#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 strlen(char *);
void trim_trailing_space(char *s) {
  int i, n = strlen(s);
  for (i = n - 1; i > 0; i--) {
    if (s[i] == ' ') {
      s[i] = '\0';
    } else {
      break;
    }
  }
}


x86 assembly (clang, -O0):
<trim_trailing_space>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
mov    %rdi,-0x8(%rbp)
mov    -0x8(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,-0x10(%rbp)
mov    -0x10(%rbp),%eax
sub    $0x1,%eax
mov    %eax,-0xc(%rbp)
cmpl   $0x0,-0xc(%rbp)
jle    1179 <trim_trailing_space+0x69>
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
movsbl (%rax,%rcx,1),%eax
cmp    $0x20,%eax
jne    1161 <trim_trailing_space+0x51>
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
movb   $0x0,(%rax,%rcx,1)
jmp    1166 <trim_trailing_space+0x56>
jmp    1179 <trim_trailing_space+0x69>
jmp    116b <trim_trailing_space+0x5b>
mov    -0xc(%rbp),%eax
add    $0xffffffff,%eax
mov    %eax,-0xc(%rbp)
jmp    1131 <trim_trailing_space+0x21>
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<trim_trailing_space>:
push   %rbx
mov    %rdi,%rbx
call   1030 <strlen@plt>
cmp    $0x2,%eax
jl     1147 <trim_trailing_space+0x37>
mov    %eax,%eax
add    $0x1,%rax
cs nopw 0x0(%rax,%rax,1)
xchg   %ax,%ax
lea    -0x2(%rax),%ecx
cmpb   $0x20,(%rbx,%rcx,1)
jne    1147 <trim_trailing_space+0x37>
movb   $0x0,(%rbx,%rcx,1)
add    $0xffffffffffffffff,%rax
cmp    $0x2,%rax
ja     1130 <trim_trailing_space+0x20>
pop    %rbx
ret

LLVM IR (-O0):
define void @trim_trailing_space(i8* %0) {
%2 = alloca i8*
%3 = alloca i32
%4 = alloca i32
store i8* %0, i8** %2
%5 = load i8*, i8** %2
%6 = call i32 @strlen(i8* %5)
store i32 %6, i32* %4
%7 = load i32, i32* %4
%8 = sub nsw i32 %7, 1
store i32 %8, i32* %3
br label %9
9: ; preds = %27, %1
%10 = load i32, i32* %3
%11 = icmp sgt i32 %10, 0
br i1 %11, label %12, label %30
12: ; preds = %9
%13 = load i8*, i8** %2
%14 = load i32, i32* %3
%15 = sext i32 %14 to i64
%16 = getelementptr inbounds i8, i8* %13, i64 %15
%17 = load i8, i8* %16
%18 = sext i8 %17 to i32
%19 = icmp eq i32 %18, 32
br i1 %19, label %20, label %25
20: ; preds = %12
%21 = load i8*, i8** %2
%22 = load i32, i32* %3
%23 = sext i32 %22 to i64
%24 = getelementptr inbounds i8, i8* %21, i64 %23
store i8 0, i8* %24
br label %26
25: ; preds = %12
br label %30
26: ; preds = %20
br label %27
27: ; preds = %26
%28 = load i32, i32* %3
%29 = add nsw i32 %28, -1
store i32 %29, i32* %3
br label %9
30: ; preds = %25, %9
ret void
}

LLVM IR (-O2):
define void @trim_trailing_space(i8* %0) {
%2 = tail call i32 @strlen(i8* %0)
%3 = icmp sgt i32 %2, 1
br i1 %3, label %4, label %15
4: ; preds = %1
%5 = zext i32 %2 to i64
br label %6
6: ; preds = %4, %13
%7 = phi i64 [ %5, %4 ], [ %8, %13 ]
%8 = add nsw i64 %7, -1
%9 = and i64 %8, 4294967295
%10 = getelementptr inbounds i8, i8* %0, i64 %9
%11 = load i8, i8* %10
%12 = icmp eq i8 %11, 32
br i1 %12, label %13, label %15
13: ; preds = %6
store i8 0, i8* %10
%14 = icmp ugt i64 %7, 2
br i1 %14, label %6, label %15
15: ; preds = %13, %6, %1
ret void
}