#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*/ four1(double *, unsigned long, int);
double sin(double);
void realft(double *data, unsigned long n, int isign) {
  unsigned long i, i1, i2, i3, i4, np3;
  double c1 = 0.5, c2, h1r, h1i, h2r, h2i;
  double wr, wi, wpr, wpi, wtemp, theta;
  theta = 3.141592653589793 / (double)(n >> 1);
  if (isign == 1) {
    c2 = -0.5;
    four1(data, n >> 1, 1);
  } else {
    c2 = 0.5;
    theta = -theta;
  }
  wtemp = sin(0.5 * theta);
  wpr = -2.0 * wtemp * wtemp;
  wpi = sin(theta);
  wr = 1.0 + wpr;
  wi = wpi;
  np3 = n + 3;
  for (i = 2; i <= (n >> 2); i++) {
    i4 = 1 + (i3 = np3 - (i2 = 1 + (i1 = i + i - 1)));
    h1r = c1 * (data[i1] + data[i3]);
    h1i = c1 * (data[i2] - data[i4]);
    h2r = -c2 * (data[i2] + data[i4]);
    h2i = c2 * (data[i1] - data[i3]);
    data[i1] = h1r + wr * h2r - wi * h2i;
    data[i2] = h1i + wr * h2i + wi * h2r;
    data[i3] = h1r - wr * h2r + wi * h2i;
    data[i4] = -h1i + wr * h2i + wi * h2r;
    wr = (wtemp = wr) * wpr - wi * wpi + wr;
    wi = wi * wpr + wtemp * wpi + wi;
  }
  if (isign == 1) {
    data[1] = (h1r = data[1]) + data[2];
    data[2] = h1r - data[2];
  } else {
    data[1] = c1 * ((h1r = data[1]) + data[2]);
    data[2] = c1 * (h1r - data[2]);
    four1(data, n >> 1, -1);
  }
}


x86 assembly (clang, -O0):
<realft>:
push   %rbp
mov    %rsp,%rbp
sub    $0xb0,%rsp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    %edx,-0x14(%rbp)
movabs $0x3fe0000000000000,%rax
mov    %rax,-0x50(%rbp)
mov    -0x10(%rbp),%rax
shr    %rax
cvtsi2sd %rax,%xmm1
movsd  0xea8(%rip),%xmm0
divsd  %xmm1,%xmm0
movsd  %xmm0,-0xa8(%rbp)
ff
cmpl   $0x1,-0x14(%rbp)
jne    1196 <realft+0x76>
movsd  0xe9a(%rip),%xmm0
movsd  %xmm0,-0x58(%rbp)
mov    -0x8(%rbp),%rdi
mov    -0x10(%rbp),%rsi
shr    $0x1,%rsi
mov    $0x1,%edx
call   1030 <four1@plt>
jmp    11ca <realft+0xaa>
movsd  0xe6a(%rip),%xmm0
movsd  %xmm0,-0x58(%rbp)
movsd  -0xa8(%rbp),%xmm0
ff
movq   %xmm0,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm0
movsd  %xmm0,-0xa8(%rbp)
ff
movsd  0xe36(%rip),%xmm0
mulsd  -0xa8(%rbp),%xmm0
ff
call   1040 <sin@plt>
movsd  %xmm0,-0xa0(%rbp)
ff
movsd  0xe31(%rip),%xmm0
mulsd  -0xa0(%rbp),%xmm0
ff
mulsd  -0xa0(%rbp),%xmm0
ff
movsd  %xmm0,-0x90(%rbp)
ff
movsd  -0xa8(%rbp),%xmm0
ff
call   1040 <sin@plt>
movsd  %xmm0,-0x98(%rbp)
ff
movsd  0xdf4(%rip),%xmm0
addsd  -0x90(%rbp),%xmm0
ff
movsd  %xmm0,-0x80(%rbp)
movsd  -0x98(%rbp),%xmm0
ff
movsd  %xmm0,-0x88(%rbp)
ff
mov    -0x10(%rbp),%rax
add    $0x3,%rax
mov    %rax,-0x48(%rbp)
movq   $0x2,-0x20(%rbp)
mov    -0x20(%rbp),%rax
mov    -0x10(%rbp),%rcx
shr    $0x2,%rcx
cmp    %rcx,%rax
ja     150c <realft+0x3ec>
mov    -0x48(%rbp),%rax
mov    -0x20(%rbp),%rcx
add    -0x20(%rbp),%rcx
sub    $0x1,%rcx
mov    %rcx,-0x28(%rbp)
add    $0x1,%rcx
mov    %rcx,-0x30(%rbp)
sub    %rcx,%rax
