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Updated: Wednesday, July 27, 2022

FileCheck (1)


FileCheck - Flexible pattern matching file verifier


FileCheck match-filename [--check-prefix=XXX] [--strict-whitespace]


FILECHECK(1)                         LLVM                         FILECHECK(1)

       FileCheck - Flexible pattern matching file verifier

       FileCheck match-filename [--check-prefix=XXX] [--strict-whitespace]

       FileCheck  reads  two files (one from standard input, and one specified
       on the command line) and uses one to verify the other.   This  behavior
       is  particularly  useful  for the testsuite, which wants to verify that
       the output of some tool (e.g. llc) contains  the  expected  information
       (for  example,  a  movsd from esp or whatever is interesting).  This is
       similar to using grep, but it is optimized for matching  multiple  dif-
       ferent inputs in one file in a specific order.

       The  match-filename  file specifies the file that contains the patterns
       to match.  The file to verify is read from standard  input  unless  the
       --input-file option is used.

       Options  are  parsed  from  the environment variable FILECHECK_OPTS and
       from the command line.

       -help  Print a summary of command line options.

       --check-prefix prefix
              FileCheck searches the contents of match-filename  for  patterns
              to   match.   By  default,  these  patterns  are  prefixed  with
              "CHECK:".  If you'd like to use a different prefix (e.g. because
              the  same  input  file  is  checking  multiple different tool or
              options), the --check-prefix  argument  allows  you  to  specify
              (without the trailing ":") one or more prefixes to match. Multi-
              ple prefixes are useful for tests which might change for differ-
              ent run options, but most lines remain the same.

              FileCheck  does  not permit duplicate prefixes, even if one is a
              check prefix and one is a comment prefix (see --comment-prefixes

       --check-prefixes prefix1,prefix2,...
              An  alias  of --check-prefix that allows multiple prefixes to be
              specified as a comma separated list.

       --comment-prefixes prefix1,prefix2,...
              By default, FileCheck ignores any occurrence  in  match-filename
              of any check prefix if it is preceded on the same line by "COM:"
              or "RUN:". See  the  section  The  "COM:"  directive  for  usage

              These   default   comment   prefixes   can   be   overridden  by
              --comment-prefixes if they are not appropriate for your  testing
              environment.  However,  doing  so  is  not recommended in LLVM's
              LIT-based test suites, which should be  easier  to  maintain  if
              they  all  follow a consistent comment style. In that case, con-
              sider  proposing  a  change  to  the  default  comment  prefixes

       --input-file filename
              File to check (defaults to stdin).

              By default, FileCheck allows matches of anywhere on a line. This
              option will require all positive  matches  to  cover  an  entire
              line.   Leading  and  trailing  whitespace  is  ignored,  unless
              --strict-whitespace is also specified. (Note:  negative  matches
              from CHECK-NOT are not affected by this option!)

              Passing  this option is equivalent to inserting {{^ *}} or {{^}}
              before, and {{ *$}} or {{$}} after every positive check pattern.

              By default, FileCheck canonicalizes input horizontal  whitespace
              (spaces and tabs) which causes it to ignore these differences (a
              space will match a tab).  The --strict-whitespace argument  dis-
              ables  this behavior. End-of-line sequences are canonicalized to
              UNIX-style \n in all modes.

              By default, FileCheck uses case-sensitive matching. This  option
              causes FileCheck to use case-insensitive matching.

       --implicit-check-not check-pattern
              Adds implicit negative checks for the specified patterns between
              positive checks. The option allows writing stricter tests  with-
              out stuffing them with CHECK-NOTs.

              For  example, "--implicit-check-not warning:" can be useful when
              testing diagnostic messages from tools that don't have an option
              similar to clang -verify. With this option FileCheck will verify
              that input does not contain warnings not covered by  any  CHECK:

       --dump-input <value>
              Dump  input to stderr, adding annotations representing currently
              enabled diagnostics.  When there  are  multiple  occurrences  of
              this option, the <value> that appears earliest in the list below
              has precedence.  The default is fail.

              o help   - Explain input dump and quit

              o always - Always dump input

              o fail   - Dump input on failure

              o never  - Never dump input

       --dump-input-context <N>
              In the dump requested by --dump-input,  print  <N>  input  lines
              before  and  <N>  input  lines  after  any  lines  specified  by
              --dump-input-filter.  When there  are  multiple  occurrences  of
              this  option,  the  largest  specified  <N> has precedence.  The
              default is 5.

