diff --git a/llvm/docs/CommandGuide/FileCheck.rst b/llvm/docs/CommandGuide/FileCheck.rst
--- a/llvm/docs/CommandGuide/FileCheck.rst
+++ b/llvm/docs/CommandGuide/FileCheck.rst
@@ -105,6 +105,11 @@
   Sets a filecheck pattern variable ``VAR`` with value ``VALUE`` that can be
   used in ``CHECK:`` lines.
 
+.. option:: -D#<NUMVAR>=<VALUE>
+
+  Sets a filecheck numeric variable ``VAR`` to ``<VALUE>`` that can be used
+  in ``CHECK:`` lines.
+
 .. option:: -version
 
  Show the version number of this program.
@@ -560,8 +565,52 @@
 This makes it easier to ensure that individual tests are not affected
 by variables set in preceding tests.
 
-FileCheck Numeric Expressions
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+FileCheck Numeric Variables and Expressions
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+:program:`FileCheck` also allows to check for numeric values satisfying a
+numeric expression constraint based on numeric variables. This allows to
+capture numeric relations between two numbers in a text to check, such as the
+the need for consecutive registers to be used.
+
+The syntax to check a numeric expression constraint is
+``[[#<NUMVAR><op><offset>]]`` where:
+
+*``<NUMVAR>`` is the name of a numeric variable defined on the command line.
+
+*``<op>`` is an optional numeric operation to perform on the value of
+``<NUMVAR>``. Currently supported numeric operations are ``+`` and ``-``.
+
+*``<offset>`` is the immediate value that constitutes the second operand of
+the numeric operation <op>. It must be present if ``<op>`` is present,
+absent otherwise.
+
+For example:
+
+.. code-block:: llvm
+
+    ; CHECK: add r[[#REG]], r[[#REG]], r[[#REG+1]]
+
+The above example would match the lines:
+
+.. code-block:: llvm
+
+    add r5, r5, r6
+
+but would not match the lines:
+
+.. code-block:: llvm
+
+    add r5, r5, r7
+
+due to ``7`` being unequal to ``5 + 1``.
+
+In the same way as for pattern variables, ``--enable-var-scope`` only consider
+global numeric variables that start with ``$`` and undefined local variables at
+the beginning of each CHECK-LABEL block.
+
+FileCheck Pseudo Numeric Variables
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Sometimes there's a need to verify output which contains line numbers of the
 match file, e.g. when testing compiler diagnostics.  This introduces a certain
@@ -569,11 +618,9 @@
 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 allows using ``[[#@LINE]]``,
-``[[#@LINE+<offset>]]``, ``[[#@LINE-<offset>]]`` numeric expressions in
-patterns, with arbitrary number of space between each elements of the
-expression. These expressions expand to a number of the line where a pattern
-is located (with an optional integer offset).
+To support this case, FileCheck understands the ``@LINE`` pseudo numeric
+variable which evaluate to the line number of the CHECK pattern where it is
+found.
 
 This way match patterns can be put near the relevant test lines and include
 relative line number references, for example:
diff --git a/llvm/include/llvm/Support/FileCheck.h b/llvm/include/llvm/Support/FileCheck.h
--- a/llvm/include/llvm/Support/FileCheck.h
+++ b/llvm/include/llvm/Support/FileCheck.h
@@ -40,20 +40,86 @@
 // Numeric expression handling code.
 //===----------------------------------------------------------------------===//
 
+class FileCheckASTBinop;
+
 /// Class representing a numeric expression.
 class FileCheckNumExpr {
 private:
-  /// Value of the numeric expression..
+  /// Pointer to AST of the numeric expression.
+  std::unique_ptr<FileCheckASTBinop> AST;
+
+public:
+  /// Generic constructor for a numeric expression whose equality constraint is
+  /// represented by \p AST.
+  FileCheckNumExpr(FileCheckASTBinop *AST) : AST(std::move(AST)) {}
+
+  /// Return pointer to AST of the numeric expression. Pointer is guaranteed to
+  /// be valid as long as this object is.
+  FileCheckASTBinop *getAST() const { return AST.get(); }
+};
+
+/// Class representing a numeric variable with a given value in the AST of a
+/// numeric expression.
+class FileCheckNumVar {
+private:
+  /// Name of the numeric variable.
+  StringRef Name;
+
+  /// Whether variable is defined and thus Value is set.
+  bool Defined;
+
+  /// Value of numeric variable if defined.
   uint64_t Value;
 
 public:
-  /// Constructor for a numeric expression with a known value at parse time,
-  /// e.g. the implicit numeric expression defining the @LINE numeric pseudo
-  /// variable.
-  explicit FileCheckNumExpr(uint64_t Value) : Value(Value) {}
+  /// Constructor for numeric variable \p Name with a known \p Value at parse
+  /// time (e.g. the @LINE numeric variable).
+  explicit FileCheckNumVar(StringRef Name, uint64_t Value)
+      : Name(Name), Defined(true), Value(Value) {}
+
+  /// Return name of that numeric variable.
+  StringRef getName() const { return Name; }
+
+  /// Return value of this numeric variable.
+  llvm::Optional<uint64_t> getValue() const;
+
+  /// Set value of this numeric variable if not defined. Return whether
+  /// the variable was already defined.
+  bool setValue(uint64_t Value);
 
-  /// Return the value being matched against.
-  uint64_t getValue() const { return Value; }
+  /// Clear value of this numeric variable. Return whether the variable was
+  /// already undefined.
+  bool clearValue();
+};
+
+/// Type of functions evaluating a given binary operation.
+using binop_eval_t = uint64_t (*)(uint64_t, uint64_t);
+
+/// Class representing a single binary operation in the AST of a numeric
+/// expression.
+class FileCheckASTBinop {
+private:
+  /// Left operand.
+  FileCheckNumVar *Opl;
+
+  /// Right operand.
+  uint64_t Opr;
+
+  /// Pointer to function that can evaluate this binary operation.
+  binop_eval_t EvalBinop;
+
+public:
+  FileCheckASTBinop(binop_eval_t EvalBinop, FileCheckNumVar *OperandLeft,
+                    uint64_t OperandRight)
+      : Opl(OperandLeft), Opr(OperandRight), EvalBinop(EvalBinop) {}
+
+  /// Evaluate the value of the binary operation represented by this AST. Uses
+  /// EvalBinop to perform the binary operation.
+  llvm::Optional<uint64_t> eval() const;
+
+  /// Return the name of the undefined variable used in this substitution if
+  /// any or an empty string otherwise.
+  StringRef getUndefVarName() const;
 };
 
 class FileCheckPatternContext;
@@ -174,19 +240,34 @@
   /// back-references are used for uses after any the other definition.
   StringMap<StringRef> GlobalVariableTable;
 
+  /// Map of all pattern variables defined so far. Used at parse time to detect
+  /// a name conflict between a numeric variable and a pattern variable when
+  /// the former is defined on a later line than the latter.
+  StringMap<bool> DefinedVariableTable;
+
+  /// When matching a given pattern, this holds the pointers to the classes
+  /// representing the AST of all numeric variables defined in previous
+  /// patterns along with their values. In a pattern, only the last definition
+  /// for a given variable is recorded in this table.
+  StringMap<FileCheckNumVar *> GlobalNumericVariableTable;
+
   /// Vector holding pointers to all numeric expressions parsed. Used to
   /// automatically free the numeric expressions once they are guaranteed to no
   /// longer be used.
   std::vector<std::unique_ptr<FileCheckNumExpr>> NumExprs;
 
