diff --git a/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp b/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
--- a/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
@@ -58,6 +58,7 @@
 #include "SuspiciousMemoryComparisonCheck.h"
 #include "SuspiciousMemsetUsageCheck.h"
 #include "SuspiciousMissingCommaCheck.h"
+#include "SuspiciousReallocUsageCheck.h"
 #include "SuspiciousSemicolonCheck.h"
 #include "SuspiciousStringCompareCheck.h"
 #include "SwappedArgumentsCheck.h"
@@ -173,6 +174,8 @@
         "bugprone-suspicious-memset-usage");
     CheckFactories.registerCheck<SuspiciousMissingCommaCheck>(
         "bugprone-suspicious-missing-comma");
+    CheckFactories.registerCheck<SuspiciousReallocUsageCheck>(
+        "bugprone-suspicious-realloc-usage");
     CheckFactories.registerCheck<SuspiciousSemicolonCheck>(
         "bugprone-suspicious-semicolon");
     CheckFactories.registerCheck<SuspiciousStringCompareCheck>(
diff --git a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
--- a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
@@ -54,6 +54,7 @@
   SuspiciousMemoryComparisonCheck.cpp
   SuspiciousMemsetUsageCheck.cpp
   SuspiciousMissingCommaCheck.cpp
+  SuspiciousReallocUsageCheck.cpp
   SuspiciousSemicolonCheck.cpp
   SuspiciousStringCompareCheck.cpp
   SwappedArgumentsCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/bugprone/SuspiciousReallocUsageCheck.h b/clang-tools-extra/clang-tidy/bugprone/SuspiciousReallocUsageCheck.h
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/bugprone/SuspiciousReallocUsageCheck.h
@@ -0,0 +1,36 @@
+//===--- SuspiciousReallocUsageCheck.h - clang-tidy -------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_SUSPICIOUSREALLOCUSAGECHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_SUSPICIOUSREALLOCUSAGECHECK_H
+
+#include "../ClangTidyCheck.h"
+
+namespace clang {
+namespace tidy {
+namespace bugprone {
+
+/// Finds usages of ``realloc`` where the return value is assigned to the same
+/// variable as passed to the first argument.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/bugprone/suspicious-realloc-usage.html
+class SuspiciousReallocUsageCheck : public ClangTidyCheck {
+public:
+  SuspiciousReallocUsageCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace bugprone
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_SUSPICIOUSREALLOCUSAGECHECK_H
diff --git a/clang-tools-extra/clang-tidy/bugprone/SuspiciousReallocUsageCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/SuspiciousReallocUsageCheck.cpp
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/bugprone/SuspiciousReallocUsageCheck.cpp
@@ -0,0 +1,95 @@
+//===--- SuspiciousReallocUsageCheck.cpp - clang-tidy----------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "SuspiciousReallocUsageCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/DeclVisitor.h"
+#include "clang/AST/StmtVisitor.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+
+using namespace clang::ast_matchers;
+using namespace clang;
+
+namespace {
+class IsSamePtrExpr : public clang::StmtVisitor<IsSamePtrExpr, bool> /*,
+                         public clang::DeclVisitor<IsSamePtrExpr, bool>*/
+{
+  /// The other expression to compare with.
+  /// This variable is used to pass the data from a \c check function to any of
+  /// the visit functions. Every visit function starts by converting \c OtherE
+  /// to the current type and store it locally, and do not use \c OtherE later.