       --dump-input-filter <value>
              In the dump requested by --dump-input, print only input lines of
              kind <value> plus any context specified by --dump-input-context.
              When there are multiple occurrences of this option, the  <value>
              that  appears  earliest  in  the list below has precedence.  The
              default is error  when  --dump-input=fail,  and  it's  all  when

              o all             - All input lines

              o annotation-full - Input lines with annotations

              o annotation       - Input lines with starting points of annota-

              o error           - Input lines with starting  points  of  error

              Enables scope for regex variables.

              Variables with names that start with $ are considered global and
              remain set throughout the file.

              All  other  variables  get  undefined  after  each   encountered

              Sets  a filecheck pattern variable VAR with value VALUE that can
              be used in CHECK: lines.

              Sets a filecheck numeric variable NUMVAR of matching format  FMT
              to  the  result  of  evaluating <NUMERIC EXPRESSION> that can be
              used in CHECK: lines.  See section FileCheck  Numeric  Variables
              and Expressions for details on supported numeric expressions.

              Show the version number of this program.

       -v     Print    good    directive   pattern   matches.    However,   if
              -dump-input=fail or -dump-input=always,  add  those  matches  as
              input annotations instead.

       -vv    Print  information  helpful  in  diagnosing  internal  FileCheck
              issues,  such  as  discarded  overlapping  CHECK-DAG:   matches,
              implicit  EOF  pattern  matches, and CHECK-NOT: patterns that do
              not have matches.  Implies -v.  However, if -dump-input=fail  or
              -dump-input=always,  just  add that information as input annota-
              tions instead.

              Enable overlapping among  matches  in  a  group  of  consecutive
              CHECK-DAG:  directives.   This  option is deprecated and is only
              provided for convenience as old tests are migrated  to  the  new
              non-overlapping CHECK-DAG: implementation.

              Use colors in output (autodetected by default).

       If  FileCheck  verifies that the file matches the expected contents, it
       exits with 0.  Otherwise, if not, or if an error occurs, it  will  exit
       with a non-zero value.

       FileCheck  is  typically used from LLVM regression tests, being invoked
       on the RUN line of the test.  A simple example of using FileCheck  from
       a RUN line looks like this:

          ; RUN: llvm-as < %s | llc -march=x86-64 | FileCheck %s

       This  syntax  says  to  pipe the current file ("%s") into llvm-as, pipe
       that into llc, then pipe the output of llc into FileCheck.  This  means
       that  FileCheck  will  be verifying its standard input (the llc output)
       against the filename argument specified (the original .ll  file  speci-
       fied  by  "%s").   To see how this works, let's look at the rest of the
       .ll file (after the RUN line):

          define void @sub1(i32* %p, i32 %v) {
          ; CHECK: sub1:
          ; CHECK: subl
                  %0 = tail call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %p, i32 %v)
                  ret void

          define void @inc4(i64* %p) {
          ; CHECK: inc4:
          ; CHECK: incq
                  %0 = tail call i64 @llvm.atomic.load.add.i64.p0i64(i64* %p, i64 1)
                  ret void

       Here you can see some "CHECK:" lines specified in  comments.   Now  you
       can  see  how the file is piped into llvm-as, then llc, and the machine
       code output is what we are verifying.   FileCheck  checks  the  machine
       code output to verify that it matches what the "CHECK:" lines specify.

       The syntax of the "CHECK:" lines is very simple: they are fixed strings
       that must occur in order.  FileCheck defaults  to  ignoring  horizontal
       whitespace  differences  (e.g.  a  space is allowed to match a tab) but
       otherwise, the contents of the "CHECK:" line is required to match  some
       thing in the test file exactly.