+  /// Vector holding pointers to all numeric variables parsed. Used to
+  /// automatically free them once they are guaranteed to no longer be used.
+  std::vector<std::unique_ptr<FileCheckNumVar>> NumVars;
+
 public:
   /// Return the value of pattern variable \p VarName or None if no such
   /// variable has been defined.
   llvm::Optional<StringRef> getPatternVarValue(StringRef VarName);
 
-  /// Define pattern variables from definitions given on the command  line
-  /// passed as a vector of VAR=VAL strings in \p CmdlineDefines. Report any
-  /// error to \p SM and return whether an error occured.
+  /// Define pattern and numeric variables from definitions given on the
+  /// command line passed as a vector of VAR=VAL strings in \p CmdlineDefines.
+  /// Report any error to \p SM and return whether an error occured.
   bool defineCmdlineVariables(std::vector<std::string> &CmdlineDefines,
                               SourceMgr &SM);
 
@@ -197,7 +278,11 @@
 private:
   /// Register a numeric expression for destruction when the context is
   /// destroyed.
-  template <class... Types> FileCheckNumExpr *registerNumExpr(Types... Args);
+  FileCheckNumExpr *registerNumExpr(FileCheckASTBinop *AST);
+
+  /// Make a new numeric variable and register it for destruction when the
+  /// context is destroyed.
+  FileCheckNumVar *makeNumVar(StringRef Name, uint64_t Value);
 };
 
 class FileCheckPattern {
@@ -213,12 +298,12 @@
 
   /// Entries in this vector represent uses of a pattern variable or a numeric
   /// expression in the pattern that need to be substituted in the regexp
-  /// pattern at match time, e.g. "foo[[bar]]baz[[#@LINE+1]]". In this case,
-  /// the RegExStr will contain "foobaz" and we'll get two entries in this
-  /// vector that tells us to insert the value of pattern variable "bar" at
-  /// offset 3 and the value of numeric expression "@LINE+1" at offset 6. Uses
-  /// are represented by a FileCheckPatternSubst class to abstract whether it
-  /// is a pattern variable or a numeric expression.
+  /// pattern at match time, e.g. "foo[[bar]]baz[[#N+1]]". In this case, the
+  /// RegExStr will contain "foobaz" and we'll get two entries in this vector
+  /// that tells us to insert the value of pattern variable "bar" at offset 3
+  /// and the value of numeric expression "N+1" at offset 6. Uses are
+  /// represented by a FileCheckPatternSubst class to abstract whether it is a
+  /// pattern variable or a numeric expression.
   std::vector<FileCheckPatternSubst> Substs;
 
   /// Maps names of pattern variables defined in a pattern to the parenthesized
@@ -232,8 +317,12 @@
   /// iterating over values.
   std::map<StringRef, unsigned> VariableDefs;
 
-  /// Pointer to the class instance shared by all patterns holding a table with
-  /// the values of live variables at the start of any given CHECK line.
+  /// Pointer to a class instance holding the global state shared by all
+  /// patterns:
+  /// - tables with the values of live pattern and numeric variables at
+  ///   the start of any given CHECK line;
+  /// - table holding whether a pattern variable has been defined at any given
+  ///   point during the parsing phase.
   FileCheckPatternContext *Context;
 
   Check::FileCheckType CheckTy;
@@ -260,11 +349,13 @@
   /// variable and \p TrailIdx to the position of the last character that is
   /// part of the variable name. Otherwise, only return true.
   static bool parseVariable(StringRef Str, bool &IsPseudo, unsigned &TrailIdx);
-  /// Parse a numeric expression involving pseudo variable \p Name with the
-  /// string corresponding to the operation being performed in \p Trailer.
-  /// Return the class representing the numeric expression or nullptr if
-  /// parsing fails in which case errors are reported on \p SM.
-  FileCheckNumExpr *parseNumericExpression(StringRef Name, StringRef Trailer,
+  /// Parse a numeric expression involving (pseudo if \p IsPseudo is true)
+  /// variable \p Name with the string corresponding to the operation being
+  /// performed in \p Trailer. Return the class representing the numeric
+  /// expression or nullptr if parsing fails in which case errors are reported
+  /// on \p SM.
+  FileCheckNumExpr *parseNumericExpression(StringRef Name, bool IsPseudo,
+                                           StringRef Trailer,
                                            const SourceMgr &SM) const;
   bool ParsePattern(StringRef PatternStr, StringRef Prefix, SourceMgr &SM,
                     unsigned LineNumber, const FileCheckRequest &Req);
diff --git a/llvm/lib/Support/FileCheck.cpp b/llvm/lib/Support/FileCheck.cpp
--- a/llvm/lib/Support/FileCheck.cpp
+++ b/llvm/lib/Support/FileCheck.cpp
@@ -24,9 +24,47 @@
 
 using namespace llvm;
 
+llvm::Optional<uint64_t> FileCheckNumVar::getValue() const {
+  if (!Defined)
+    return llvm::None;
+  return Value;
+}
+
+bool FileCheckNumVar::setValue(uint64_t Value) {
+  if (Defined)
+    return true;
+  this->Value = Value;
+  this->Defined = true;
+  return false;
+}
+
+bool FileCheckNumVar::clearValue() {
+  if (!Defined)
+    return true;
+  Defined = false;
+  return false;
+}
+
+llvm::Optional<uint64_t> FileCheckASTBinop::eval() const {
+  llvm::Optional<uint64_t> Opl = this->Opl->getValue();
+  // Variable has been undefined.
+  if (!Opl)
+    return llvm::None;
+  return EvalBinop(*Opl, Opr);
+}
+
+StringRef FileCheckASTBinop::getUndefVarName() const {
+  if (!Opl->getValue())
+    return Opl->getName();
+  return StringRef();
+}
+
 llvm::Optional<std::string> FileCheckPatternSubst::getSubstitute() const {
   if (IsNumExpr) {
-    return utostr(NumExpr->getValue());
+    llvm::Optional<uint64_t> EvaluatedValue = NumExpr->getAST()->eval();
+    if (!EvaluatedValue)
+      return llvm::None;
+    return utostr(*EvaluatedValue);
   } else {
     // Look up the value and escape it so that we can put it into the
     // regex.
@@ -38,15 +76,16 @@
 }
 
 StringRef FileCheckPatternSubst::getUndefVarName() const {
-  // Parsing guarantees only @LINE is ever referenced and it is not undefined
-  // by ClearLocalVars.
   if (IsNumExpr)
-    return StringRef();
-
-  if (!Context->getPatternVarValue(SubstStr))
-    return SubstStr;
+    // Although use of undefined numeric variable is tested at parse time,
+    // numeric variable can get undefined later by ClearLocalVariables.
+    return NumExpr->getAST()->getUndefVarName();
+  else {
+    if (!Context->getPatternVarValue(SubstStr))
+      return SubstStr;
 