+  const Expr *OtherE = nullptr;
+
+public:
+  bool VisitDeclRefExpr(const DeclRefExpr *E1) {
+    const auto *E2 = dyn_cast<DeclRefExpr>(OtherE);
+    if (!E2)
+      return false;
+    const Decl *D1 = E1->getDecl()->getCanonicalDecl();
+    return isa<VarDecl, FieldDecl>(D1) &&
+           D1 == E2->getDecl()->getCanonicalDecl();
+  }
+
+  bool VisitMemberExpr(const MemberExpr *E1) {
+    const auto *E2 = dyn_cast<MemberExpr>(OtherE);
+    if (!E2)
+      return false;
+    if (!check(E1->getBase(), E2->getBase()))
+      return false;
+    DeclAccessPair FD = E1->getFoundDecl();
+    return isa<FieldDecl>(FD.getDecl()) && FD == E2->getFoundDecl();
+  }
+
+  bool check(const Expr *E1, const Expr *E2) {
+    E1 = E1->IgnoreParenCasts();
+    E2 = E2->IgnoreParenCasts();
+    OtherE = E2;
+    return Visit(const_cast<Expr *>(E1));
+  }
+};
+} // namespace
+
+namespace clang {
+namespace tidy {
+namespace bugprone {
+
+void SuspiciousReallocUsageCheck::registerMatchers(MatchFinder *Finder) {
+  // void *realloc(void *ptr, size_t size);
+  auto ReallocDecl =
+      functionDecl(hasName("::realloc"), parameterCountIs(2),
+                   hasParameter(0, hasType(pointerType(pointee(voidType())))),
+                   hasParameter(1, hasType(isInteger())));
+
+  auto ReallocCall =
+      callExpr(callee(ReallocDecl), hasArgument(0, expr().bind("ptr_input")))
+          .bind("call");
+  Finder->addMatcher(binaryOperator(hasOperatorName("="),
+                                    hasLHS(expr().bind("ptr_result")),
+                                    hasRHS(ignoringParenCasts(ReallocCall))),
+                     this);
+}
+
+void SuspiciousReallocUsageCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  const auto *Call = Result.Nodes.getNodeAs<CallExpr>("call");
+  if (!Call)
+    return;
+  const auto *PtrInputExpr = Result.Nodes.getNodeAs<Expr>("ptr_input");
+  const auto *PtrResultExpr = Result.Nodes.getNodeAs<Expr>("ptr_result");
+  if (!PtrInputExpr || !PtrResultExpr)
+    return;
+  if (!IsSamePtrExpr().check(PtrInputExpr, PtrResultExpr))
+    return;
+  diag(Call->getBeginLoc(),
+       "memory block passed to 'realloc' may leak if 'realloc' fails");
+}
+
+} // namespace bugprone
+} // namespace tidy
+} // namespace clang
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -99,6 +99,12 @@
 New checks
 ^^^^^^^^^^
 
+- New :doc:`bugprone-suspicious-realloc-usage
+  <clang-tidy/checks/bugprone/suspicious-realloc-usage>` check.
+
+  Finds usages of ``realloc`` where the return value is assigned to the
+  same expression as passed to the first argument.
+
 - New :doc:`cppcoreguidelines-avoid-const-or-ref-data-members
   <clang-tidy/checks/cppcoreguidelines/avoid-const-or-ref-data-members>` check.
 
diff --git a/clang-tools-extra/docs/clang-tidy/checks/bugprone/suspicious-realloc-usage.rst b/clang-tools-extra/docs/clang-tidy/checks/bugprone/suspicious-realloc-usage.rst
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/docs/clang-tidy/checks/bugprone/suspicious-realloc-usage.rst
@@ -0,0 +1,31 @@
+.. title:: clang-tidy - bugprone-suspicious-realloc-usage
+
+bugprone-suspicious-realloc-usage
+=================================
+
+This check finds usages of ``realloc`` where the return value is assigned to the
+same expression as passed to the first argument:
+``p = realloc(p, size);``
+The problem with this construct is that if ``realloc`` fails it returns a
+null pointer but does not deallocate the original memory. The original
+memory block is not available any more for the program to use or free (unless
+another variable is pointing to it).
+
+The pointer expression can be a variable or a field member of a data structure,
+but can not contain function calls or unresolved types.
