#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 */
scalar_t__ isspace(char);
int strlen(char *);
char *rtrim2(char *str) {
  int i = strlen(str) - 1;
  while (i >= 0 && isspace(str[i]))
    --i;
  str[i + 1] = '\0';
  return str;
}


x86 assembly (clang, -O0):
<rtrim2>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
mov    %rdi,-0x8(%rbp)
mov    -0x8(%rbp),%rdi
call   1030 <strlen@plt>
sub    $0x1,%eax
mov    %eax,-0xc(%rbp)
xor    %eax,%eax
cmpl   $0x0,-0xc(%rbp)
mov    %al,-0xd(%rbp)
jl     1165 <rtrim2+0x45>
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
movsbl (%rax,%rcx,1),%edi
call   1040 <isspace@plt>
cmp    $0x0,%rax
setne  %al
mov    %al,-0xd(%rbp)
mov    -0xd(%rbp),%al
test   $0x1,%al
jne    1175 <rtrim2+0x55>
jmp    1183 <rtrim2+0x63>
mov    -0xc(%rbp),%eax
add    $0xffffffff,%eax
mov    %eax,-0xc(%rbp)
jmp    113b <rtrim2+0x1b>
mov    -0x8(%rbp),%rax
mov    -0xc(%rbp),%ecx
add    $0x1,%ecx
movslq %ecx,%rcx
movb   $0x0,(%rax,%rcx,1)
mov    -0x8(%rbp),%rax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<rtrim2>:
push   %rbp
push   %r14
push   %rbx
mov    %rdi,%r14
call   1030 <strlen@plt>
mov    %eax,%ebx
xor    %ebp,%ebp
test   %eax,%eax
cmovs  %eax,%ebp
cs nopw 0x0(%rax,%rax,1)
nop
test   %ebx,%ebx
jle    115d <rtrim2+0x3d>
movsbl -0x1(%r14,%rbx,1),%edi
call   1040 <isspace@plt>
add    $0xffffffffffffffff,%rbx
test   %rax,%rax
jne    1140 <rtrim2+0x20>
add    $0x1,%ebx
mov    %ebx,%ebp
movslq %ebp,%rax
movb   $0x0,(%r14,%rax,1)
mov    %r14,%rax
pop    %rbx
pop    %r14
pop    %rbp
ret

LLVM IR (-O0):
define i8* @rtrim2(i8* %0) {
%2 = alloca i8*
%3 = alloca i32
store i8* %0, i8** %2
%4 = load i8*, i8** %2
%5 = call i32 @strlen(i8* %4)
%6 = sub nsw i32 %5, 1
store i32 %6, i32* %3
br label %7
7: ; preds = %20, %1
%8 = load i32, i32* %3
%9 = icmp sge i32 %8, 0
br i1 %9, label %10, label %18
10: ; preds = %7
%11 = load i8*, i8** %2
%12 = load i32, i32* %3
%13 = sext i32 %12 to i64
%14 = getelementptr inbounds i8, i8* %11, i64 %13
%15 = load i8, i8* %14
%16 = call i64 @isspace(i8 signext %15)
%17 = icmp ne i64 %16, 0
br label %18
18: ; preds = %10, %7
%19 = phi i1 [ false, %7 ], [ %17, %10 ]
br i1 %19, label %20, label %23
20: ; preds = %18
%21 = load i32, i32* %3
%22 = add nsw i32 %21, -1
store i32 %22, i32* %3
br label %7
23: ; preds = %18
%24 = load i8*, i8** %2
%25 = load i32, i32* %3
%26 = add nsw i32 %25, 1
%27 = sext i32 %26 to i64
%28 = getelementptr inbounds i8, i8* %24, i64 %27
store i8 0, i8* %28
%29 = load i8*, i8** %2
ret i8* %29
}

LLVM IR (-O2):
define i8* @rtrim2(i8* returned %0) {
%2 = tail call i32 @strlen(i8* %0)
%3 = zext i32 %2 to i64
%4 = call i32 @llvm.smin.i32(i32 %2, i32 0)
br label %5
5: ; preds = %10, %1
%6 = phi i64 [ %7, %10 ], [ %3, %1 ]
%7 = add nsw i64 %6, -1
%8 = trunc i64 %6 to i32
%9 = icmp sgt i32 %8, 0
br i1 %9, label %10, label %17
10: ; preds = %5
%11 = getelementptr inbounds i8, i8* %0, i64 %7
%12 = load i8, i8* %11
%13 = tail call i64 @isspace(i8 signext %12)
%14 = icmp eq i64 %13, 0
br i1 %14, label %15, label %5
15: ; preds = %10
%16 = trunc i64 %6 to i32
br label %17
17: ; preds = %5, %15
%18 = phi i32 [ %16, %15 ], [ %4, %5 ]
%19 = sext i32 %18 to i64
%20 = getelementptr inbounds i8, i8* %0, i64 %19
store i8 0, i8* %20
ret i8* %0
}