#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__ strchr(char const *, char const);
size_t strspn(const char *s, const char *accept) {
  size_t count = 0;
  for (; *s; s++) {
    if (strchr(accept, *s))
      count++;
    else
      break;
  }
  return count;
}


x86 assembly (clang, -O0):
<strspn>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
movq   $0x0,-0x18(%rbp)
mov    -0x8(%rbp),%rax
cmpb   $0x0,(%rax)
je     117b <strspn+0x6b>
mov    -0x10(%rbp),%rdi
mov    -0x8(%rbp),%rax
movsbl (%rax),%esi
call   1030 <strchr@plt>
cmp    $0x0,%rax
je     1160 <strspn+0x50>
mov    -0x18(%rbp),%rax
add    $0x1,%rax
mov    %rax,-0x18(%rbp)
jmp    1165 <strspn+0x55>
jmp    117b <strspn+0x6b>
jmp    116a <strspn+0x5a>
mov    -0x8(%rbp),%rax
add    $0x1,%rax
mov    %rax,-0x8(%rbp)
jmp    1128 <strspn+0x18>
mov    -0x18(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<strspn>:
push   %r15
push   %r14
push   %rbx
mov    (%rdi),%al
test   %al,%al
je     1150 <strspn+0x40>
mov    %rsi,%r14
mov    %rdi,%r15
xor    %ebx,%ebx
cs nopw 0x0(%rax,%rax,1)
nopl   (%rax)
movsbl %al,%esi
mov    %r14,%rdi
call   1030 <strchr@plt>
test   %rax,%rax
je     1152 <strspn+0x42>
movzbl 0x1(%r15,%rbx,1),%eax
add    $0x1,%rbx
test   %al,%al
jne    1130 <strspn+0x20>
jmp    1152 <strspn+0x42>
xor    %ebx,%ebx
mov    %rbx,%rax
pop    %rbx
pop    %r14
pop    %r15
ret

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

LLVM IR (-O2):
define i64 @strspn(i8* nocapture %0, i8* %1) {
%3 = load i8, i8* %0
%4 = icmp eq i8 %3, 0
br i1 %4, label %16, label %5
5: ; preds = %2, %11
%6 = phi i8 [ %14, %11 ], [ %3, %2 ]
%7 = phi i64 [ %12, %11 ], [ 0, %2 ]
%8 = phi i8* [ %13, %11 ], [ %0, %2 ]
%9 = tail call i64 @strchr(i8* %1, i8 signext %6)
%10 = icmp eq i64 %9, 0
br i1 %10, label %16, label %11
11: ; preds = %5
%12 = add i64 %7, 1
%13 = getelementptr inbounds i8, i8* %8, i64 1
%14 = load i8, i8* %13
%15 = icmp eq i8 %14, 0
br i1 %15, label %16, label %5
16: ; preds = %11, %5, %2
%17 = phi i64 [ 0, %2 ], [ %7, %5 ], [ %12, %11 ]
ret i64 %17
}