int main() {
  float fahr, celcius;
  int lower, upper, step;
  lower = 0;
  upper = 300;
  step = 20;
  celcius = lower;
  printf("%s%s%s\n", "celcius", "  ", "fahrenheit");
  while (celcius <= upper) {
    fahr = ((9.0 / 5.0) * celcius) + 32.0;
    printf("%7.0f%s%10.1f\n", celcius, "  ", fahr);
    celcius = celcius + step;
  }
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
movl   $0x0,-0x4(%rbp)
movl   $0x0,-0x10(%rbp)
movl   $0x12c,-0x14(%rbp)
movl   $0x14,-0x18(%rbp)
cvtsi2ssl -0x10(%rbp),%xmm0
movss  %xmm0,-0xc(%rbp)
lea    0xecb(%rip),%rdi
lea    0xecc(%rip),%rsi
lea    0xecd(%rip),%rdx
lea    0xec9(%rip),%rcx
mov    $0x0,%al
call   1030 <printf@plt>
movss  -0xc(%rbp),%xmm1
cvtsi2ssl -0x14(%rbp),%xmm0
ucomiss %xmm1,%xmm0
jb     11dd <main+0xcd>
movss  -0xc(%rbp),%xmm0
cvtss2sd %xmm0,%xmm0
movsd  0xe7b(%rip),%xmm1
mulsd  %xmm1,%xmm0
movsd  0xe77(%rip),%xmm1
addsd  %xmm1,%xmm0
cvtsd2ss %xmm0,%xmm0
movss  %xmm0,-0x8(%rbp)
movss  -0xc(%rbp),%xmm0
cvtss2sd %xmm0,%xmm0
movss  -0x8(%rbp),%xmm1
cvtss2sd %xmm1,%xmm1
lea    0xe77(%rip),%rdi
lea    0xe62(%rip),%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movss  -0xc(%rbp),%xmm0
cvtsi2ssl -0x18(%rbp),%xmm1
addss  %xmm1,%xmm0
movss  %xmm0,-0xc(%rbp)
jmp    1161 <main+0x51>
mov    -0x4(%rbp),%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %r14
push   %rbx
push   %rax
lea    0xfd5(%rip),%rdi
lea    0xfd6(%rip),%rsi
lea    0xfd7(%rip),%r14
lea    0xfd3(%rip),%rcx
mov    %r14,%rdx
xor    %eax,%eax
call   1030 <printf@plt>
lea    0xfcd(%rip),%rbx
movsd  0xeb7(%rip),%xmm1
xorps  %xmm0,%xmm0
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xea7(%rip),%xmm0
movsd  0xea7(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xe9a(%rip),%xmm0
movsd  0xe9a(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xe8d(%rip),%xmm0
movsd  0xe8d(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xe80(%rip),%xmm0
movsd  0xe80(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xe73(%rip),%xmm0
movsd  0xe73(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xe66(%rip),%xmm0
movsd  0xe66(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xe59(%rip),%xmm1
mov    %rbx,%rdi
movsd  0xe16(%rip),%xmm0
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xe44(%rip),%xmm0
movsd  0xe44(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xe37(%rip),%xmm0
movsd  0xe37(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xe2a(%rip),%xmm0
movsd  0xe2a(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xe1d(%rip),%xmm0
movsd  0xe1d(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xe10(%rip),%xmm0
movsd  0xe10(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xe03(%rip),%xmm0
movsd  0xe03(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xdf6(%rip),%xmm0
movsd  0xdf6(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
movsd  0xde9(%rip),%xmm0
movsd  0xde9(%rip),%xmm1
mov    %rbx,%rdi
mov    %r14,%rsi
mov    $0x2,%al
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x8,%rsp
pop    %rbx
pop    %r14
ret

LLVM IR (-O0):
@.str = [8 x i8] c"%s%s%s\0A\00"
@.str.1 = [8 x i8] c"celcius\00"
@.str.2 = [3 x i8] c" \00"
@.str.3 = [11 x i8] c"fahrenheit\00"
@.str.4 = [15 x i8] c"%7.0f%s%10.1f\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca float
%3 = alloca float
%4 = alloca i32
%5 = alloca i32
%6 = alloca i32
store i32 0, i32* %1
store i32 0, i32* %4
store i32 300, i32* %5
store i32 20, i32* %6
%7 = load i32, i32* %4
%8 = sitofp i32 %7 to float
store float %8, float* %3
%9 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str, i64 0, i64 0), i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.1, i64 0, i64 0), i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str.3, i64 0, i64 0))
br label %10
10: ; preds = %15, %0
%11 = load float, float* %3
%12 = load i32, i32* %5
%13 = sitofp i32 %12 to float
%14 = fcmp ole float %11, %13
br i1 %14, label %15, label %29
15: ; preds = %10
%16 = load float, float* %3
%17 = fpext float %16 to double
%18 = call double @llvm.fmuladd.f64(double 1.800000e+00, double %17, double 3.200000e+01)
%19 = fptrunc double %18 to float
store float %19, float* %2
%20 = load float, float* %3
%21 = fpext float %20 to double
%22 = load float, float* %2
%23 = fpext float %22 to double
%24 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double %21, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double %23)
%25 = load float, float* %3
%26 = load i32, i32* %6
%27 = sitofp i32 %26 to float
%28 = fadd float %25, %27
store float %28, float* %3
br label %10
29: ; preds = %10
%30 = load i32, i32* %1
ret i32 %30
}

LLVM IR (-O2):
@.str = [8 x i8] c"%s%s%s\0A\00"
@.str.1 = [8 x i8] c"celcius\00"
@.str.2 = [3 x i8] c" \00"
@.str.3 = [11 x i8] c"fahrenheit\00"
@.str.4 = [15 x i8] c"%7.0f%s%10.1f\0A\00"
define i32 @main() {
%1 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([8 x i8], [8 x i8]* @.str, i64 0, i64 0), i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str.1, i64 0, i64 0), i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str.3, i64 0, i64 0))
%2 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 0.000000e+00, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 3.200000e+01)
%3 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 2.000000e+01, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 6.800000e+01)
%4 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 4.000000e+01, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 1.040000e+02)
%5 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 6.000000e+01, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 1.400000e+02)
%6 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 8.000000e+01, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 1.760000e+02)
%7 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 1.000000e+02, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 2.120000e+02)
%8 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 1.200000e+02, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 2.480000e+02)
%9 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 1.400000e+02, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 2.840000e+02)
%10 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 1.600000e+02, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 3.200000e+02)
%11 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 1.800000e+02, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 3.560000e+02)
%12 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 2.000000e+02, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 3.920000e+02)
%13 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 2.200000e+02, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 4.280000e+02)
%14 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 2.400000e+02, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 4.640000e+02)
%15 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 2.600000e+02, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 5.000000e+02)
%16 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 2.800000e+02, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 5.360000e+02)
%17 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), double 3.000000e+02, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str.2, i64 0, i64 0), double 5.720000e+02)
ret i32 0
}