-  return StringRef();
+    return StringRef();
+  }
 }
 
 bool FileCheckPattern::isValidVarNameStart(char C) {
@@ -90,31 +129,66 @@
   return C;
 }
 
+static uint64_t doAdd(uint64_t Opl, uint64_t Opr) { return Opl + Opr; }
+static uint64_t doSub(uint64_t Opl, uint64_t Opr) { return Opl - Opr; }
+
 FileCheckNumExpr *
-FileCheckPattern::parseNumericExpression(StringRef Name, StringRef Trailer,
+FileCheckPattern::parseNumericExpression(StringRef Name, bool IsPseudo,
+                                         StringRef Trailer,
                                          const SourceMgr &SM) const {
-  if (!Name.equals("@LINE")) {
+  if (IsPseudo && !Name.equals("@LINE")) {
     SM.PrintMessage(SMLoc::getFromPointer(Name.data()), SourceMgr::DK_Error,
                     "invalid pseudo numeric variable '" + Name + "'");
     return nullptr;
   }
 
-  // Check if this is a supported operation and select function to perform it.
+  // This method is indirectly called from ParsePattern for all numeric
+  // variable definition and uses in the order in which they appear in the
+  // CHECK pattern. For each definition, the pointer to the corresponding AST
+  // class instance is stored in GlobalNumericVariableTable. Therefore the
+  // pointer we get below is for the AST class instance corresponding to the
+  // last definition of the variable before this use.
+  auto VarTableIter = Context->GlobalNumericVariableTable.find(Name);
+  if (VarTableIter == Context->GlobalNumericVariableTable.end()) {
+    SM.PrintMessage(SMLoc::getFromPointer(Name.data()), SourceMgr::DK_Error,
+                    "using undefined numeric variable '" + Name + "'");
+    return nullptr;
+  }
+
+  FileCheckNumVar *Opl = VarTableIter->second;
+
+  // Check if this is a supported operation and selection function to perform
+  // it.
   skipWhitespace(Trailer);
-  if (Trailer.empty())
-    return Context->registerNumExpr(LineNumber);
+  if (Trailer.empty()) {
+    return Context->registerNumExpr(new FileCheckASTBinop(doAdd, Opl, 0));
+  }
   SMLoc OpLoc = SMLoc::getFromPointer(Trailer.data());
   char Operator = popFront(Trailer);
+  binop_eval_t EvalBinop;
+  switch (Operator) {
+  case '+':
+    EvalBinop = doAdd;
+    break;
+  case '-':
+    EvalBinop = doSub;
+    break;
+  default:
+    SM.PrintMessage(OpLoc, SourceMgr::DK_Error,
+                    Twine("unsupported numeric operation '") + Twine(Operator) +
+                        "'");
+    return nullptr;
+  }
 
   // Parse right operand.
   skipWhitespace(Trailer);
   if (Trailer.empty()) {
     SM.PrintMessage(SMLoc::getFromPointer(Trailer.data()), SourceMgr::DK_Error,
-                    "missing operand in numeric expression '" + Trailer + "'");
+                    "missing operand in numeric expression");
     return nullptr;
   }
-  uint64_t Offset;
-  if (Trailer.consumeInteger(10, Offset)) {
+  uint64_t Opr;
+  if (Trailer.consumeInteger(10, Opr)) {
     SM.PrintMessage(SMLoc::getFromPointer(Trailer.data()), SourceMgr::DK_Error,
                     "invalid offset in numeric expression '" + Trailer + "'");
     return nullptr;
@@ -127,21 +201,7 @@
     return nullptr;
   }
 
-  uint64_t Value;
-  switch (Operator) {
-  case '+':
-    Value = LineNumber + Offset;
-    break;
-  case '-':
-    Value = LineNumber - Offset;
-    break;
-  default:
-    SM.PrintMessage(OpLoc, SourceMgr::DK_Error,
-                    Twine("unsupported numeric operation '") + Twine(Operator) +
-                        "'");
-    return nullptr;
-  }
-  return Context->registerNumExpr(Value);
+  return Context->registerNumExpr(new FileCheckASTBinop(EvalBinop, Opl, Opr));
 }
 
 /// Parses the given string into the Pattern.
@@ -158,6 +218,12 @@
   this->LineNumber = LineNumber;
   PatternLoc = SMLoc::getFromPointer(PatternStr.data());
 
+  // Create fake @LINE pseudo variable definition.
+  StringRef LinePseudo = "@LINE";
+  uint64_t LineNumber64 = LineNumber;
+  auto LinePseudoVar = Context->makeNumVar(LinePseudo, LineNumber64);
+  Context->GlobalNumericVariableTable[LinePseudo] = LinePseudoVar;
+
   if (!(Req.NoCanonicalizeWhiteSpace && Req.MatchFullLines))
     // Ignore trailing whitespace.
     while (!PatternStr.empty() &&
@@ -286,21 +352,33 @@
       StringRef Trailer = MatchStr.substr(TrailIdx);
       bool IsVarDef = (VarEndIdx != StringRef::npos);
 
-      if (IsVarDef && (IsPseudo || !Trailer.consume_front(":"))) {
-        SM.PrintMessage(SMLoc::getFromPointer(MatchStr.data()),
-                        SourceMgr::DK_Error,
-                        "invalid name in pattern variable definition");
-        return true;
+      if (IsVarDef) {
+        if (IsPseudo || !Trailer.consume_front(":")) {
+          SM.PrintMessage(SMLoc::getFromPointer(MatchStr.data()),
+                          SourceMgr::DK_Error,
+                          "invalid name in pattern variable definition");
+          return true;
+        }
+
+        // Detect collision between pattern and numeric variable when the former
+        // is created later than the latter.
+        if (Context->GlobalNumericVariableTable.find(Name) !=
+            Context->GlobalNumericVariableTable.end()) {
+          SM.PrintMessage(
+              SMLoc::getFromPointer(MatchStr.data()), SourceMgr::DK_Error,
+              "numeric variable with name '" + Name + "' already exists");
+          return true;
+        }
       }
 
-      if (!IsVarDef && IsPseudo) {
-        NumExpr = parseNumericExpression(Name, Trailer, SM);
+      if (IsNumExpr || (!IsVarDef && IsPseudo)) {
+        NumExpr = parseNumericExpression(Name, IsPseudo, Trailer, SM);
         if (NumExpr == nullptr)
           return true;
         IsNumExpr = true;
       }
 
-      // Handle [[foo]].
+      // Handle variable use: [[foo]] and [[#<foo expr>]].
       if (!IsVarDef) {
         // Handle use of pattern variables that were defined earlier on the
         // same line by emitting a backreference.
@@ -328,6 +406,12 @@
 
       // Handle [[foo:.*]].
       VariableDefs[Name] = CurParen;
+      // Mark pattern variable as defined to detect collision between pattern
+      // and numeric variable in DefineCmdlineVariables when the latter is
+      // created later than the former. We cannot reuse GlobalVariableTable for
+      // that by populating it with an empty string since we would then loose
+      // the ability to detect use of undefined variable in Match().
+      Context->DefinedVariableTable[Name] = true;
       RegExStr += '(';
       ++CurParen;
 