mov    %rax,-0x38(%rbp)
add    $0x1,%rax
mov    %rax,-0x40(%rbp)
movsd  -0x50(%rbp),%xmm0
mov    -0x8(%rbp),%rax
mov    -0x28(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm1
mov    -0x8(%rbp),%rax
mov    -0x38(%rbp),%rcx
addsd  (%rax,%rcx,8),%xmm1
mulsd  %xmm1,%xmm0
movsd  %xmm0,-0x60(%rbp)
movsd  -0x50(%rbp),%xmm0
mov    -0x8(%rbp),%rax
mov    -0x30(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm1
mov    -0x8(%rbp),%rax
mov    -0x40(%rbp),%rcx
subsd  (%rax,%rcx,8),%xmm1
mulsd  %xmm1,%xmm0
movsd  %xmm0,-0x68(%rbp)
movsd  -0x58(%rbp),%xmm0
movq   %xmm0,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm0
mov    -0x8(%rbp),%rax
mov    -0x30(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm1
mov    -0x8(%rbp),%rax
mov    -0x40(%rbp),%rcx
addsd  (%rax,%rcx,8),%xmm1
mulsd  %xmm1,%xmm0
movsd  %xmm0,-0x70(%rbp)
movsd  -0x58(%rbp),%xmm0
mov    -0x8(%rbp),%rax
mov    -0x28(%rbp),%rcx
movsd  (%rax,%rcx,8),%xmm1
mov    -0x8(%rbp),%rax
mov    -0x38(%rbp),%rcx
subsd  (%rax,%rcx,8),%xmm1
mulsd  %xmm1,%xmm0
movsd  %xmm0,-0x78(%rbp)
movsd  -0x60(%rbp),%xmm0
movsd  -0x80(%rbp),%xmm1
movsd  -0x70(%rbp),%xmm2
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
movsd  -0x88(%rbp),%xmm0
ff
movsd  -0x78(%rbp),%xmm2
movq   %xmm0,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm0
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
mov    -0x8(%rbp),%rax
mov    -0x28(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
movsd  -0x68(%rbp),%xmm0
movsd  -0x80(%rbp),%xmm1
movsd  -0x78(%rbp),%xmm2
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
movsd  -0x88(%rbp),%xmm0
ff
movsd  -0x70(%rbp),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
mov    -0x8(%rbp),%rax
mov    -0x30(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
movsd  -0x60(%rbp),%xmm0
movsd  -0x80(%rbp),%xmm1
movsd  -0x70(%rbp),%xmm2
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
movsd  -0x88(%rbp),%xmm0
ff
movsd  -0x78(%rbp),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
mov    -0x8(%rbp),%rax
mov    -0x38(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
movsd  -0x68(%rbp),%xmm0
movq   %xmm0,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm0
movsd  -0x80(%rbp),%xmm1
movsd  -0x78(%rbp),%xmm2
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
movsd  -0x88(%rbp),%xmm0
ff
movsd  -0x70(%rbp),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
mov    -0x8(%rbp),%rax
mov    -0x40(%rbp),%rcx
movsd  %xmm0,(%rax,%rcx,8)
movsd  -0x80(%rbp),%xmm0
movsd  %xmm0,-0xa0(%rbp)
ff
movsd  -0x90(%rbp),%xmm2
ff
movsd  -0x88(%rbp),%xmm1
ff
mulsd  -0x98(%rbp),%xmm1
ff
movq   %xmm1,%rax
movabs $0x8000000000000000,%rcx
xor    %rcx,%rax
movq   %rax,%xmm1
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
addsd  -0x80(%rbp),%xmm0
movsd  %xmm0,-0x80(%rbp)
movsd  -0x88(%rbp),%xmm0
ff
movsd  -0x90(%rbp),%xmm2
ff