       One  nice  thing  about  FileCheck (compared to grep) is that it allows
       merging test cases together into logical groups.  For example,  because
       the  test above is checking for the "sub1:" and "inc4:" labels, it will
       not match unless there is a "subl" in  between  those  labels.   If  it
       existed  somewhere  else in the file, that would not count: "grep subl"
       matches if "subl" exists anywhere in the file.

   The FileCheck -check-prefix option
       The FileCheck -check-prefix option allows multiple test  configurations
       to  be driven from one .ll file.  This is useful in many circumstances,
       for example, testing different architectural variants with llc.  Here's
       a simple example:

          ; RUN: llvm-as < %s | llc -mtriple=i686-apple-darwin9 -mattr=sse41 \
          ; RUN:              | FileCheck %s -check-prefix=X32
          ; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin9 -mattr=sse41 \
          ; RUN:              | FileCheck %s -check-prefix=X64

          define <4 x i32> @pinsrd_1(i32 %s, <4 x i32> %tmp) nounwind {
                  %tmp1 = insertelement <4 x i32>; %tmp, i32 %s, i32 1
                  ret <4 x i32> %tmp1
          ; X32: pinsrd_1:
          ; X32:    pinsrd $1, 4(%esp), %xmm0

          ; X64: pinsrd_1:
          ; X64:    pinsrd $1, %edi, %xmm0

       In  this  case,  we're testing that we get the expected code generation
       with both 32-bit and 64-bit code generation.

   The COM: directive
       Sometimes you want to disable a FileCheck directive without removing it
       entirely,  or  you  want  to write comments that mention a directive by
       name. The "COM:" directive makes it easy to do this. For  example,  you
       might have:

          ; X32: pinsrd_1:
          ; X32:    pinsrd $1, 4(%esp), %xmm0

          ; COM: FIXME: X64 isn't working correctly yet for this part of codegen, but
          ; COM: X64 will have something similar to X32:
          ; COM:
          ; COM:   X64: pinsrd_1:
          ; COM:   X64:    pinsrd $1, %edi, %xmm0

       Without "COM:", you would need to use some combination of rewording and
       directive syntax mangling to prevent  FileCheck  from  recognizing  the
       commented  occurrences  of "X32:" and "X64:" above as directives. More-
       over, FileCheck diagnostics have  been  proposed  that  might  complain
       about  the  above occurrences of "X64" that don't have the trailing ":"
       because they look like directive typos. Dodging all these problems  can
       be  tedious  for  a test author, and directive syntax mangling can make
       the purpose of test code unclear.  "COM:" avoids all these problems.

       A few important usage notes:

       o "COM:" within another directive's pattern does not  comment  out  the
         remainder of the pattern. For example:

            ; X32: pinsrd $1, 4(%esp), %xmm0 COM: This is part of the X32 pattern!

         If you need to temporarily comment out part of a directive's pattern,
         move it to another line. The reason is that FileCheck  parses  "COM:"
         in  the  same manner as any other directive: only the first directive
         on the line is recognized as a directive.

       o For the sake of LIT, FileCheck treats "RUN:"  just  like  "COM:".  If
         this    is    not   suitable   for   your   test   environment,   see

       o FileCheck does not recognize "COM", "RUN", or any  user-defined  com-
         ment  prefix  as a comment directive if it's combined with one of the
         usual check directive suffixes, such as  "-NEXT:"  or  "-NOT:",  dis-
         cussed  below.   FileCheck  treats  such  a combination as plain text
         instead. If it needs to act as a  comment  directive  for  your  test
         environment, define it as such with --comment-prefixes.