@@ -581,12 +665,18 @@
   return VarIter->second;
 }
 
-template <class... Types>
-FileCheckNumExpr *FileCheckPatternContext::registerNumExpr(Types... Args) {
-  NumExprs.emplace_back(new FileCheckNumExpr(Args...));
+FileCheckNumExpr *
+FileCheckPatternContext::registerNumExpr(FileCheckASTBinop *AST) {
+  NumExprs.emplace_back(new FileCheckNumExpr(AST));
   return NumExprs.back().get();
 }
 
+FileCheckNumVar *FileCheckPatternContext::makeNumVar(StringRef Name,
+                                                     uint64_t Value) {
+  NumVars.emplace_back(new FileCheckNumVar(Name, Value));
+  return NumVars.back().get();
+}
+
 /// Finds the closing sequence of a regex variable usage or definition.
 ///
 /// \p Str has to point in the beginning of the definition (right after the
@@ -1482,7 +1572,7 @@
 
 bool FileCheckPatternContext::defineCmdlineVariables(
     std::vector<std::string> &CmdlineDefines, SourceMgr &SM) {
-  assert(GlobalVariableTable.empty() &&
+  assert(GlobalVariableTable.empty() && GlobalNumericVariableTable.empty() &&
          "Overriding defined variable with command-line variable definitions");
 
   if (CmdlineDefines.empty())
@@ -1500,6 +1590,9 @@
     CmdlineDefsDiag +=
         (Prefix1 + Twine(++I) + Prefix2 + CmdlineDef + "\n").str();
 
+  // Create a buffer with fake command line content in order to display
+  // parsing diagnostic with location information and point to the
+  // global definition with invalid syntax.
   std::unique_ptr<MemoryBuffer> CmdLineDefsDiagBuffer =
       MemoryBuffer::getMemBufferCopy(CmdlineDefsDiag, "Global defines");
   StringRef CmdlineDefsDiagRef = CmdLineDefsDiagBuffer->getBuffer();
@@ -1509,27 +1602,90 @@
   CmdlineDefsDiagRef.split(CmdlineDefsDiagVec, '\n', -1 /*MaxSplit*/,
                            false /*KeepEmpty*/);
   for (StringRef CmdlineDefDiag : CmdlineDefsDiagVec) {
-    unsigned NameStart = CmdlineDefDiag.find(Prefix2) + Prefix2.size();
-    if (CmdlineDefDiag.substr(NameStart).find('=') == StringRef::npos) {
-      SM.PrintMessage(SMLoc::getFromPointer(CmdlineDefDiag.data()),
+    unsigned DefStart = CmdlineDefDiag.find(Prefix2) + Prefix2.size();
+    StringRef CmdlineDef = CmdlineDefDiag.substr(DefStart);
+    if (CmdlineDef.find('=') == StringRef::npos) {
+      SM.PrintMessage(SMLoc::getFromPointer(CmdlineDef.data()),
                       SourceMgr::DK_Error,
                       "Missing equal sign in global definition");
       ErrorFound = true;
       continue;
     }
-    std::pair<StringRef, StringRef> CmdlineNameVal =
-        CmdlineDefDiag.substr(NameStart).split('=');
-    StringRef Name = CmdlineNameVal.first;
-    bool IsPseudo;
-    unsigned TrailIdx;
-    if (FileCheckPattern::parseVariable(Name, IsPseudo, TrailIdx) || IsPseudo ||
-        TrailIdx != Name.size() || Name.empty()) {
-      SM.PrintMessage(SMLoc::getFromPointer(Name.data()), SourceMgr::DK_Error,
-                      "invalid name for variable definition '" + Name + "'");
-      ErrorFound = true;
-      continue;
+
+    // Numeric variable definition.
+    if (CmdlineDef[0] == '#') {
+      bool IsPseudo;
+      unsigned TrailIdx;
+      size_t EqIdx = CmdlineDef.find('=');
+      StringRef CmdlineName = CmdlineDef.substr(1, EqIdx - 1);
+      if (FileCheckPattern::parseVariable(CmdlineName, IsPseudo, TrailIdx) ||
+          IsPseudo || TrailIdx != CmdlineName.size() || CmdlineName.empty()) {
+        SM.PrintMessage(SMLoc::getFromPointer(CmdlineName.data()),
+                        SourceMgr::DK_Error,
+                        "invalid name in numeric variable definition '" +
+                            CmdlineName + "'");
+        ErrorFound = true;
+        continue;
+      }
+
+      // Detect collision between pattern and numeric variable when the latter
+      // is created later than the former.
+      if (DefinedVariableTable.find(CmdlineName) !=
+          DefinedVariableTable.end()) {
+        SM.PrintMessage(
+            SMLoc::getFromPointer(CmdlineName.data()), SourceMgr::DK_Error,
+            "pattern variable with name '" + CmdlineName + "' already exists");
+        ErrorFound = true;
+        continue;
+      }
+
+      StringRef CmdlineVal = CmdlineDef.substr(EqIdx + 1);
+      uint64_t Val;
+      if (CmdlineVal.getAsInteger(10, Val)) {
+        SM.PrintMessage(SMLoc::getFromPointer(CmdlineVal.data()),
+                        SourceMgr::DK_Error,
+                        "invalid value in numeric variable definition '" +
+                            CmdlineVal + "'");
+        ErrorFound = true;
+        continue;
+      }
+      auto NumVarDef = makeNumVar(CmdlineName, Val);
+
+      // Record this variable definition.
+      GlobalNumericVariableTable[CmdlineName] = NumVarDef;
+    } else {
+      // Pattern variable definition.
+      std::pair<StringRef, StringRef> CmdlineNameVal = CmdlineDef.split('=');
+      StringRef Name = CmdlineNameVal.first;
+      bool IsPseudo;
+      unsigned TrailIdx;
+      if (FileCheckPattern::parseVariable(Name, IsPseudo, TrailIdx) ||
+          IsPseudo || TrailIdx != Name.size() || Name.empty()) {
+        SM.PrintMessage(SMLoc::getFromPointer(Name.data()), SourceMgr::DK_Error,
+                        "invalid name in pattern variable definition '" + Name +
+                            "'");
+        ErrorFound = true;
+        continue;
+      }
+
+      // Detect collision between pattern and numeric variable when the former
+      // is created later than the latter.
+      if (GlobalNumericVariableTable.find(Name) !=
+          GlobalNumericVariableTable.end()) {
+        SM.PrintMessage(SMLoc::getFromPointer(Name.data()), SourceMgr::DK_Error,
+                        "numeric variable with name '" + Name +
+                            "' already exists");
+        ErrorFound = true;
+        continue;
+      }
+      GlobalVariableTable.insert(CmdlineNameVal);
+      // Mark pattern variable as defined to detect collision between pattern
+      // and numeric variable in DefineCmdlineVariables when the latter is
+      // created later than the former. We cannot reuse GlobalVariableTable for
+      // that by populating it with an empty string since we would then loose
+      // the ability to detect use of undefined variable in Match().
+      DefinedVariableTable[Name] = true;
     }
-    GlobalVariableTable.insert(CmdlineNameVal);
   }
 
   return ErrorFound;
@@ -1541,6 +1697,14 @@
     if (Var.first()[0] != '$')
       LocalPatternVars.push_back(Var.first());
 