movsd  -0xa0(%rbp),%xmm1
ff
mulsd  -0x98(%rbp),%xmm1
ff
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
addsd  -0x88(%rbp),%xmm0
ff
movsd  %xmm0,-0x88(%rbp)
ff
mov    -0x20(%rbp),%rax
add    $0x1,%rax
mov    %rax,-0x20(%rbp)
jmp    1255 <realft+0x135>
cmpl   $0x1,-0x14(%rbp)
jne    1552 <realft+0x432>
mov    -0x8(%rbp),%rax
movsd  0x8(%rax),%xmm0
movsd  %xmm0,-0x60(%rbp)
mov    -0x8(%rbp),%rax
addsd  0x10(%rax),%xmm0
mov    -0x8(%rbp),%rax
movsd  %xmm0,0x8(%rax)
movsd  -0x60(%rbp),%xmm0
mov    -0x8(%rbp),%rax
subsd  0x10(%rax),%xmm0
mov    -0x8(%rbp),%rax
movsd  %xmm0,0x10(%rax)
jmp    15b1 <realft+0x491>
movsd  -0x50(%rbp),%xmm0
mov    -0x8(%rbp),%rax
movsd  0x8(%rax),%xmm1
movsd  %xmm1,-0x60(%rbp)
mov    -0x8(%rbp),%rax
addsd  0x10(%rax),%xmm1
mulsd  %xmm1,%xmm0
mov    -0x8(%rbp),%rax
movsd  %xmm0,0x8(%rax)
movsd  -0x50(%rbp),%xmm0
movsd  -0x60(%rbp),%xmm1
mov    -0x8(%rbp),%rax
subsd  0x10(%rax),%xmm1
mulsd  %xmm1,%xmm0
mov    -0x8(%rbp),%rax
movsd  %xmm0,0x10(%rax)
mov    -0x8(%rbp),%rdi
mov    -0x10(%rbp),%rsi
shr    $0x1,%rsi
mov    $0xffffffff,%edx
call   1030 <four1@plt>
add    $0xb0,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<realft>:
push   %rbp
push   %r15
push   %r14
push   %rbx
sub    $0x38,%rsp
mov    %rsi,%rbx
mov    %rsi,%r14
shr    %r14
cvtsi2sd %r14,%xmm0
mov    %edx,%ebp
mov    %rdi,%r15
movsd  0xebb(%rip),%xmm1
divsd  %xmm0,%xmm1
cmp    $0x1,%edx
jne    1172 <realft+0x52>
mov    %r15,%rdi
mov    %r14,%rsi
mov    $0x1,%edx
movapd %xmm1,(%rsp)
call   1030 <four1@plt>
movapd (%rsp),%xmm1
movsd  0xea0(%rip),%xmm0
jmp    1182 <realft+0x62>
xorpd  0xeb6(%rip),%xmm1
movsd  0xe86(%rip),%xmm0
movaps %xmm0,0x20(%rsp)
movapd %xmm1,(%rsp)
movsd  0xe74(%rip),%xmm0
mulsd  %xmm1,%xmm0
call   1040 <sin@plt>
movsd  %xmm0,0x18(%rsp)
movapd (%rsp),%xmm0
call   1040 <sin@plt>
cmp    $0x8,%rbx
movapd 0x20(%rsp),%xmm12
jb     12fe <realft+0x1de>
movsd  0xe51(%rip),%xmm9
movsd  0x18(%rsp),%xmm1
mulsd  %xmm1,%xmm9
mulsd  %xmm1,%xmm9
lea    (%r15,%rbx,8),%rax
add    $0xfffffffffffffff8,%rax
shr    $0x2,%rbx
movsd  0xe35(%rip),%xmm2
addsd  %xmm9,%xmm2
movapd 0xe38(%rip),%xmm1
xorpd  %xmm12,%xmm1
movapd %xmm0,%xmm11
unpcklpd %xmm2,%xmm11
unpcklpd %xmm1,%xmm12
unpcklpd %xmm9,%xmm9
unpcklpd %xmm0,%xmm0
add    $0xffffffffffffffff,%rbx
lea    0x18(%r15),%rcx
movapd 0xe1a(%rip),%xmm8
movapd 0xe01(%rip),%xmm10
nop
movupd (%rcx),%xmm6
movupd (%rax),%xmm5
movapd %xmm6,%xmm7
addpd  %xmm5,%xmm7
subpd  %xmm5,%xmm6
movapd %xmm6,%xmm5
movsd  %xmm7,%xmm5
mulpd  %xmm8,%xmm5
shufpd $0x2,%xmm7,%xmm6
mulpd  %xmm12,%xmm6
movapd %xmm11,%xmm7
xorpd  %xmm10,%xmm7
movapd %xmm11,%xmm2
shufpd $0x1,%xmm7,%xmm2
unpcklpd %xmm11,%xmm7
mulpd  %xmm6,%xmm7
movapd %xmm11,%xmm3
unpcklpd %xmm11,%xmm3
mulpd  %xmm6,%xmm3
shufpd $0x1,%xmm6,%xmm6
movapd %xmm11,%xmm4
unpckhpd %xmm11,%xmm4
movapd %xmm4,%xmm1
mulpd  %xmm6,%xmm1
addpd  %xmm5,%xmm1