+
+Examples:
+
+.. code-block:: c++
+
+  struct A {
+    void *p;
+  };
+
+  A &getA();
+
+  void foo(void *p, A *a, int new_size) {
+    p = realloc(p, new_size); // warning: memory block passed to 'realloc' may leak if 'realloc' fails
+    a->p = realloc(a->p, new_size); // warning: memory block passed to 'realloc' may leak if 'realloc' fails
+    getA().p = realloc(getA().p, new_size); // no warning
+  }
diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst
--- a/clang-tools-extra/docs/clang-tidy/checks/list.rst
+++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst
@@ -124,6 +124,7 @@
    `bugprone-suspicious-memory-comparison <bugprone/suspicious-memory-comparison.html>`_,
    `bugprone-suspicious-memset-usage <bugprone/suspicious-memset-usage.html>`_, "Yes"
    `bugprone-suspicious-missing-comma <bugprone/suspicious-missing-comma.html>`_,
+   `bugprone-suspicious-realloc-usage <bugprone/suspicious-realloc-usage.html>`_,
    `bugprone-suspicious-semicolon <bugprone/suspicious-semicolon.html>`_, "Yes"
    `bugprone-suspicious-string-compare <bugprone/suspicious-string-compare.html>`_, "Yes"
    `bugprone-swapped-arguments <bugprone/swapped-arguments.html>`_, "Yes"
diff --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone/suspicious-realloc-usage.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone/suspicious-realloc-usage.cpp
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone/suspicious-realloc-usage.cpp
@@ -0,0 +1,79 @@
+// RUN: %check_clang_tidy %s bugprone-suspicious-realloc-usage %t
+
+void *realloc(void *, __SIZE_TYPE__);
+
+namespace std {
+  using ::realloc;
+}
+
+namespace n1 {
+  void *p;
+}
+
+namespace n2 {
+  void *p;
+}
+
+struct P {
+  void *p;
+  void *q;
+  P *pp;
+  void *&f();
+};
+
+struct P1 {
+  static void *p;
+  static void *q;
+};
+
+template<class>
+struct P2 {
+  static void *p;
+  static void *q;
+};
+
+template<class A, class B>
+void templ(void *p) {
+  A::p = realloc(A::p, 10);
+  // CHECK-MESSAGES: :[[@LINE-1]]:10: warning: memory block passed to 'realloc' may leak if 'realloc' fails [bugprone-suspicious-realloc-usage]
+  p = realloc(A::p, 10);
+  A::q = realloc(A::p, 10);
+  A::p = realloc(B::p, 10);
+  P2<A>::p = realloc(P2<A>::p, 1);
+  // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: memory block passed to 'realloc' may leak if 'realloc' fails [bugprone-suspicious-realloc-usage]
+  P2<A>::p = realloc(P2<B>::p, 1);
+}
+
+void *&getPtr();
+P &getP();
+
+void foo(void *p, P *p1, int *pi) {
+  p = realloc(p, 111);
+  // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: memory block passed to 'realloc' may leak if 'realloc' fails [bugprone-suspicious-realloc-usage]
+
+  p = std::realloc(p, sizeof(int));
+  // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: memory block passed to 'realloc' may leak if 'realloc' fails [bugprone-suspicious-realloc-usage]
+
+  p1->p = realloc(p1->p, 10);
+  // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: memory block passed to 'realloc' may leak if 'realloc' fails [bugprone-suspicious-realloc-usage]
+
+  p1->pp->p = realloc(p1->pp->p, 10);
+  // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: memory block passed to 'realloc' may leak if 'realloc' fails [bugprone-suspicious-realloc-usage]
+
+  pi = (int*)realloc(pi, 10);
+  // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: memory block passed to 'realloc' may leak if 'realloc' fails [bugprone-suspicious-realloc-usage]
+
+  templ<P1, P2<int>>(p);
+}
+
+void no_warn(void *p, P *p1, P *p2) {
+  void *q = realloc(p, 10);
+  q = realloc(p, 10);
+  p1->q = realloc(p1->p, 10);
+  p2->p = realloc(p1->p, 20);
+  n1::p = realloc(n2::p, 30);
+  p1->pp->p = realloc(p1->p, 10);
+  getPtr() = realloc(getPtr(), 30);
+  getP().p = realloc(getP().p, 20);
+  p1->f() = realloc(p1->f(), 30);
+}