbp),%rax
movss  0xe41(%rip),%xmm1
mulss  %xmm1,%xmm0
movss  0xe39(%rip),%xmm1
addss  %xmm1,%xmm0
movslq -0x34(%rbp),%rdx
movss  %xmm0,(%rcx,%rdx,4)
movslq -0x34(%rbp),%rcx
xorps  %xmm0,%xmm0
movss  %xmm0,(%rax,%rcx,4)
mov    -0x34(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x34(%rbp)
jmp    119c <benchmark+0x5c>
mov    $0x0,%al
call   1050 <tic@plt>
movsd  %xmm0,-0x30(%rbp)
movl   $0x0,-0x34(%rbp)
mov    -0x34(%rbp),%eax
cmp    -0x4(%rbp),%eax
jge    126a <benchmark+0x12a>
mov    -0x40(%rbp),%rcx
mov    -0x48(%rbp),%rsi
mov    -0x8(%rbp),%edi
mov    $0x1,%r8d
mov    %r8d,%edx
call   1060 <c_sswap@plt>
mov    -0x40(%rbp),%rax
movss  (%rax),%xmm0
ucomiss (%rax),%xmm0
jne    1246 <benchmark+0x106>
jp     1246 <benchmark+0x106>
jmp    1257 <benchmark+0x117>
lea    0xdbb(%rip),%rdi
call   1040 <printf@plt>
jmp    126a <benchmark+0x12a>
jmp    125c <benchmark+0x11c>
mov    -0x34(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x34(%rbp)
jmp    1205 <benchmark+0xc5>
mov    $0x0,%al
call   1050 <tic@plt>
mov    -0x40(%rbp),%rax
subsd  -0x30(%rbp),%xmm0
movsd  %xmm0,-0x10(%rbp)
movss  (%rax),%xmm0
ucomiss (%rax),%xmm0
jne    1297 <benchmark+0x157>
jp     1297 <benchmark+0x157>
jmp    12a3 <benchmark+0x163>
lea    0xd6a(%rip),%rdi
call   1040 <printf@plt>
movsd  -0x10(%rbp),%xmm0
mov    -0x18(%rbp),%rax
mov    %rax,%rsp
mov    %rbp,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<benchmark>:
push   %rbp
mov    %rsp,%rbp
push   %r15
push   %r14
push   %r13
push   %r12
push   %rbx
sub    $0x18,%rsp
mov    %edi,%ebx
mov    %esi,%r13d
mov    %rsp,%r12
lea    0xf(,%r13,4),%rax
and    $0xfffffffffffffff0,%rax
sub    %rax,%r12
mov    %r12,%rsp
mov    %rsp,%r15
sub    %rax,%r15
mov    %r15,%rsp
mov    %esi,-0x30(%rbp)
test   %esi,%esi
jle    11ae <benchmark+0x6e>
xor    %r14d,%r14d
xchg   %ax,%ax
xor    %eax,%eax
call   1040 <rand_float@plt>
mulss  0xe71(%rip),%xmm0
addss  0xe6d(%rip),%xmm0
movss  %xmm0,(%r12,%r14,4)
movl   $0x0,(%r15,%r14,4)
add    $0x1,%r14
cmp    %r14,%r13
jne    1180 <benchmark+0x40>
xor    %eax,%eax
call   1050 <tic@plt>
movsd  %xmm0,-0x38(%rbp)
test   %ebx,%ebx
mov    -0x30(%rbp),%r14d
jle    1206 <benchmark+0xc6>
cs nopw 0x0(%rax,%rax,1)
nopl   0x0(%rax)
mov    %r14d,%edi
mov    %r12,%rsi
mov    $0x1,%edx
mov    %r15,%rcx
mov    $0x1,%r8d
call   1060 <c_sswap@plt>
movss  (%r15),%xmm0
ucomiss %xmm0,%xmm0
jp     11fa <benchmark+0xba>
add    $0xffffffff,%ebx
jne    11d0 <benchmark+0x90>
jmp    1206 <benchmark+0xc6>
lea    0xe07(%rip),%rdi
call   1030 <puts@plt>
xor    %eax,%eax
call   1050 <tic@plt>
movss  (%r15),%xmm1
ucomiss %xmm1,%xmm1
jp     122b <benchmark+0xeb>
subsd  -0x38(%rbp),%xmm0
lea    -0x28(%rbp),%rsp
pop    %rbx
pop    %r12
pop    %r13
pop    %r14
pop    %r15
pop    %rbp
ret
lea    0xdd6(%rip),%rdi
movsd  %xmm0,-0x30(%rbp)
call   1030 <puts@plt>
movsd  -0x30(%rbp),%xmm0
jmp    1217 <benchmark+0xd7>

LLVM IR (-O0):
@.str = [23 x i8] c"should not return NaN\0A\00"
define double @benchmark(i32 %0, i32 %1) {
%3 = alloca i32
%4 = alloca i32
%5 = alloca double
%6 = alloca i8*
%7 = alloca i64
%8 = alloca i64
%9 = alloca double
%10 = alloca i32
store i32 %0, i32* %3
store i32 %1, i32* %4
%11 = load i32, i32* %4
%12 = zext i32 %11 to i64
%13 = call i8* @llvm.stacksave()
store i8* %13, i8** %6
%14 = alloca float, i64 %12
store i64 %12, i64* %7
%15 = load i32, i32* %4
%16 = zext i32 %15 to i64
%17 = alloca float, i64 %16
store i64 %16, i64* %8
store i32 0, i32* %10
br label %18
18: ; preds = %31, %2
%19 = load i32, i32* %10
%20 = load i32, i32* %4
%21 = icmp slt i32 %19, %20
br i1 %21, label %22, label %34