addpd  %xmm1,%xmm7
movupd %xmm7,(%rcx)
xorpd  %xmm10,%xmm4
movapd %xmm5,%xmm1
unpckhpd %xmm5,%xmm1
xorpd  %xmm10,%xmm1
shufpd $0x2,%xmm11,%xmm4
unpcklpd %xmm1,%xmm5
mulpd  %xmm6,%xmm4
addpd  %xmm5,%xmm4
addpd  %xmm4,%xmm3
movupd %xmm3,(%rax)
mulpd  %xmm0,%xmm2
movapd %xmm11,%xmm1
mulpd  %xmm9,%xmm1
addpd  %xmm2,%xmm1
addpd  %xmm1,%xmm11
add    $0xfffffffffffffff0,%rax
add    $0x10,%rcx
add    $0xffffffffffffffff,%rbx
jne    1230 <realft+0x110>
movsd  0x8(%r15),%xmm0
movsd  0x10(%r15),%xmm2
movapd %xmm0,%xmm1
addsd  %xmm2,%xmm1
cmp    $0x1,%ebp
jne    1332 <realft+0x212>
movsd  %xmm1,0x8(%r15)
subsd  %xmm2,%xmm0
movsd  %xmm0,0x10(%r15)
add    $0x38,%rsp
pop    %rbx
pop    %r14
pop    %r15
pop    %rbp
ret
subsd  %xmm2,%xmm0
unpcklpd %xmm0,%xmm1
mulpd  0xcfe(%rip),%xmm1
movupd %xmm1,0x8(%r15)
mov    %r15,%rdi
mov    %r14,%rsi
mov    $0xffffffff,%edx
add    $0x38,%rsp
pop    %rbx
pop    %r14
pop    %r15
pop    %rbp
jmp    1030 <four1@plt>

LLVM IR (-O0):
define void @realft(double* %0, i64 %1, i32 %2) {
%4 = alloca double*
%5 = alloca i64
%6 = alloca i32
%7 = alloca i64
%8 = alloca i64
%9 = alloca i64
%10 = alloca i64
%11 = alloca i64
%12 = alloca i64
%13 = alloca double
%14 = alloca double
%15 = alloca double
%16 = alloca double
%17 = alloca double
%18 = alloca double
%19 = alloca double
%20 = alloca double
%21 = alloca double
%22 = alloca double
%23 = alloca double
%24 = alloca double
store double* %0, double** %4
store i64 %1, i64* %5
store i32 %2, i32* %6
store double 5.000000e-01, double* %13
%25 = load i64, i64* %5
%26 = lshr i64 %25, 1
%27 = uitofp i64 %26 to double
%28 = fdiv double 0x400921FB54442D18, %27
store double %28, double* %24
%29 = load i32, i32* %6
%30 = icmp eq i32 %29, 1
br i1 %30, label %31, label %36
31: ; preds = %3
store double -5.000000e-01, double* %14
%32 = load double*, double** %4
%33 = load i64, i64* %5
%34 = lshr i64 %33, 1
%35 = call i32 @four1(double* %32, i64 %34, i32 1)
br label %39
36: ; preds = %3
store double 5.000000e-01, double* %14
%37 = load double, double* %24
%38 = fneg double %37
store double %38, double* %24
br label %39
39: ; preds = %36, %31
%40 = load double, double* %24
%41 = fmul double 5.000000e-01, %40
%42 = call double @sin(double %41)
store double %42, double* %23
%43 = load double, double* %23
%44 = fmul double -2.000000e+00, %43
%45 = load double, double* %23
%46 = fmul double %44, %45
store double %46, double* %21
%47 = load double, double* %24
%48 = call double @sin(double %47)
store double %48, double* %22
%49 = load double, double* %21
%50 = fadd double 1.000000e+00, %49
store double %50, double* %19
%51 = load double, double* %22
store double %51, double* %20
%52 = load i64, i64* %5
%53 = add i64 %52, 3
store i64 %53, i64* %12
store i64 2, i64* %7
br label %54
54: ; preds = %173, %39
%55 = load i64, i64* %7
%56 = load i64, i64* %5
