#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 trim_trailing_whitespace(char *s) {
  int i;
  char c;
  i = strlen(s);
  while (--i >= 0) {
    c = s[i];
    if (isspace(c))
      s[i] = '\0';
    else
      break;
  }
}


x86 assembly (clang, -O0):
<trim_trailing_whitespace>:
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
add    $0xffffffff,%eax
mov    %eax,-0xc(%rbp)
cmp    $0x0,%eax
jl     1186 <trim_trailing_whitespace+0x66>
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
mov    (%rax,%rcx,1),%al
mov    %al,-0xd(%rbp)
movsbl -0xd(%rbp),%edi
call   1040 <isspace@plt>
cmp    $0x0,%rax
je     117c <trim_trailing_whitespace+0x5c>
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
movb   $0x0,(%rax,%rcx,1)
jmp    1181 <trim_trailing_whitespace+0x61>
jmp    1186 <trim_trailing_whitespace+0x66>
jmp    1138 <trim_trailing_whitespace+0x18>
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<trim_trailing_whitespace>:
push   %r15
push   %r14
push   %rbx
mov    %rdi,%r14
call   1030 <strlen@plt>
test   %eax,%eax
jle    1162 <trim_trailing_whitespace+0x42>
mov    %eax,%ebx
add    $0x1,%rbx
nopw   0x0(%rax,%rax,1)
lea    -0x2(%rbx),%r15d
movsbl (%r14,%r15,1),%edi
call   1040 <isspace@plt>
test   %rax,%rax
je     1162 <trim_trailing_whitespace+0x42>
movb   $0x0,(%r14,%r15,1)
add    $0xffffffffffffffff,%rbx
cmp    $0x1,%rbx
ja     1140 <trim_trailing_whitespace+0x20>
pop    %rbx
pop    %r14
pop    %r15
ret

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

LLVM IR (-O2):
define void @trim_trailing_whitespace(i8* %0) {
%2 = tail call i32 @strlen(i8* %0)
%3 = icmp sgt i32 %2, 0
br i1 %3, label %4, label %16
4: ; preds = %1
%5 = zext i32 %2 to i64
br label %6
6: ; preds = %4, %14
%7 = phi i64 [ %5, %4 ], [ %8, %14 ]
%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 = tail call i64 @isspace(i8 signext %11)
%13 = icmp eq i64 %12, 0
br i1 %13, label %16, label %14
14: ; preds = %6
store i8 0, i8* %10
%15 = icmp ugt i64 %7, 1
br i1 %15, label %6, label %16
16: ; preds = %14, %6, %1
ret void
}