   The CHECK-NEXT: directive
       Sometimes you want to match lines and would like to verify that matches
       happen on exactly consecutive lines with  no  other  lines  in  between
       them.   In this case, you can use "CHECK:" and "CHECK-NEXT:" directives
       to specify this.  If you specified a  custom  check  prefix,  just  use
       "<PREFIX>-NEXT:".   For  example,  something  like  this works as you'd

          define void @t2(<2 x double>* %r, <2 x double>* %A, double %B) {
               %tmp3 = load <2 x double>* %A, align 16
               %tmp7 = insertelement <2 x double> undef, double %B, i32 0
               %tmp9 = shufflevector <2 x double> %tmp3,
                                      <2 x double> %tmp7,
                                      <2 x i32> < i32 0, i32 2 >
               store <2 x double> %tmp9, <2 x double>* %r, align 16
               ret void

          ; CHECK:          t2:
          ; CHECK:             movl    8(%esp), %eax
          ; CHECK-NEXT:        movapd  (%eax), %xmm0
          ; CHECK-NEXT:        movhpd  12(%esp), %xmm0
          ; CHECK-NEXT:        movl    4(%esp), %eax
          ; CHECK-NEXT:        movapd  %xmm0, (%eax)
          ; CHECK-NEXT:        ret

       "CHECK-NEXT:" directives reject the input unless there is  exactly  one
       newline  between it and the previous directive.  A "CHECK-NEXT:" cannot
       be the first directive in a file.

   The CHECK-SAME: directive
       Sometimes you want to match lines and would like to verify that matches
       happen  on  the same line as the previous match.  In this case, you can
       use "CHECK:" and "CHECK-SAME:" directives  to  specify  this.   If  you
       specified a custom check prefix, just use "<PREFIX>-SAME:".

       "CHECK-SAME:" is particularly powerful in conjunction with "CHECK-NOT:"
       (described below).

       For example, the following works like you'd expect:

          !0 = !DILocation(line: 5, scope: !1, inlinedAt: !2)

          ; CHECK:       !DILocation(line: 5,
          ; CHECK-NOT:               column:
          ; CHECK-SAME:              scope: ![[SCOPE:[0-9]+]]

       "CHECK-SAME:" directives reject the input if  there  are  any  newlines
       between  it  and the previous directive.  A "CHECK-SAME:" cannot be the
       first directive in a file.

   The CHECK-EMPTY: directive
       If you need to check that the next line has nothing  on  it,  not  even
       whitespace, you can use the "CHECK-EMPTY:" directive.

          declare void @foo()

          declare void @bar()
          ; CHECK: foo
          ; CHECK-EMPTY:
          ; CHECK-NEXT: bar

       Just  like  "CHECK-NEXT:" the directive will fail if there is more than
       one newline before it finds the next blank line, and it cannot  be  the
       first directive in a file.

   The CHECK-NOT: directive
       The  "CHECK-NOT:"  directive  is  used  to verify that a string doesn't
       occur between two matches (or before the first match, or after the last
       match).  For example, to verify that a load is removed by a transforma-
       tion, a test like this can be used:

          define i8 @coerce_offset0(i32 %V, i32* %P) {
            store i32 %V, i32* %P

            %P2 = bitcast i32* %P to i8*
            %P3 = getelementptr i8* %P2, i32 2

            %A = load i8* %P3
            ret i8 %A
          ; CHECK: @coerce_offset0
          ; CHECK-NOT: load
          ; CHECK: ret i8

   The CHECK-COUNT: directive
       If you need to match multiple lines with the same pattern over and over
       again  you  can  repeat a plain CHECK: as many times as needed. If that
       looks   too   boring   you   can   instead   use   a   counted    check
       "CHECK-COUNT-<num>:", where <num> is a positive decimal number. It will
       match the pattern exactly <num> times, no more  and  no  less.  If  you
       specified  a  custom check prefix, just use "<PREFIX>-COUNT-<num>:" for
       the same effect.  Here is a simple example:

          Loop at depth 1
          Loop at depth 1
          Loop at depth 1
          Loop at depth 1
            Loop at depth 2
              Loop at depth 3

          ; CHECK-COUNT-6: Loop at depth {{[0-9]+}}
          ; CHECK-NOT:     Loop at depth {{[0-9]+}}

   The CHECK-DAG: directive
       If it's necessary to match strings  that  don't  occur  in  a  strictly
       sequential order, "CHECK-DAG:" could be used to verify them between two
       matches (or before the first match, or after the last match). For exam-
       ple,  clang emits vtable globals in reverse order. Using CHECK-DAG:, we
       can keep the checks in the natural order:

