|  | RUN: printf "%%s\n" "\"" | FileCheck %s --check-prefix=CHECK1 | 
|  | RUN: printf "%%s\n" '"' | FileCheck %s --check-prefix=CHECK1 | 
|  | RUN: printf "%%s\n" 'a[b\c' | FileCheck %s --check-prefix=CHECK2 | 
|  | RUN: printf "%%s\n" "a[b\\c" | FileCheck %s --check-prefix=CHECK2 | 
|  | RUN: printf "%%s\n" 'a\b\\c\\\\d' | FileCheck %s --check-prefix=CHECK3 | 
|  | RUN: printf "%%s\n" "a\\b\\\\c\\\\\\\\d" | FileCheck %s --check-prefix=CHECK3 | 
|  | CHECK1: {{^"$}} | 
|  | CHECK2: {{^a\[b\\c$}} | 
|  | CHECK3: {{^a\\b\\\\c\\\\\\\\d$}} | 
|  |  | 
|  | On Windows, with MSYS based tools, the following commands fail though: | 
|  | RUNX: printf "%%s\n" 'a[b\c\\d' | FileCheck %s --check-prefix=CHECK4 | 
|  | RUNX: printf "%%s\n" "a[b\\c\\\\d" | FileCheck %s --check-prefix=CHECK4 | 
|  | CHECK4: {{^a\[b\\c\\\\d$}} |