%57 = lshr i64 %56, 2
%58 = icmp ule i64 %55, %57
br i1 %58, label %59, label %176
59: ; preds = %54
%60 = load i64, i64* %12
%61 = load i64, i64* %7
%62 = load i64, i64* %7
%63 = add i64 %61, %62
%64 = sub i64 %63, 1
store i64 %64, i64* %8
%65 = add i64 1, %64
store i64 %65, i64* %9
%66 = sub i64 %60, %65
store i64 %66, i64* %10
%67 = add i64 1, %66
store i64 %67, i64* %11
%68 = load double, double* %13
%69 = load double*, double** %4
%70 = load i64, i64* %8
%71 = getelementptr inbounds double, double* %69, i64 %70
%72 = load double, double* %71
%73 = load double*, double** %4
%74 = load i64, i64* %10
%75 = getelementptr inbounds double, double* %73, i64 %74
%76 = load double, double* %75
%77 = fadd double %72, %76
%78 = fmul double %68, %77
store double %78, double* %15
%79 = load double, double* %13
%80 = load double*, double** %4
%81 = load i64, i64* %9
%82 = getelementptr inbounds double, double* %80, i64 %81
%83 = load double, double* %82
%84 = load double*, double** %4
%85 = load i64, i64* %11
%86 = getelementptr inbounds double, double* %84, i64 %85
%87 = load double, double* %86
%88 = fsub double %83, %87
%89 = fmul double %79, %88
store double %89, double* %16
%90 = load double, double* %14
%91 = fneg double %90
%92 = load double*, double** %4
%93 = load i64, i64* %9
%94 = getelementptr inbounds double, double* %92, i64 %93
%95 = load double, double* %94
%96 = load double*, double** %4
%97 = load i64, i64* %11
%98 = getelementptr inbounds double, double* %96, i64 %97
%99 = load double, double* %98
%100 = fadd double %95, %99
%101 = fmul double %91, %100
store double %101, double* %17
%102 = load double, double* %14
%103 = load double*, double** %4
%104 = load i64, i64* %8
%105 = getelementptr inbounds double, double* %103, i64 %104
%106 = load double, double* %105
%107 = load double*, double** %4
%108 = load i64, i64* %10
%109 = getelementptr inbounds double, double* %107, i64 %108
%110 = load double, double* %109
%111 = fsub double %106, %110
%112 = fmul double %102, %111
store double %112, double* %18
%113 = load double, double* %15
%114 = load double, double* %19
%115 = load double, double* %17
%116 = call double @llvm.fmuladd.f64(double %114, double %115, double %113)
%117 = load double, double* %20
%118 = load double, double* %18
%119 = fneg double %117
%120 = call double @llvm.fmuladd.f64(double %119, double %118, double %116)
%121 = load double*, double** %4
%122 = load i64, i64* %8
%123 = getelementptr inbounds double, double* %121, i64 %122
store double %120, double* %123
%124 = load double, double* %16
%125 = load double, double* %19
%126 = load double, double* %18
%127 = call double @llvm.fmuladd.f64(double %125, double %126, double %124)
%128 = load double, double* %20
%129 = load double, double* %17
%130 = call double @llvm.fmuladd.f64(double %128, double %129, double %127)