+  // Numeric expression substitution read the value of variable directly, not
+  // via GlobalNUmericVariableTable. Therefore we clear local variable by
+  // clearing their value which will lead to an numeric expression substitution
+  // failure.
+  for (const auto &Var : GlobalNumericVariableTable)
+    if (Var.first()[0] != '$')
+      Var.getValue()->clearValue();
+
   for (const auto &Var : LocalPatternVars)
     GlobalVariableTable.erase(Var);
 }
@@ -1579,7 +1743,10 @@
       ++j;
     }
 
-    if (Req.EnableVarScope)
+    // Do not clear the first region as it's the one before the first
+    // CHECK-LABEL and it would clear variable defined on the command-line
+    // before they get used.
+    if (i != 0 && Req.EnableVarScope)
       PatternContext.clearLocalVars();
 
     for (; i != j; ++i) {
diff --git a/llvm/test/FileCheck/defines.txt b/llvm/test/FileCheck/defines.txt
--- a/llvm/test/FileCheck/defines.txt
+++ b/llvm/test/FileCheck/defines.txt
@@ -11,6 +11,16 @@
 ; RUN: not FileCheck -D10VALUE=10 -input-file %s %s 2>&1 | FileCheck %s --strict-whitespace -check-prefix ERRCLIFMT
 ; RUN: not FileCheck -D@VALUE=10 -input-file %s %s 2>&1 | FileCheck %s --strict-whitespace -check-prefix ERRCLIPSEUDO
 ; RUN: not FileCheck -D'VALUE + 2=10' -input-file %s %s 2>&1 | FileCheck %s --strict-whitespace -check-prefix ERRCLITRAIL
+
+; RUN: FileCheck -D#NUMVAL=12 -check-prefix CHECKNUM -input-file %s %s
+; RUN: not FileCheck -D#NUMVAL=8 -check-prefix CHECKNUM -input-file %s %s 2>&1 | FileCheck %s --strict-whitespace -check-prefix NUMERRMSG
+; RUN: not FileCheck -D#NUMVAL=12 -check-prefix NUMNOT -input-file %s %s 2>&1 | FileCheck %s --strict-whitespace -check-prefix NOT-NUMERRMSG
+; RUN: FileCheck -D#NUMVAL=8 -check-prefixes NUMNOT -input-file %s %s
+; RUN: not FileCheck -D#10VALUE=10 -input-file %s %s 2>&1 | FileCheck %s --strict-whitespace -check-prefix NUMERRCLIFMT
+; RUN: not FileCheck -D#@VALUE=10 -input-file %s %s 2>&1 | FileCheck %s --strict-whitespace -check-prefix NUMERRCLIPSEUDO
+; RUN: not FileCheck -D#'VALUE + 2=10' -input-file %s %s 2>&1 | FileCheck %s --strict-whitespace -check-prefix NUMERRCLITRAIL
+; RUN: not FileCheck -D#VALUE1=3 -D#VALUE2='VALUE1 + 2' -input-file %s %s 2>&1 | FileCheck %s --strict-whitespace -check-prefix NUMERRCLIEXPR
+
 Value = 10
 ; CHECK: Value = [[VALUE]]
 ; NOT-NOT: Value = [[VALUE]]
@@ -35,14 +45,43 @@
 Empty value = @@
 ; EMPTY: Empty value = @[[VALUE]]@
 
-; ERRCLIFMT: Global defines:1:19: error: invalid name for variable definition '10VALUE'
+; ERRCLIFMT: Global defines:1:19: error: invalid name in pattern variable definition '10VALUE'
 ; ERRCLIFMT-NEXT: Global define #1: 10VALUE=10
 ; ERRCLIFMT-NEXT: {{^                  \^$}}
 
-; ERRCLIPSEUDO: Global defines:1:19: error: invalid name for variable definition '@VALUE'
+; ERRCLIPSEUDO: Global defines:1:19: error: invalid name in pattern variable definition '@VALUE'
 ; ERRCLIPSEUDO-NEXT: Global define #1: @VALUE=10
 ; ERRCLIPSEUDO-NEXT: {{^                  \^$}}
 
