#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 rm_blank_tails(char *s) {
  char *t = s + strlen(s);
  while (t-- > s && isspace(*t))
    *t = '\0';
}


x86 assembly (clang, -O0):
<rm_blank_tails>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    -0x8(%rbp),%rax
mov    %rax,-0x18(%rbp)
mov    -0x8(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,%ecx
mov    -0x18(%rbp),%rax
movslq %ecx,%rcx
add    %rcx,%rax
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rcx
mov    %rcx,%rax
add    $0xffffffffffffffff,%rax
mov    %rax,-0x10(%rbp)
xor    %eax,%eax
cmp    -0x8(%rbp),%rcx
mov    %al,-0x19(%rbp)
jbe    1181 <rm_blank_tails+0x61>
mov    -0x10(%rbp),%rax
movsbl (%rax),%edi
call   1040 <isspace@plt>
cmp    $0x0,%rax
setne  %al
mov    %al,-0x19(%rbp)
mov    -0x19(%rbp),%al
test   $0x1,%al
jne    1191 <rm_blank_tails+0x71>
jmp    119d <rm_blank_tails+0x7d>
mov    -0x10(%rbp),%rax
movb   $0x0,(%rax)
jmp    114d <rm_blank_tails+0x2d>
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<rm_blank_tails>:
push   %r14
push   %rbx
push   %rax
mov    %rdi,%r14
call   1030 <strlen@plt>
test   %eax,%eax
jle    115b <rm_blank_tails+0x3b>
mov    %eax,%ebx
add    %r14,%rbx
cs nopw 0x0(%rax,%rax,1)
nop
movsbl -0x1(%rbx),%edi
call   1040 <isspace@plt>
test   %rax,%rax
je     115b <rm_blank_tails+0x3b>
movb   $0x0,-0x1(%rbx)
add    $0xffffffffffffffff,%rbx
cmp    %r14,%rbx
ja     1140 <rm_blank_tails+0x20>
add    $0x8,%rsp
pop    %rbx
pop    %r14
ret

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

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