%131 = load double*, double** %4
%132 = load i64, i64* %9
%133 = getelementptr inbounds double, double* %131, i64 %132
store double %130, double* %133
%134 = load double, double* %15
%135 = load double, double* %19
%136 = load double, double* %17
%137 = fneg double %135
%138 = call double @llvm.fmuladd.f64(double %137, double %136, double %134)
%139 = load double, double* %20
%140 = load double, double* %18
%141 = call double @llvm.fmuladd.f64(double %139, double %140, double %138)
%142 = load double*, double** %4
%143 = load i64, i64* %10
%144 = getelementptr inbounds double, double* %142, i64 %143
store double %141, double* %144
%145 = load double, double* %16
%146 = fneg double %145
%147 = load double, double* %19
%148 = load double, double* %18
%149 = call double @llvm.fmuladd.f64(double %147, double %148, double %146)
%150 = load double, double* %20
%151 = load double, double* %17
%152 = call double @llvm.fmuladd.f64(double %150, double %151, double %149)
%153 = load double*, double** %4
%154 = load i64, i64* %11
%155 = getelementptr inbounds double, double* %153, i64 %154
store double %152, double* %155
%156 = load double, double* %19
store double %156, double* %23
%157 = load double, double* %21
%158 = load double, double* %20
%159 = load double, double* %22
%160 = fmul double %158, %159
%161 = fneg double %160
%162 = call double @llvm.fmuladd.f64(double %156, double %157, double %161)
%163 = load double, double* %19
%164 = fadd double %162, %163
store double %164, double* %19
%165 = load double, double* %20
%166 = load double, double* %21
%167 = load double, double* %23
%168 = load double, double* %22
%169 = fmul double %167, %168
%170 = call double @llvm.fmuladd.f64(double %165, double %166, double %169)
%171 = load double, double* %20
%172 = fadd double %170, %171
store double %172, double* %20
br label %173
173: ; preds = %59
%174 = load i64, i64* %7
%175 = add i64 %174, 1
store i64 %175, i64* %7
br label %54
176: ; preds = %54
%177 = load i32, i32* %6
%178 = icmp eq i32 %177, 1
br i1 %178, label %179, label %196
179: ; preds = %176
%180 = load double*, double** %4
%181 = getelementptr inbounds double, double* %180, i64 1
%182 = load double, double* %181
store double %182, double* %15
%183 = load double*, double** %4
%184 = getelementptr inbounds double, double* %183, i64 2
%185 = load double, double* %184
%186 = fadd double %182, %185
%187 = load double*, double** %4
%188 = getelementptr inbounds double, double* %187, i64 1
store double %186, double* %188
%189 = load double, double* %15
%190 = load double*, double** %4
%191 = getelementptr inbounds double, double* %190, i64 2
%192 = load double, double* %191
%193 = fsub double %189, %192
%194 = load double*, double** %4
%195 = getelementptr inbounds double, double* %194, i64 2
store double %193, double* %195
br label %221
196: ; preds = %176
