#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 */
int strlen(char const *);
char *find_start_of_filename(const char *ch) {
  char *p = (char *)ch + strlen(ch);
  while (p > ch && *p != '\\')
    p--;
  if (*p == '\\')
    p++;
  return p;
}


x86 assembly (clang, -O0):
<find_start_of_filename>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    -0x8(%rbp),%rax
mov    %rax,-0x18(%rbp)
mov    -0x8(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,%ecx
mov    -0x18(%rbp),%rax
movslq %ecx,%rcx
add    %rcx,%rax
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rcx
xor    %eax,%eax
cmp    -0x8(%rbp),%rcx
mov    %al,-0x19(%rbp)
jbe    1160 <find_start_of_filename+0x50>
mov    -0x10(%rbp),%rax
movsbl (%rax),%eax
cmp    $0x5c,%eax
setne  %al
mov    %al,-0x19(%rbp)
mov    -0x19(%rbp),%al
test   $0x1,%al
jne    1170 <find_start_of_filename+0x60>
jmp    1181 <find_start_of_filename+0x71>
mov    -0x10(%rbp),%rax
add    $0xffffffffffffffff,%rax
mov    %rax,-0x10(%rbp)
jmp    113d <find_start_of_filename+0x2d>
mov    -0x10(%rbp),%rax
movsbl (%rax),%eax
cmp    $0x5c,%eax
jne    119d <find_start_of_filename+0x8d>
mov    -0x10(%rbp),%rax
add    $0x1,%rax
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<find_start_of_filename>:
push   %rbx
mov    %rdi,%rbx
call   1030 <strlen@plt>
cltq
lea    (%rbx,%rax,1),%rcx
test   %eax,%eax
jle    113e <find_start_of_filename+0x2e>
cs nopw 0x0(%rax,%rax,1)
nopl   (%rax)
cmpb   $0x5c,(%rcx)
je     113e <find_start_of_filename+0x2e>
add    $0xffffffffffffffff,%rcx
cmp    %rbx,%rcx
ja     1130 <find_start_of_filename+0x20>
xor    %eax,%eax
cmpb   $0x5c,(%rcx)
sete   %al
add    %rcx,%rax
pop    %rbx
ret

LLVM IR (-O0):
define i8* @find_start_of_filename(i8* %0) {
%2 = alloca i8*
%3 = alloca i8*
store i8* %0, i8** %2
%4 = load i8*, i8** %2
%5 = load i8*, i8** %2
%6 = call i32 @strlen(i8* %5)
%7 = sext i32 %6 to i64
%8 = getelementptr inbounds i8, i8* %4, i64 %7
store i8* %8, i8** %3
br label %9
9: ; preds = %20, %1
%10 = load i8*, i8** %3
%11 = load i8*, i8** %2
%12 = icmp ugt i8* %10, %11
br i1 %12, label %13, label %18
13: ; preds = %9
%14 = load i8*, i8** %3
%15 = load i8, i8* %14
%16 = sext i8 %15 to i32
%17 = icmp ne i32 %16, 92
br label %18
18: ; preds = %13, %9
%19 = phi i1 [ false, %9 ], [ %17, %13 ]
br i1 %19, label %20, label %23
20: ; preds = %18
%21 = load i8*, i8** %3
%22 = getelementptr inbounds i8, i8* %21, i32 -1
store i8* %22, i8** %3
br label %9
23: ; preds = %18
%24 = load i8*, i8** %3
%25 = load i8, i8* %24
%26 = sext i8 %25 to i32
%27 = icmp eq i32 %26, 92
br i1 %27, label %28, label %31
28: ; preds = %23
%29 = load i8*, i8** %3
%30 = getelementptr inbounds i8, i8* %29, i32 1
store i8* %30, i8** %3
br label %31
31: ; preds = %28, %23
%32 = load i8*, i8** %3
ret i8* %32
}

LLVM IR (-O2):
define i8* @find_start_of_filename(i8* %0) {
%2 = tail call i32 @strlen(i8* %0)
%3 = sext i32 %2 to i64
%4 = getelementptr inbounds i8, i8* %0, i64 %3
%5 = icmp sgt i32 %2, 0
br i1 %5, label %6, label %13
6: ; preds = %1, %10
%7 = phi i8* [ %11, %10 ], [ %4, %1 ]
%8 = load i8, i8* %7
%9 = icmp eq i8 %8, 92
br i1 %9, label %13, label %10
10: ; preds = %6
%11 = getelementptr inbounds i8, i8* %7, i64 -1
%12 = icmp ugt i8* %11, %0
br i1 %12, label %6, label %13
13: ; preds = %6, %10, %1
%14 = phi i8* [ %4, %1 ], [ %11, %10 ], [ %7, %6 ]
%15 = load i8, i8* %14
%16 = icmp eq i8 %15, 92
%17 = zext i1 %16 to i64
%18 = getelementptr i8, i8* %14, i64 %17
ret i8* %18
}