#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(char *buffer) {
  int x = strlen(buffer) - 1;
  do {
    x--;
  } while (x > 0 && isspace(buffer[x]));
  buffer[x + 1] = '\0';
}


x86 assembly (clang, -O0):
<trim>:
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)
mov    -0xc(%rbp),%eax
add    $0xffffffff,%eax
mov    %eax,-0xc(%rbp)
xor    %eax,%eax
cmpl   $0x0,-0xc(%rbp)
mov    %al,-0xd(%rbp)
jle    116e <trim+0x4e>
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    113b <trim+0x1b>
mov    -0x8(%rbp),%rax
mov    -0xc(%rbp),%ecx
add    $0x1,%ecx
movslq %ecx,%rcx
movb   $0x0,(%rax,%rcx,1)
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<trim>:
push   %rbp
push   %r15
push   %r14
push   %rbx
push   %rax
mov    %rdi,%r14
call   1030 <strlen@plt>
mov    %eax,%ebp
lea    -0x1(%rbp),%eax
test   %eax,%eax
mov    $0x1,%r15d
cmovle %eax,%r15d
mov    %ebp,%ebx
add    $0xfffffffe,%ebx
add    %r14,%rbx
nopl   0x0(%rax,%rax,1)
add    $0xffffffff,%ebp
cmp    $0x2,%ebp
jl     116b <trim+0x4b>
movsbl (%rbx),%edi
call   1040 <isspace@plt>
add    $0xffffffffffffffff,%rbx
test   %rax,%rax
jne    1150 <trim+0x30>
jmp    116e <trim+0x4e>
mov    %r15d,%ebp
movslq %ebp,%rax
movb   $0x0,(%r14,%rax,1)
add    $0x8,%rsp
pop    %rbx
pop    %r14
pop    %r15
pop    %rbp
ret

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

LLVM IR (-O2):
define void @trim(i8* %0) {
%2 = tail call i32 @strlen(i8* %0)
%3 = add i32 %2, -1
%4 = zext i32 %3 to i64
%5 = call i32 @llvm.smin.i32(i32 %3, i32 1)
br label %6
6: ; preds = %11, %1
%7 = phi i64 [ %8, %11 ], [ %4, %1 ]
%8 = add nsw i64 %7, -1
%9 = trunc i64 %7 to i32
%10 = icmp sgt i32 %9, 1
br i1 %10, label %11, label %19
11: ; preds = %6
%12 = and i64 %8, 4294967295
%13 = getelementptr inbounds i8, i8* %0, i64 %12
%14 = load i8, i8* %13
%15 = tail call i64 @isspace(i8 signext %14)
%16 = icmp eq i64 %15, 0
br i1 %16, label %17, label %6
17: ; preds = %11
%18 = trunc i64 %7 to i32
br label %19
19: ; preds = %6, %17
%20 = phi i32 [ %18, %17 ], [ %5, %6 ]
%21 = sext i32 %20 to i64
%22 = getelementptr inbounds i8, i8* %0, i64 %21
store i8 0, i8* %22
ret void
}