          // RUN: %clang_cc1 %s -emit-llvm -o - | FileCheck %s

          struct Foo { virtual void method(); };
          Foo f;  // emit vtable
          // CHECK-DAG: @_ZTV3Foo =

          struct Bar { virtual void method(); };
          Bar b;
          // CHECK-DAG: @_ZTV3Bar =

       CHECK-NOT: directives could be  mixed  with  CHECK-DAG:  directives  to
       exclude  strings  between  the  surrounding CHECK-DAG: directives. As a
       result, the surrounding CHECK-DAG: directives cannot be reordered, i.e.
       all  occurrences  matching  CHECK-DAG:  before CHECK-NOT: must not fall
       behind occurrences matching CHECK-DAG: after CHECK-NOT:. For example,

          ; CHECK-DAG: BEFORE
          ; CHECK-NOT: NOT
          ; CHECK-DAG: AFTER

       This case will reject input strings where BEFORE occurs after AFTER.

       With captured variables, CHECK-DAG: is able to match valid  topological
       orderings  of a DAG with edges from the definition of a variable to its
       use.  It's useful, e.g., when your test cases need to  match  different
       output sequences from the instruction scheduler. For example,

          ; CHECK-DAG: add [[REG1:r[0-9]+]], r1, r2
          ; CHECK-DAG: add [[REG2:r[0-9]+]], r3, r4
          ; CHECK:     mul r5, [[REG1]], [[REG2]]

       In this case, any order of that two add instructions will be allowed.

       If  you  are defining and using variables in the same CHECK-DAG: block,
       be aware that the definition rule can match after its use.

       So, for instance, the code below will pass:

          ; CHECK-DAG: vmov.32 [[REG2:d[0-9]+]][0]
          ; CHECK-DAG: vmov.32 [[REG2]][1]
          vmov.32 d0[1]
          vmov.32 d0[0]

       While this other code, will not:

          ; CHECK-DAG: vmov.32 [[REG2:d[0-9]+]][0]
          ; CHECK-DAG: vmov.32 [[REG2]][1]
          vmov.32 d1[1]
          vmov.32 d0[0]

       While this can be very useful, it's also dangerous, because in the case
       of  register sequence, you must have a strong order (read before write,
       copy before use, etc). If the  definition  your  test  is  looking  for
       doesn't  match (because of a bug in the compiler), it may match further
       away from the use, and mask real bugs away.

       In those cases, to enforce the order, use a non-DAG  directive  between

       A  CHECK-DAG:  directive  skips matches that overlap the matches of any
       preceding CHECK-DAG: directives in the same CHECK-DAG: block.  Not only
       is  this non-overlapping behavior consistent with other directives, but
       it's also necessary to handle sets of non-unique strings  or  patterns.
       For  example,  the  following directives look for unordered log entries
       for two tasks in a parallel program, such as the OpenMP runtime:

          // CHECK-DAG: [[THREAD_ID:[0-9]+]]: task_begin
          // CHECK-DAG: [[THREAD_ID]]: task_end
          // CHECK-DAG: [[THREAD_ID:[0-9]+]]: task_begin
          // CHECK-DAG: [[THREAD_ID]]: task_end

       The second pair of directives is guaranteed not to match the  same  log
       entries  as  the  first pair even though the patterns are identical and
       even if the text of the log entries is identical because the thread  ID
       manages to be reused.

   The CHECK-LABEL: directive
       Sometimes  in  a  file  containing  multiple tests divided into logical
       blocks, one or more CHECK:  directives  may  inadvertently  succeed  by
       matching lines in a later block. While an error will usually eventually
       be generated, the check flagged as causing the error may  not  actually
       bear any relationship to the actual source of the problem.

