#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__ is_char(char const);
int char_len(const char *s, int sz) {
  int l;
  for (l = 0; sz > 0 && is_char(*s); l++, sz--)
    s++;
  return l;
}


x86 assembly (clang, -O0):
<char_len>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    %esi,-0xc(%rbp)
movl   $0x0,-0x10(%rbp)
xor    %eax,%eax
cmpl   $0x0,-0xc(%rbp)
mov    %al,-0x11(%rbp)
jle    114b <char_len+0x3b>
mov    -0x8(%rbp),%rax
movsbl (%rax),%edi
call   1030 <is_char@plt>
cmp    $0x0,%rax
setne  %al
mov    %al,-0x11(%rbp)
mov    -0x11(%rbp),%al
test   $0x1,%al
jne    115b <char_len+0x4b>
jmp    117e <char_len+0x6e>
mov    -0x8(%rbp),%rax
add    $0x1,%rax
mov    %rax,-0x8(%rbp)
mov    -0x10(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x10(%rbp)
mov    -0xc(%rbp),%eax
add    $0xffffffff,%eax
mov    %eax,-0xc(%rbp)
jmp    1126 <char_len+0x16>
mov    -0x10(%rbp),%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<char_len>:
push   %r15
push   %r14
push   %rbx
test   %esi,%esi
jle    114a <char_len+0x3a>
mov    %rdi,%r15
mov    %esi,%r14d
xor    %ebx,%ebx
cs nopw 0x0(%rax,%rax,1)
nopl   0x0(%rax,%rax,1)
movsbl (%r15,%rbx,1),%edi
call   1030 <is_char@plt>
test   %rax,%rax
je     114f <char_len+0x3f>
add    $0x1,%rbx
cmp    %ebx,%r14d
jne    1130 <char_len+0x20>
jmp    1152 <char_len+0x42>
xor    %r14d,%r14d
jmp    1152 <char_len+0x42>
mov    %ebx,%r14d
mov    %r14d,%eax
pop    %rbx
pop    %r14
pop    %r15
ret

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

LLVM IR (-O2):
define i32 @char_len(i8* nocapture %0, i32 %1) {
%3 = icmp sgt i32 %1, 0
br i1 %3, label %4, label %14
4: ; preds = %2, %10
%5 = phi i32 [ %12, %10 ], [ 0, %2 ]
%6 = phi i8* [ %11, %10 ], [ %0, %2 ]
%7 = load i8, i8* %6
%8 = tail call i64 @is_char(i8 signext %7)
%9 = icmp eq i64 %8, 0
br i1 %9, label %14, label %10
10: ; preds = %4
%11 = getelementptr inbounds i8, i8* %6, i64 1
%12 = add nuw nsw i32 %5, 1
%13 = icmp eq i32 %12, %1
br i1 %13, label %14, label %4
14: ; preds = %4, %10, %2
%15 = phi i32 [ 0, %2 ], [ %1, %10 ], [ %5, %4 ]
ret i32 %15
}