-; ERRCLITRAIL: Global defines:1:19: error: invalid name for variable definition 'VALUE + 2'
+; ERRCLITRAIL: Global defines:1:19: error: invalid name in pattern variable definition 'VALUE + 2'
 ; ERRCLITRAIL-NEXT: Global define #1: VALUE + 2=10
 ; ERRCLITRAIL-NEXT: {{^                  \^$}}
+
+Numeric value #2 = 12
+; CHECKNUM: Numeric value #2 = [[#NUMVAL]]
+; NUMNOT-NOT: Numeric value #2 = [[#NUMVAL]]
+
+; NUMERRMSG: defines.txt:[[#@LINE-3]]:13: error: CHECKNUM: expected string not found in input
+; NUMERRMSG: defines.txt:1:1: note: scanning from here
+; NUMERRMSG: defines.txt:1:1: note: with numeric expression "NUMVAL" equal to "8"
+; NUMERRMSG: defines.txt:[[#@LINE-7]]:1: note: possible intended match here
+
+; NOT-NUMERRMSG: defines.txt:[[#@LINE-7]]:15: error: {{NUMNOT}}-NOT: excluded string found in input
+; NOT-NUMERRMSG: defines.txt:[[#@LINE-10]]:1: note: found here
+; NOT-NUMERRMSG: defines.txt:[[#@LINE-11]]:1: note: with numeric expression "NUMVAL" equal to "12"
+
+; NUMERRCLIFMT: Global defines:1:20: error: invalid name in numeric variable definition '10VALUE'
+; NUMERRCLIFMT-NEXT: Global define #1: #10VALUE=10
+; NUMERRCLIFMT-NEXT: {{^                   \^$}}
+
+; NUMERRCLIPSEUDO: Global defines:1:20: error: invalid name in numeric variable definition '@VALUE'
+; NUMERRCLIPSEUDO-NEXT: Global define #1: #@VALUE=10
+; NUMERRCLIPSEUDO-NEXT: {{^                   \^$}}
+
+; NUMERRCLITRAIL: Global defines:1:20: error: invalid name in numeric variable definition 'VALUE + 2'
+; NUMERRCLITRAIL-NEXT: Global define #1: #VALUE + 2=10
+; NUMERRCLITRAIL-NEXT: {{^                   \^$}}
+
+; NUMERRCLIEXPR: Global defines:2:27: error: invalid value in numeric variable definition 'VALUE1 + 2'
+; NUMERRCLIEXPR-NEXT: Global define #2: #VALUE2=VALUE1 + 2
+; NUMERRCLIEXPR-NEXT: {{^                          \^$}}
diff --git a/llvm/test/FileCheck/numeric-expression.txt b/llvm/test/FileCheck/numeric-expression.txt
new file mode 100644
--- /dev/null
+++ b/llvm/test/FileCheck/numeric-expression.txt
@@ -0,0 +1,95 @@
+; RUN: FileCheck -D#VAR1=11 -input-file %s %s
+; RUN: not FileCheck -check-prefix UNDEF-USE -input-file %s %s 2>&1 | FileCheck --strict-whitespace -check-prefix UNDEF-USE-MSG %s
+; RUN: not FileCheck -D#VAR1=11 -check-prefixes CHECK,INVAL-OP -input-file %s %s 2>&1 | FileCheck --strict-whitespace -check-prefix INVAL-OP-MSG %s
+; RUN: not FileCheck -D#VAR1=11 -D#NUMVAR=42 -check-prefixes CONFLICT,CONFLICT1 -input-file %s %s 2>&1 | FileCheck --strict-whitespace -check-prefix CLI-INPUT-PAT-CONFLICT %s
+; RUN: not FileCheck -D#VAR1=11 -D#NUMVAR=42 -DNUMVAR=foobar -check-prefix CONFLICT -input-file %s %s 2>&1 | FileCheck --strict-whitespace -check-prefix CLI-CLI-PAT-CONFLICT %s
+; RUN: not FileCheck -D#VAR1=11 -DPATVAR=foobar -D#PATVAR=42 -check-prefix CONFLICT -input-file %s %s 2>&1 | FileCheck --strict-whitespace -check-prefix CLI-CLI-NUM-CONFLICT %s
+
+
+; We ensure we attemt to match all lines with digits by using CHECK-NEXT
+; directives for the checks to ensure each line of input is covered.
+
+
+; Numeric expressions using variables defined on the command-line without
+; spaces
+USE NO SPC
+11
+12
+10
+; CHECK-LABEL: USE NO SPC
+; CHECK-NEXT: [[#VAR1]]
+; CHECK-NEXT: [[#VAR1+1]]
+; CHECK-NEXT: [[#VAR1-1]]
+
+
+; Numeric expressions using variables defined on the command-line in alternate
+; spacing
+USE ALT SPC
+11
+11
+12
+12
+12
+12
+10
+10
+10
+10
+; CHECK-LABEL: USE ALT SPC
+; CHECK-NEXT: [[# VAR1]]
+; CHECK-NEXT: [[# VAR1 ]]
+; CHECK-NEXT: [[# VAR1+1]]
+; CHECK-NEXT: [[# VAR1 +1]]
+; CHECK-NEXT: [[# VAR1 + 1]]
+; CHECK-NEXT: [[# VAR1 + 1 ]]
+; CHECK-NEXT: [[# VAR1-1]]
+; CHECK-NEXT: [[# VAR1 -1]]
+; CHECK-NEXT: [[# VAR1 - 1]]
+; CHECK-NEXT: [[# VAR1 - 1 ]]
+
+
+; Numeric expressions using variables defined on the command-line and an
+; immediate interpreted as an unsigned value
+; Note: 9223372036854775819 = 0x8000000000000000 + 11
+;       9223372036854775808 = 0x8000000000000000
+USE UNSIGNED IMM
+9223372036854775819
+; CHECK-LABEL: USE UNSIGNED IMM
+; CHECK-NEXT: [[#VAR1+9223372036854775808]]
+
+
+; Numeric expression using undefined variable
+UNDEF VAR USE
+UNDEFVAR: 11
+; UNDEF-USE-LABEL: UNDEF VAR USE
+; UNDEF-USE-NEXT: UNDEFVAR: [[#UNDEFVAR]]
+; UNDEF-USE-MSG: numeric-expression.txt:[[#@LINE-1]]:32: error: using undefined numeric variable 'UNDEFVAR'
+; UNDEF-USE-MSG-NEXT: ; {{U}}NDEF-USE-NEXT: UNDEFVAR: {{\[\[#UNDEFVAR\]\]}}
+; UNDEF-USE-MSG-NEXT: {{^                               \^$}}
+
+
+; Numeric expression with unsupported operator
+INVALID OPERATOR
+VAR1*2: 22
+; INVAL-OP-LABEL: INVALID OPERATOR
+; INVAL-OP-NEXT: VAR1*2: [[#VAR1*2]]
+; INVAL-OP-MSG: numeric-expression.txt:[[#@LINE-1]]:33: error: unsupported numeric operation '*'
+; INVAL-OP-MSG-NEXT: ; {{I}}NVAL-OP-NEXT: VAR1*2: {{\[\[#VAR1\*2\]\]}}
+; INVAL-OP-MSG-NEXT: {{^                                \^$}}
+
+
+; Name conflict between Numeric variable definition and pattern variable
+; definition
+PATVAR NUMVAR CONFLICT
+foobar
+; CONFLICT-LABEL: PATVAR NUMVAR CONFLICT
+; CONFLICT1-NEXT: [[NUMVAR:foo.*]]
+; CLI-INPUT-PAT-CONFLICT: numeric-expression.txt:[[#@LINE-1]]:21: error: numeric variable with name 'NUMVAR' already exists
+; CLI-INPUT-PAT-CONFLICT-NEXT: ; {{C}}ONFLICT1-NEXT: {{\[\[NUMVAR:foo\.\*\]\]}}
+; CLI-INPUT-PAT-CONFLICT-NEXT: {{^                    \^$}}
+; CLI-CLI-PAT-CONFLICT: Global defines:3:19: error: numeric variable with name 'NUMVAR' already exists
+; CLI-CLI-PAT-CONFLICT-NEXT: Global define #3: NUMVAR=foobar
+; CLI-CLI-PAT-CONFLICT-NEXT: {{^                  \^$}}
+; CLI-CLI-NUM-CONFLICT: Global defines:3:20: error: pattern variable with name 'PATVAR' already exists
+; CLI-CLI-NUM-CONFLICT-NEXT: Global define #3: #PATVAR=42
+; CLI-CLI-NUM-CONFLICT-NEXT: {{^                   \^$}}
diff --git a/llvm/test/FileCheck/regex-scope.txt b/llvm/test/FileCheck/regex-scope.txt
deleted file mode 100644
--- a/llvm/test/FileCheck/regex-scope.txt
+++ /dev/null
@@ -1,23 +0,0 @@
-// RUN: FileCheck -input-file %s %s
-// RUN: FileCheck -check-prefixes CHECK,GLOBAL -input-file %s %s
-// RUN: FileCheck -check-prefixes CHECK,LOCAL -input-file %s %s
-// RUN: FileCheck -check-prefixes CHECK,GLOBAL --enable-var-scope -input-file %s %s
-// RUN: not FileCheck -check-prefixes CHECK,LOCAL --enable-var-scope -input-file %s %s
-
-local
-global
-; CHECK: [[LOCAL:loc.*]]
-; CHECK: [[$GLOBAL:glo.*]]
-
-local2
-global2
-; CHECK: [[LOCAL]]2
-; CHECK: [[$GLOBAL]]2
-
-barrier:
-; CHECK-LABEL: barrier
-
-local3
-global3
-; LOCAL: [[LOCAL]]3
-; GLOBAL: [[$GLOBAL]]3
diff --git a/llvm/test/FileCheck/var-scope.txt b/llvm/test/FileCheck/var-scope.txt
new file mode 100644
--- /dev/null
+++ b/llvm/test/FileCheck/var-scope.txt
@@ -0,0 +1,27 @@
+// RUN: FileCheck -D#LOCNUM=1 -D'#$GLOBNUM=1' -input-file %s %s
+// RUN: FileCheck -D#LOCNUM=1 -D'#$GLOBNUM=1' -check-prefixes CHECK,GLOBAL -input-file %s %s
+// RUN: FileCheck -D#LOCNUM=1 -D'#$GLOBNUM=1' -check-prefixes CHECK,LOCAL3 -input-file %s %s
+// RUN: FileCheck -D#LOCNUM=1 -D'#$GLOBNUM=1' -check-prefixes CHECK,GLOBAL --enable-var-scope -input-file %s %s
+// RUN: not FileCheck -D#LOCNUM=1 -D#$GLOBNUM=1 -check-prefixes CHECK,LOCAL1 --enable-var-scope -input-file %s %s
+// RUN: not FileCheck -D#LOCNUM=1 -D#$GLOBNUM=1 -check-prefixes CHECK,LOCAL2 --enable-var-scope -input-file %s %s
+// RUN: not FileCheck -D#LOCNUM=1 -D#$GLOBNUM=1 -check-prefixes CHECK,LOCAL3 --enable-var-scope -input-file %s %s
+
+local1
+global1
+; CHECK: [[LOCAL:loc[^[:digit:]]*]][[#LOCNUM]]
+; CHECK: [[$GLOBAL:glo[^[:digit:]]*]][[#$GLOBNUM]]
+
+local2
+global2
+; CHECK: [[LOCAL]][[#LOCNUM+1]]
+; CHECK: [[$GLOBAL]][[#$GLOBNUM+1]]
+
+barrier:
+; CHECK-LABEL: barrier
+
+local3
+global3
+; LOCAL1: [[LOCAL]]3
+; LOCAL2: local[[#LOCNUM+2]]
+; LOCAL3: [[LOCAL]][[#LOCNUM+2]]
+; GLOBAL: [[$GLOBAL]][[#$GLOBNUM+2]]
diff --git a/llvm/test/FileCheck/verbose.txt b/llvm/test/FileCheck/verbose.txt
--- a/llvm/test/FileCheck/verbose.txt
+++ b/llvm/test/FileCheck/verbose.txt
@@ -1,6 +1,6 @@
-; RUN: FileCheck -input-file %s %s 2>&1 | FileCheck -check-prefix QUIET --allow-empty %s
-; RUN: FileCheck -v -input-file %s %s 2>&1 | FileCheck -check-prefix V %s
-; RUN: FileCheck -vv -input-file %s %s 2>&1 | FileCheck -check-prefixes V,VV %s
+; RUN: FileCheck -D#NUMVAR=42 -input-file %s %s 2>&1 | FileCheck -check-prefix QUIET --allow-empty %s
+; RUN: FileCheck -v -D#NUMVAR=42 -input-file %s %s 2>&1 | FileCheck --strict-whitespace -check-prefix V %s
+; RUN: FileCheck -vv -D#NUMVAR=42 -input-file %s %s 2>&1 | FileCheck --strict-whitespace -check-prefixes V,VV %s
 