       In  order  to  produce  better  error  messages  in  these  cases,  the
       "CHECK-LABEL:" directive can be used. It is treated  identically  to  a
       normal  CHECK  directive  except  that  FileCheck  makes  an additional
       assumption that a line matched by the directive cannot also be  matched
       by  any  other  check present in match-filename; this is intended to be
       used for lines containing labels or other unique identifiers. Conceptu-
       ally,  the  presence of CHECK-LABEL divides the input stream into sepa-
       rate blocks, each of which is  processed  independently,  preventing  a
       CHECK:  directive  in  one  block matching a line in another block.  If
       --enable-var-scope is in effect, all local variables are cleared at the
       beginning of the block.

       For example,

          define %struct.C* @C_ctor_base(%struct.C* %this, i32 %x) {
          ; CHECK-LABEL: C_ctor_base:
          ; CHECK: mov [[SAVETHIS:r[0-9]+]], r0
          ; CHECK: bl A_ctor_base
          ; CHECK: mov r0, [[SAVETHIS]]
            %0 = bitcast %struct.C* %this to %struct.A*
            %call = tail call %struct.A* @A_ctor_base(%struct.A* %0)
            %1 = bitcast %struct.C* %this to %struct.B*
            %call2 = tail call %struct.B* @B_ctor_base(%struct.B* %1, i32 %x)
            ret %struct.C* %this

          define %struct.D* @D_ctor_base(%struct.D* %this, i32 %x) {
          ; CHECK-LABEL: D_ctor_base:

       The  use of CHECK-LABEL: directives in this case ensures that the three
       CHECK: directives only accept lines corresponding to the  body  of  the
       @C_ctor_base  function, even if the patterns match lines found later in
       the file. Furthermore, if one of these three  CHECK:  directives  fail,
       FileCheck will recover by continuing to the next block, allowing multi-
       ple test failures to be detected in a single invocation.

       There is no requirement that CHECK-LABEL:  directives  contain  strings
       that  correspond  to actual syntactic labels in a source or output lan-
       guage: they must simply uniquely match a single line in the file  being

       CHECK-LABEL: directives cannot contain variable definitions or uses.

   FileCheck Regex Matching Syntax
       All  FileCheck  directives  take  a pattern to match.  For most uses of
       FileCheck, fixed string matching is  perfectly  sufficient.   For  some
       things,  a more flexible form of matching is desired.  To support this,
       FileCheck  allows  you  to  specify  regular  expressions  in  matching
       strings,  surrounded  by double braces: {{yourregex}}. FileCheck imple-
       ments a POSIX regular expression matcher; it  supports  Extended  POSIX
       regular expressions (ERE). Because we want to use fixed string matching
       for a majority of what we do, FileCheck has been  designed  to  support
       mixing  and  matching  fixed  string matching with regular expressions.
       This allows you to write things like this:

          ; CHECK: movhpd      {{[0-9]+}}(%esp), {{%xmm[0-7]}}

       In this case, any offset from the ESP register will be allowed, and any
       xmm register will be allowed.

       Because  regular  expressions are enclosed with double braces, they are
       visually distinct, and you don't need to use escape  characters  within
       the  double braces like you would in C.  In the rare case that you want
       to match double braces explicitly from the input, you can use something
       ugly  like {{[}][}]}} as your pattern.  Or if you are using the repeti-
       tion count syntax, for example [[:xdigit:]]{8} to match exactly  8  hex
       digits,    you    would    need    to   add   parentheses   like   this
       {{([[:xdigit:]]{8})}} to avoid confusion with FileCheck's closing  dou-

   FileCheck String Substitution Blocks
       It  is  often  useful to match a pattern and then verify that it occurs
       again later in the file.  For codegen tests,  this  can  be  useful  to
       allow  any register, but verify that that register is used consistently
       later.  To do this, FileCheck supports string substitution blocks  that
       allow  string  variables  to  be defined and substituted into patterns.
       Here is a simple example:

          ; CHECK: test5:
          ; CHECK:    notw     [[REGISTER:%[a-z]+]]
          ; CHECK:    andw     {{.*}}[[REGISTER]]

       The first check line matches a regex %[a-z]+ and captures it  into  the
       string variable REGISTER.  The second line verifies that whatever is in
       REGISTER occurs later in the file after  an  "andw".  FileCheck  string
       substitution  blocks  are  always  contained in [[ ]] pairs, and string
       variable names can be formed with the regex [a-zA-Z_][a-zA-Z0-9_]*.  If
       a colon follows the name, then it is a definition of the variable; oth-
       erwise, it is a substitution.

