#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 */
unsigned int strlen(char *);
unsigned strchr(char s[], char f) {
  unsigned i;
  for (i = 0; i < strlen(s); i++) {
    if (s[i] == f)
      return i;
  }
  return -1;
}


x86 assembly (clang, -O0):
<strchr>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %sil,%al
mov    %rdi,-0x10(%rbp)
mov    %al,-0x11(%rbp)
movl   $0x0,-0x18(%rbp)
mov    -0x18(%rbp),%eax
mov    %eax,-0x1c(%rbp)
mov    -0x10(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,%ecx
mov    -0x1c(%rbp),%eax
cmp    %ecx,%eax
jae    117a <strchr+0x6a>
mov    -0x10(%rbp),%rax
mov    -0x18(%rbp),%ecx
movsbl (%rax,%rcx,1),%eax
movsbl -0x11(%rbp),%ecx
cmp    %ecx,%eax
jne    1167 <strchr+0x57>
mov    -0x18(%rbp),%eax
mov    %eax,-0x4(%rbp)
jmp    1181 <strchr+0x71>
jmp    116c <strchr+0x5c>
mov    -0x18(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x18(%rbp)
jmp    1129 <strchr+0x19>
movl   $0xffffffff,-0x4(%rbp)
mov    -0x4(%rbp),%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<strchr>:
push   %rbp
push   %r15
push   %r14
push   %rbx
push   %rax
mov    %esi,%r15d
mov    %rdi,%rbx
call   1030 <strlen@plt>
mov    $0xffffffff,%r14d
test   %eax,%eax
je     114e <strchr+0x3e>
xor    %ebp,%ebp
xchg   %ax,%ax
cmp    %r15b,(%rbx,%rbp,1)
je     114b <strchr+0x3b>
add    $0x1,%rbp
mov    %rbx,%rdi
call   1030 <strlen@plt>
mov    %eax,%eax
cmp    %rax,%rbp
jb     1130 <strchr+0x20>
jmp    114e <strchr+0x3e>
mov    %ebp,%r14d
mov    %r14d,%eax
add    $0x8,%rsp
pop    %rbx
pop    %r14
pop    %r15
pop    %rbp
ret

LLVM IR (-O0):
define i32 @strchr(i8* %0, i8 signext %1) {
%3 = alloca i32
%4 = alloca i8*
%5 = alloca i8
%6 = alloca i32
store i8* %0, i8** %4
store i8 %1, i8* %5
store i32 0, i32* %6
br label %7
7: ; preds = %25, %2
%8 = load i32, i32* %6
%9 = load i8*, i8** %4
%10 = call i32 @strlen(i8* %9)
%11 = icmp ult i32 %8, %10
br i1 %11, label %12, label %28
12: ; preds = %7
%13 = load i8*, i8** %4
%14 = load i32, i32* %6
%15 = zext i32 %14 to i64
%16 = getelementptr inbounds i8, i8* %13, i64 %15
%17 = load i8, i8* %16
%18 = sext i8 %17 to i32
%19 = load i8, i8* %5
%20 = sext i8 %19 to i32
%21 = icmp eq i32 %18, %20
br i1 %21, label %22, label %24
22: ; preds = %12
%23 = load i32, i32* %6
store i32 %23, i32* %3
br label %29
24: ; preds = %12
br label %25
25: ; preds = %24
%26 = load i32, i32* %6
%27 = add i32 %26, 1
store i32 %27, i32* %6
br label %7
28: ; preds = %7
store i32 -1, i32* %3
br label %29
29: ; preds = %28, %22
%30 = load i32, i32* %3
ret i32 %30
}

LLVM IR (-O2):
define i32 @strchr(i8* %0, i8 signext %1) {
%3 = tail call i32 @strlen(i8* %0)
%4 = icmp eq i32 %3, 0
br i1 %4, label %17, label %5
5: ; preds = %2, %10
%6 = phi i64 [ %11, %10 ], [ 0, %2 ]
%7 = getelementptr inbounds i8, i8* %0, i64 %6
%8 = load i8, i8* %7
%9 = icmp eq i8 %8, %1
br i1 %9, label %15, label %10
10: ; preds = %5
%11 = add nuw nsw i64 %6, 1
%12 = tail call i32 @strlen(i8* %0)
%13 = zext i32 %12 to i64
%14 = icmp ult i64 %11, %13
br i1 %14, label %5, label %17
15: ; preds = %5
%16 = trunc i64 %6 to i32
br label %17
17: ; preds = %10, %15, %2
%18 = phi i32 [ -1, %2 ], [ %16, %15 ], [ -1, %10 ]
ret i32 %18
}