 foo
 bar
@@ -29,6 +29,39 @@
 VV-NEXT: {{^}}bar{{$}}
 VV-NEXT: {{^}}^{{$}}
 
+NUMVAR:42
+NUMVAR - 1:41
+CHECK: NUMVAR:[[#NUMVAR]]
+CHECK-NOT: [[#NUMVAR + 1]]
+CHECK-NEXT: NUMVAR - 1:[[#NUMVAR - 1]]
+
+V:      verbose.txt:[[#@LINE-4]]:8: remark: {{C}}HECK: expected string found in input
+V-NEXT: {{C}}HECK: {{NUMVAR:[[][[]#NUMVAR[]][]]$}}
+V-NEXT: {{^       \^$}}
+V-NEXT: verbose.txt:[[#@LINE-9]]:1: note: found here
+V-NEXT: {{^}}NUMVAR:42{{$}}
+V-NEXT: {{^}}^~~~~~~~~{{$}}
+V-NEXT: verbose.txt:[[#@LINE-12]]:1: note: with numeric expression "NUMVAR" equal to "42"
+V-NEXT: {{^}}NUMVAR:42{{$}}
+V-NEXT: {{^}}^~~~~~~~~{{$}}
+
+V-NEXT: verbose.txt:[[#@LINE-12]]:13: remark: {{C}}HECK-NEXT: expected string found in input
+V-NEXT: {{C}}HECK-NEXT: {{NUMVAR - 1:[[][[]#NUMVAR - 1[]][]]$}}
+V-NEXT: {{^            \^$}}
+V-NEXT: verbose.txt:[[#@LINE-18]]:1: note: found here
+V-NEXT: {{^}}NUMVAR - 1:41{{$}}
+V-NEXT: {{^}}^~~~~~~~~~~~~{{$}}
+V-NEXT: verbose.txt:[[#@LINE-21]]:1: note: with numeric expression "NUMVAR - 1" equal to "41"
+V-NEXT: {{^}}NUMVAR - 1:41{{$}}
+V-NEXT: {{^}}^~~~~~~~~~~~~{{$}}
+
+VV-NEXT: verbose.txt:[[#@LINE-23]]:12: remark: {{C}}HECK-NOT: excluded string not found in input
+VV-NEXT: {{C}}HECK-NOT: {{[[][[]#NUMVAR [+] 1[]][]]$}}
+VV-NEXT: {{^           \^$}}
+VV-NEXT: verbose.txt:[[#@LINE-28]]:1: note: scanning from here
+VV-NEXT: {{^}}NUMVAR - 1:41{{$}}
+VV-NEXT: {{^}}^{{$}}
+
 before empty
 
 after empty
@@ -99,7 +132,7 @@
 
 VV-NEXT: verbose.txt:[[@LINE-9]]:19: remark: implicit EOF: expected string found in input
 VV-NEXT: {{C}}HECK-NOT: {{[{][{]z[}][}]yx$}}
-VV-NEXT:   {{^                 \^$}}
+VV-NEXT:   {{^                  \^$}}
 VV-NEXT: verbose.txt:[[@LINE+13]]:1: note: found here
 VV-NOT:  {{.}}
 VV:      {{^\^$}}
diff --git a/llvm/unittests/Support/FileCheckTest.cpp b/llvm/unittests/Support/FileCheckTest.cpp
--- a/llvm/unittests/Support/FileCheckTest.cpp
+++ b/llvm/unittests/Support/FileCheckTest.cpp
@@ -14,6 +14,49 @@
 
 class FileCheckTest : public ::testing::Test {};
 