%197 = load double, double* %13
%198 = load double*, double** %4
%199 = getelementptr inbounds double, double* %198, i64 1
%200 = load double, double* %199
store double %200, double* %15
%201 = load double*, double** %4
%202 = getelementptr inbounds double, double* %201, i64 2
%203 = load double, double* %202
%204 = fadd double %200, %203
%205 = fmul double %197, %204
%206 = load double*, double** %4
%207 = getelementptr inbounds double, double* %206, i64 1
store double %205, double* %207
%208 = load double, double* %13
%209 = load double, double* %15
%210 = load double*, double** %4
%211 = getelementptr inbounds double, double* %210, i64 2
%212 = load double, double* %211
%213 = fsub double %209, %212
%214 = fmul double %208, %213
%215 = load double*, double** %4
%216 = getelementptr inbounds double, double* %215, i64 2
store double %214, double* %216
%217 = load double*, double** %4
%218 = load i64, i64* %5
%219 = lshr i64 %218, 1
%220 = call i32 @four1(double* %217, i64 %219, i32 -1)
br label %221
221: ; preds = %196, %179
ret void
}

LLVM IR (-O2):
define void @realft(double* %0, i64 %1, i32 %2) {
%4 = lshr i64 %1, 1
%5 = uitofp i64 %4 to double
%6 = fdiv double 0x400921FB54442D18, %5
%7 = icmp eq i32 %2, 1
br i1 %7, label %8, label %10
8: ; preds = %3
%9 = tail call i32 @four1(double* %0, i64 %4, i32 1)
br label %12
10: ; preds = %3
%11 = fneg double %6
br label %12
12: ; preds = %10, %8
%13 = phi double [ -5.000000e-01, %8 ], [ 5.000000e-01, %10 ]
%14 = phi double [ %6, %8 ], [ %11, %10 ]
%15 = fmul double %14, 5.000000e-01
%16 = tail call double @sin(double %15)
%17 = fmul double %16, -2.000000e+00
%18 = fmul double %16, %17
%19 = tail call double @sin(double %14)
%20 = add i64 %1, 3
%21 = icmp ult i64 %1, 8
br i1 %21, label %78, label %22
22: ; preds = %12
%23 = lshr i64 %1, 2
%24 = fadd double %18, 1.000000e+00
%25 = fneg double %13
%26 = insertelement <2 x double> poison, double %19, i64 0
%27 = insertelement <2 x double> %26, double %24, i64 1
%28 = insertelement <2 x double> poison, double %13, i64 0
%29 = insertelement <2 x double> %28, double %25, i64 1
%30 = insertelement <2 x double> poison, double %18, i64 0
%31 = shufflevector <2 x double> %30, <2 x double> poison, <2 x i32> zeroinitializer
%32 = shufflevector <2 x double> %26, <2 x double> poison, <2 x i32> zeroinitializer
br label %33
33: ; preds = %22, %33
%34 = phi i64 [ 2, %22 ], [ %76, %33 ]
%35 = phi <2 x double> [ %27, %22 ], [ %75, %33 ]
%36 = shl nuw i64 %34, 1
%37 = add nsw i64 %36, -1
%38 = sub i64 %20, %36
%39 = getelementptr inbounds double, double* %0, i64 %37
%40 = getelementptr inbounds double, double* %0, i64 %38
%41 = bitcast double* %39 to <2 x double>*
%42 = load <2 x double>, <2 x double>* %41
%43 = bitcast double* %40 to <2 x double>*
%44 = load <2 x double>, <2 x double>* %43
%45 = fadd <2 x double> %42, %44