       FileCheck variables can be defined multiple  times,  and  substitutions
       always  get  the latest value.  Variables can also be substituted later
       on the same line they were defined on. For example:

          ; CHECK: op [[REG:r[0-9]+]], [[REG]]

       Can be useful if you want the operands of op to be the  same  register,
       and don't care exactly which register it is.

       If  --enable-var-scope  is  in  effect, variables with names that start
       with $ are considered to be global. All  others  variables  are  local.
       All  local variables get undefined at the beginning of each CHECK-LABEL
       block. Global variables are not affected by CHECK-LABEL.  This makes it
       easier  to  ensure  that individual tests are not affected by variables
       set in preceding tests.

   FileCheck Numeric Substitution Blocks
       FileCheck also supports numeric substitution blocks that allow defining
       numeric  variables  and  checking  for  numeric  values  that satisfy a
       numeric expression constraint based on those variables  via  a  numeric
       substitution.  This  allows CHECK: directives to verify a numeric rela-
       tion between two numbers, such as the need for consecutive registers to
       be used.

       The  syntax  to  define a numeric variable is [[#%<fmtspec>,<NUMVAR>:]]

       o %<fmtspec> is an optional scanf-style matching  format  specifier  to
         indicate  what  number  format to match (e.g. hex number).  Currently
         accepted format specifiers are %u, %d, %x and  %X.   If  absent,  the
         format specifier defaults to %u.

       o <NUMVAR>  is the name of the numeric variable to define to the match-
         ing value.

       For example:

          ; CHECK: mov r[[#REG:]], 0x[[#%X,IMM:]]

       would match mov r5, 0xF0F0 and set REG to the value 5 and  IMM  to  the
       value 0xF0F0.

       The  syntax  of  a  numeric substitution is [[#%<fmtspec>: <constraint>
       <expr>]] where:

       o %<fmtspec> is the same matching  format  specifier  as  for  defining
         numeric variables but acting as a printf-style format to indicate how
         a numeric expression value should be matched against.  If absent, the
         format  specifier is inferred from the matching format of the numeric
         variable(s) used by the expression constraint if any, and defaults to
         %u  if  no  numeric  variable  is  used.  In case of conflict between
         matching formats of several numeric variables the format specifier is

       o <constraint> is the constraint describing how the value to match must
         relate to the value of the numeric  expression.  The  only  currently
         accepted  constraint  is  == for an exact match and is the default if
         <constraint> is not provided. No matching constraint must  be  speci-
         fied when the <expr> is empty.

       o <expr> is an expression. An expression is in turn recursively defined

         o a numeric operand, or

         o an expression followed by an operator and a numeric operand.

         A numeric operand is a previously defined numeric variable, an  inte-
         ger  literal,  or  a  function. Spaces are accepted before, after and
         between any of these elements. Numeric operands  have  64-bit  preci-
         sion.  Overflow  and  underflow are rejected. There is no support for
         operator precedence, but parentheses can be used to change the evalu-
         ation order.

       The supported operators are:

          o + - Returns the sum of its two operands.

          o - - Returns the difference of its two operands.

       The syntax of a function call is <name>(<arguments>) where:

       o name is a predefined string literal. Accepted values are:

         o add - Returns the sum of its two operands.

         o div - Returns the quotient of its two operands.

         o max - Returns the largest of its two operands.

         o min - Returns the smallest of its two operands.

         o mul - Returns the product of its two operands.

         o sub - Returns the difference of its two operands.

       o <arguments> is a comma separated list of expressions.

