#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 *);
void striptrail(char *str) {
  int len;
  len = strlen(str);
  while (len--) {
    if (isspace(str[len]))
      str[len] = 0;
    else
      break;
  }
}


x86 assembly (clang, -O0):
<striptrail>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
mov    %rdi,-0x8(%rbp)
mov    -0x8(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,-0xc(%rbp)
mov    -0xc(%rbp),%eax
mov    %eax,%ecx
add    $0xffffffff,%ecx
mov    %ecx,-0xc(%rbp)
cmp    $0x0,%eax
je     1182 <striptrail+0x62>
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
movsbl (%rax,%rcx,1),%edi
call   1040 <isspace@plt>
cmp    $0x0,%rax
je     1178 <striptrail+0x58>
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
movb   $0x0,(%rax,%rcx,1)
jmp    117d <striptrail+0x5d>
jmp    1182 <striptrail+0x62>
jmp    1138 <striptrail+0x18>
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<striptrail>:
push   %r15
push   %r14
push   %rbx
mov    %rdi,%r14
call   1030 <strlen@plt>
test   %eax,%eax
je     116d <striptrail+0x4d>
mov    %eax,%r15d
cltq
add    %rax,%r14
add    $0xffffffffffffffff,%r14
neg    %r15d
xor    %ebx,%ebx
cs nopw 0x0(%rax,%rax,1)
nopl   0x0(%rax)
movsbl (%r14,%rbx,1),%edi
call   1040 <isspace@plt>
test   %rax,%rax
je     116d <striptrail+0x4d>
movb   $0x0,(%r14,%rbx,1)
add    $0xffffffffffffffff,%rbx
cmp    %ebx,%r15d
jne    1150 <striptrail+0x30>
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
define void @striptrail(i8* %0) {
%2 = alloca i8*
%3 = alloca i32
store i8* %0, i8** %2
%4 = load i8*, i8** %2
%5 = call i32 @strlen(i8* %4)
store i32 %5, i32* %3
br label %6
6: ; preds = %24, %1
%7 = load i32, i32* %3
%8 = add nsw i32 %7, -1
store i32 %8, i32* %3
%9 = icmp ne i32 %7, 0
br i1 %9, label %10, label %25
10: ; preds = %6
%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 i1 %17, label %18, label %23
18: ; preds = %10
%19 = load i8*, i8** %2
%20 = load i32, i32* %3
%21 = sext i32 %20 to i64
%22 = getelementptr inbounds i8, i8* %19, i64 %21
store i8 0, i8* %22
br label %24
23: ; preds = %10
br label %25
24: ; preds = %18
br label %6
25: ; preds = %23, %6
ret void
}

LLVM IR (-O2):
define void @striptrail(i8* %0) {
%2 = tail call i32 @strlen(i8* %0)
%3 = icmp eq i32 %2, 0
br i1 %3, label %16, label %4
4: ; preds = %1
%5 = sext 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 = getelementptr inbounds i8, i8* %0, i64 %8
%10 = load i8, i8* %9
%11 = tail call i64 @isspace(i8 signext %10)
%12 = icmp eq i64 %11, 0
br i1 %12, label %16, label %13
13: ; preds = %6
store i8 0, i8* %9
%14 = trunc i64 %8 to i32
%15 = icmp eq i32 %14, 0
br i1 %15, label %16, label %6
16: ; preds = %13, %6, %1
ret void
}