%46 = fsub <2 x double> %42, %44
%47 = shufflevector <2 x double> %45, <2 x double> %46, <2 x i32> <i32 0, i32 3>
%48 = fmul <2 x double> %47, <double 5.000000e-01, double 5.000000e-01>
%49 = shufflevector <2 x double> %46, <2 x double> %45, <2 x i32> <i32 0, i32 3>
%50 = fmul <2 x double> %29, %49
%51 = extractelement <2 x double> %35, i64 0
%52 = fneg double %51
%53 = shufflevector <2 x double> %50, <2 x double> poison, <2 x i32> <i32 1, i32 0>
%54 = extractelement <2 x double> %35, i64 1
%55 = shufflevector <2 x double> %35, <2 x double> undef, <2 x i32> <i32 1, i32 undef>
%56 = shufflevector <2 x double> %35, <2 x double> poison, <2 x i32> <i32 1, i32 1>
%57 = call <2 x double> @llvm.fmuladd.v2f64(<2 x double> %56, <2 x double> %53, <2 x double> %48)
%58 = insertelement <2 x double> poison, double %52, i64 0
%59 = shufflevector <2 x double> %58, <2 x double> %35, <2 x i32> <i32 0, i32 2>
%60 = call <2 x double> @llvm.fmuladd.v2f64(<2 x double> %59, <2 x double> %50, <2 x double> %57)
%61 = bitcast double* %39 to <2 x double>*
store <2 x double> %60, <2 x double>* %61
%62 = fneg double %54
%63 = extractelement <2 x double> %48, i64 1
%64 = fneg double %63
%65 = insertelement <2 x double> %35, double %62, i64 0
%66 = shufflevector <2 x double> %50, <2 x double> undef, <2 x i32> <i32 1, i32 0>
%67 = insertelement <2 x double> %48, double %64, i64 1
%68 = call <2 x double> @llvm.fmuladd.v2f64(<2 x double> %65, <2 x double> %66, <2 x double> %67)
%69 = shufflevector <2 x double> %35, <2 x double> undef, <2 x i32> zeroinitializer
%70 = call <2 x double> @llvm.fmuladd.v2f64(<2 x double> %69, <2 x double> %50, <2 x double> %68)
%71 = bitcast double* %40 to <2 x double>*
store <2 x double> %70, <2 x double>* %71
%72 = insertelement <2 x double> %55, double %52, i64 1
%73 = fmul <2 x double> %32, %72
%74 = call <2 x double> @llvm.fmuladd.v2f64(<2 x double> %35, <2 x double> %31, <2 x double> %73)
%75 = fadd <2 x double> %35, %74
%76 = add nuw nsw i64 %34, 1
%77 = icmp eq i64 %34, %23
br i1 %77, label %78, label %33
78: ; preds = %33, %12
%79 = getelementptr inbounds double, double* %0, i64 1
%80 = load double, double* %79
%81 = getelementptr inbounds double, double* %0, i64 2
%82 = load double, double* %81
%83 = fadd double %80, %82
br i1 %7, label %84, label %86
84: ; preds = %78
store double %83, double* %79
%85 = fsub double %80, %82
store double %85, double* %81
br label %93
86: ; preds = %78
%87 = fsub double %80, %82
%88 = insertelement <2 x double> poison, double %83, i64 0
%89 = insertelement <2 x double> %88, double %87, i64 1
%90 = fmul <2 x double> %89, <double 5.000000e-01, double 5.000000e-01>
%91 = bitcast double* %79 to <2 x double>*
store <2 x double> %90, <2 x double>* %91
%92 = tail call i32 @four1(double* %0, i64 %4, i32 -1)
br label %93
93: ; preds = %86, %84
ret void
}