+TEST_F(FileCheckTest, NumVarValueGetClearSet) {
+  FileCheckNumVar FooVar = FileCheckNumVar("FOO", 42);
+
+  // Defined variable: getValue returns a value, setValue fails.
+  llvm::Optional<uint64_t> Value = FooVar.getValue();
+  EXPECT_TRUE(Value);
+  EXPECT_EQ((uint64_t)42, *Value);
+  EXPECT_TRUE(FooVar.setValue((uint64_t)43));
+
+  // Clearing variable: getValue fails, clearValue again fails.
+  EXPECT_FALSE(FooVar.clearValue());
+  Value = FooVar.getValue();
+  EXPECT_FALSE(Value);
+  EXPECT_TRUE(FooVar.clearValue());
+
+  // Undefined variable: setValue works, getValue returns value set.
+  EXPECT_FALSE(FooVar.setValue((uint64_t)43));
+  Value = FooVar.getValue();
+  EXPECT_TRUE(Value);
+  EXPECT_EQ((uint64_t)43, *Value);
+}
+
+uint64_t doAdd(uint64_t OpL, uint64_t OpR) { return OpL + OpR; }
+
+TEST_F(FileCheckTest, BinopEvalUndef) {
+  auto FooVar = new FileCheckNumVar("FOO", 42);
+  auto Binop = new FileCheckASTBinop(doAdd, FooVar, 18);
+
+  // Defined variable: eval returns right value, no undef variable returned.
+  llvm::Optional<uint64_t> Value = Binop->eval();
+  EXPECT_TRUE(Value);
+  EXPECT_EQ((uint64_t)60, *Value);
+  StringRef UndefVar = Binop->getUndefVarName();
+  EXPECT_EQ("", UndefVar);
+
+  // Undefined variable: eval fails, undef variable returned.
+  FooVar->clearValue();
+  Value = Binop->eval();
+  EXPECT_FALSE(Value);
+  UndefVar = Binop->getUndefVarName();
+  EXPECT_EQ("FOO", UndefVar);
+}
+
 TEST_F(FileCheckTest, ValidVarNameStart) {
   EXPECT_TRUE(FileCheckPattern::isValidVarNameStart('a'));
   EXPECT_TRUE(FileCheckPattern::isValidVarNameStart('G'));
@@ -93,11 +136,21 @@
 class ExprTester {
 private:
   SourceMgr SM;
+  struct FileCheckRequest Req;
   FileCheckPatternContext Context;
   FileCheckPattern P = FileCheckPattern(Check::CheckPlain, &Context);
 
 public:
+  ExprTester() {
+    std::vector<std::string> GlobalDefines;
+    GlobalDefines.emplace_back(std::string("#FOO=42"));
+    Context.defineCmdlineVariables(GlobalDefines, SM);
+    // Call ParsePattern to have @LINE defined.
+    P.ParsePattern("N/A", "CHECK", SM, 1, Req);
+  }
+
   bool parseExpect(std::string &VarName, std::string &Trailer) {
+    bool IsPseudo = VarName[0] == '@';
     StringRef NameTrailer = StringRef(VarName + Trailer);
     std::unique_ptr<MemoryBuffer> Buffer =
         MemoryBuffer::getMemBufferCopy(NameTrailer, "TestBuffer");
@@ -105,7 +158,8 @@
     SM.AddNewSourceBuffer(std::move(Buffer), SMLoc());
     StringRef VarNameRef = NameTrailerRef.substr(0, VarName.size());
     StringRef TrailerRef = NameTrailerRef.substr(VarName.size());
-    return P.parseNumericExpression(VarNameRef, TrailerRef, SM) == nullptr;
+    return P.parseNumericExpression(VarNameRef, IsPseudo, TrailerRef, SM) ==
+           nullptr;
   }
 };
 
@@ -121,6 +175,14 @@
   Trailer = "";
   EXPECT_FALSE(Tester.parseExpect(VarName, Trailer));
 
+  // Defined variable
+  VarName = "FOO";
+  EXPECT_FALSE(Tester.parseExpect(VarName, Trailer));
+
+  // Undefined variable
+  VarName = "UNDEF";
+  EXPECT_TRUE(Tester.parseExpect(VarName, Trailer));
+
   // Wrong Pseudovar.
   VarName = "@FOO";
   EXPECT_TRUE(Tester.parseExpect(VarName, Trailer));
@@ -153,15 +215,24 @@
   GlobalDefines.emplace_back(std::string("FOO=BAR"));
   Context.defineCmdlineVariables(GlobalDefines, SM);
 
+  // Substitution of undefined pattern variable fails.
   FileCheckPatternSubst Subst = FileCheckPatternSubst(&Context, "VAR404", 42);
   EXPECT_FALSE(Subst.getSubstitute());
 
-  FileCheckNumExpr NumExpr = FileCheckNumExpr(42);
+  // Substitution of defined numeric variable returns the right value.
+  auto LineVar = new FileCheckNumVar("@LINE", 42);
+  auto Binop = new FileCheckASTBinop(doAdd, LineVar, 0);
+  FileCheckNumExpr NumExpr = FileCheckNumExpr(Binop);
   Subst = FileCheckPatternSubst(&Context, "@LINE", &NumExpr, 12);
   llvm::Optional<std::string> Value = Subst.getSubstitute();
   EXPECT_TRUE(Value);
   EXPECT_EQ("42", *Value);
 
+  // Substitution of undefined numeric variable fails.
+  LineVar->clearValue();
+  EXPECT_FALSE(Subst.getSubstitute());
+
+  // Substitution of defined pattern variable returns the right value.
   FileCheckPattern P = FileCheckPattern(Check::CheckPlain, &Context);
   Subst = FileCheckPatternSubst(&Context, "FOO", 42);
   Value = Subst.getSubstitute();
@@ -176,18 +247,32 @@
   GlobalDefines.emplace_back(std::string("FOO=BAR"));
   Context.defineCmdlineVariables(GlobalDefines, SM);
 
+  // Undef var in pattern variable substitution with undefined variable returns
+  // the variable.
   FileCheckPatternSubst Subst = FileCheckPatternSubst(&Context, "VAR404", 42);
   StringRef UndefVar = Subst.getUndefVarName();
   EXPECT_EQ("VAR404", UndefVar);
 
-  FileCheckNumExpr NumExpr = FileCheckNumExpr(42);
-  Subst = FileCheckPatternSubst(&Context, "@LINE", &NumExpr, 12);
+  // Undef var in pattern variable substitution with defined variable is empty.
+  Subst = FileCheckPatternSubst(&Context, "FOO", 42);
   UndefVar = Subst.getUndefVarName();
   EXPECT_EQ("", UndefVar);
 
-  Subst = FileCheckPatternSubst(&Context, "FOO", 42);
+  // Undef var in numeric expression substitution with defined variable is
+  // empty.
+  auto LineVar = new FileCheckNumVar("@LINE", 42);
+  auto Binop = new FileCheckASTBinop(doAdd, LineVar, 0);
+  FileCheckNumExpr NumExpr = FileCheckNumExpr(Binop);
+  Subst = FileCheckPatternSubst(&Context, "@LINE", &NumExpr, 12);
   UndefVar = Subst.getUndefVarName();
   EXPECT_EQ("", UndefVar);
+
+  // Undef var in valid numeric expression substitution is empty.
+  // Undef var in numeric expression substitution with undefined variable
+  // returns the variable.
+  LineVar->clearValue();
+  UndefVar = Subst.getUndefVarName();
+  EXPECT_EQ("@LINE", UndefVar);
 }
 
 TEST_F(FileCheckTest, FileCheckContext) {