22: ; preds = %18
%23 = call float (...) @rand_float()
%24 = call float @llvm.fmuladd.f32(float %23, float 2.000000e+04, float -1.000000e+04)
%25 = load i32, i32* %10
%26 = sext i32 %25 to i64
%27 = getelementptr inbounds float, float* %14, i64 %26
store float %24, float* %27
%28 = load i32, i32* %10
%29 = sext i32 %28 to i64
%30 = getelementptr inbounds float, float* %17, i64 %29
store float 0.000000e+00, float* %30
br label %31
31: ; preds = %22
%32 = load i32, i32* %10
%33 = add nsw i32 %32, 1
store i32 %33, i32* %10
br label %18
34: ; preds = %18
%35 = call double (...) @tic()
store double %35, double* %9
store i32 0, i32* %10
br label %36
36: ; preds = %51, %34
%37 = load i32, i32* %10
%38 = load i32, i32* %3
%39 = icmp slt i32 %37, %38
br i1 %39, label %40, label %54
40: ; preds = %36
%41 = load i32, i32* %4
%42 = call i32 @c_sswap(i32 %41, float* %14, i32 1, float* %17, i32 1)
%43 = getelementptr inbounds float, float* %17, i64 0
%44 = load float, float* %43
%45 = getelementptr inbounds float, float* %17, i64 0
%46 = load float, float* %45
%47 = fcmp une float %44, %46
br i1 %47, label %48, label %50
48: ; preds = %40
%49 = call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0))
br label %54
50: ; preds = %40
br label %51
51: ; preds = %50
%52 = load i32, i32* %10
%53 = add nsw i32 %52, 1
store i32 %53, i32* %10
br label %36
54: ; preds = %48, %36
%55 = call double (...) @tic()
%56 = load double, double* %9
%57 = fsub double %55, %56
store double %57, double* %5
%58 = getelementptr inbounds float, float* %17, i64 0
%59 = load float, float* %58
%60 = getelementptr inbounds float, float* %17, i64 0
%61 = load float, float* %60
%62 = fcmp une float %59, %61
br i1 %62, label %63, label %65
63: ; preds = %54
%64 = call i32 @printf(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0))
br label %65
65: ; preds = %63, %54
%66 = load double, double* %5
%67 = load i8*, i8** %6
ret double %66
}

LLVM IR (-O2):
@str.1 = [22 x i8] c"should not return NaN\00"
define double @benchmark(i32 %0, i32 %1) {
%3 = zext i32 %1 to i64
%4 = alloca float, i64 %3
%5 = alloca float, i64 %3
%6 = icmp sgt i32 %1, 0
br i1 %6, label %7, label %15
7: ; preds = %2, %7
%8 = phi i64 [ %13, %7 ], [ 0, %2 ]
%9 = tail call float (...) @rand_float()
%10 = tail call float @llvm.fmuladd.f32(float %9, float 2.000000e+04, float -1.000000e+04)
%11 = getelementptr inbounds float, float* %4, i64 %8
store float %10, float* %11
%12 = getelementptr inbounds float, float* %5, i64 %8
store float 0.000000e+00, float* %12
%13 = add nuw nsw i64 %8, 1
%14 = icmp eq i64 %13, %3
br i1 %14, label %15, label %7
15: ; preds = %7, %2
%16 = tail call double (...) @tic()
%17 = icmp sgt i32 %0, 0
br i1 %17, label %20, label %28
18: ; preds = %20
%19 = icmp eq i32 %25, %0
br i1 %19, label %28, label %20
20: ; preds = %15, %18
%21 = phi i32 [ %25, %18 ], [ 0, %15 ]
%22 = call i32 @c_sswap(i32 %1, float* %4, i32 1, float* %5, i32 1)
%23 = load float, float* %5
%24 = fcmp uno float %23, 0.000000e+00
%25 = add nuw nsw i32 %21, 1
br i1 %24, label %26, label %18
26: ; preds = %20
%27 = call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([22 x i8], [22 x i8]* @str.1, i64 0, i64 0))
br label %28
28: ; preds = %18, %15, %26
%29 = call double (...) @tic()
%30 = load float, float* %5
%31 = fcmp uno float %30, 0.000000e+00
br i1 %31, label %32, label %34
32: ; preds = %28
%33 = call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([22 x i8], [22 x i8]* @str.1, i64 0, i64 0))
br label %34
34: ; preds = %32, %28
%35 = fsub double %29, %16
ret double %35
}