       For example:

          ; CHECK: load r[[#REG:]], [r0]
          ; CHECK: load r[[#REG+1]], [r1]
          ; CHECK: Loading from 0x[[#%x,ADDR:]]
          ; CHECK-SAME: to 0x[[#ADDR + 7]]

       The above example would match the text:

          load r5, [r0]
          load r6, [r1]
          Loading from 0xa0463440 to 0xa0463447

       but would not match the text:

          load r5, [r0]
          load r7, [r1]
          Loading from 0xa0463440 to 0xa0463443

       Due  to 7 being unequal to 5 + 1 and a0463443 being unequal to a0463440
       + 7.

       The syntax also supports an empty  expression,  equivalent  to  writing
       {{[0-9]+}},  for cases where the input must contain a numeric value but
       the value itself does not matter:

          ; CHECK-NOT: mov r0, r[[#]]

       to check that a value is synthesized rather than moved around.

       A numeric variable can also be defined  to  the  result  of  a  numeric
       expression,  in which case the numeric expression constraint is checked
       and if verified the variable is assigned to the value. The unified syn-
       tax  for both defining numeric variables and checking a numeric expres-
       sion is thus [[#%<fmtspec>,<NUMVAR>: <constraint>  <expr>]]  with  each
       element  as  described  previously.  One  can use this syntax to make a
       testcase more self-describing by using variables instead of values:

          ; CHECK: mov r[[#REG_OFFSET:]], 0x[[#%X,FIELD_OFFSET:12]]
          ; CHECK-NEXT: load r[[#]], [r[[#REG_BASE:]], r[[#REG_OFFSET]]]

       which would match:

          mov r4, 0xC
          load r6, [r5, r4]

       The --enable-var-scope option has the same effect on numeric  variables
       as on string variables.

       Important note: In its current implementation, an expression cannot use
       a numeric variable defined earlier in the same CHECK directive.

   FileCheck Pseudo Numeric Variables
       Sometimes there's a need to verify output that contains line numbers of
       the  match  file,  e.g. when testing compiler diagnostics.  This intro-
       duces a certain fragility of the  match  file  structure,  as  "CHECK:"
       lines  contain absolute line numbers in the same file, which have to be
       updated whenever line numbers change due to text addition or deletion.

       To support this case, FileCheck expressions understand the @LINE pseudo
       numeric  variable  which evaluates to the line number of the CHECK pat-
       tern where it is found.

       This way match patterns can be put near the  relevant  test  lines  and
       include relative line number references, for example:

          // CHECK: test.cpp:[[# @LINE + 4]]:6: error: expected ';' after top level declarator
          // CHECK-NEXT: {{^int a}}
          // CHECK-NEXT: {{^     \^}}
          // CHECK-NEXT: {{^     ;}}
          int a

       To support legacy uses of @LINE as a special string variable, FileCheck
       also accepts the following uses of @LINE with string substitution block
       syntax:  [[@LINE]],  [[@LINE+<offset>]]  and [[@LINE-<offset>]] without
       any spaces inside the brackets and where offset is an integer.

   Matching Newline Characters
       To match newline characters in regular expressions the character  class
       [[:space:]] can be used. For example, the following pattern:

          // CHECK: DW_AT_location [DW_FORM_sec_offset] ([[DLOC:0x[0-9a-f]+]]){{[[:space:]].*}}"intd"

       matches output of the form (from llvm-dwarfdump):

          DW_AT_location [DW_FORM_sec_offset]   (0x00000233)
          DW_AT_name [DW_FORM_strp]  ( .debug_str[0x000000c9] = "intd")

       letting  us  set  the  FileCheck  variable  DLOC  to  the desired value
       0x00000233, extracted from the line immediately preceding "intd".

       Maintained by the LLVM Team (https://llvm.org/).

       2003-2022, LLVM Project

       See attributes(7) for descriptions of the following attributes:

       |Availability   | developer/llvm/llvm |
       |Stability      | Uncommitted         |

       Source code for open source software components in Oracle  Solaris  can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-

       This    software    was    built    from    source     available     at
       https://github.com/oracle/solaris-userland.    The  original  community
       source    was    downloaded     from      https://github.com/llvm/llvm-

       Further information about this software can be found on the open source
       community website at https://llvm.org/.

11                                2022-06-28                      FILECHECK(1)