diff --git a/src/libs/utils/reloadpromptutils.cpp b/src/libs/utils/reloadpromptutils.cpp
index 8eec9e92e1b..798a4876a70 100644
--- a/src/libs/utils/reloadpromptutils.cpp
+++ b/src/libs/utils/reloadpromptutils.cpp
@@ -35,6 +35,7 @@ namespace Utils {
 
 QTCREATOR_UTILS_EXPORT ReloadPromptAnswer reloadPrompt(const FileName &fileName,
                                                        bool modified,
+                                                       bool enableDiffOption,
                                                        QWidget *parent)
 {
 
@@ -50,12 +51,13 @@ QTCREATOR_UTILS_EXPORT ReloadPromptAnswer reloadPrompt(const FileName &fileName,
                 "The file <i>%1</i> has changed outside Qt Creator. Do you want to reload it?");
     }
     msg = msg.arg(fileName.fileName());
-    return reloadPrompt(title, msg, fileName.toUserOutput(), parent);
+    return reloadPrompt(title, msg, fileName.toUserOutput(), enableDiffOption, parent);
 }
 
 QTCREATOR_UTILS_EXPORT ReloadPromptAnswer reloadPrompt(const QString &title,
                                                        const QString &prompt,
                                                        const QString &details,
+                                                       bool enableDiffOption,
                                                        QWidget *parent)
 {
     QMessageBox msg(parent);
@@ -69,7 +71,19 @@ QTCREATOR_UTILS_EXPORT ReloadPromptAnswer reloadPrompt(const QString &title,
     msg.button(QMessageBox::Close)->setText(QCoreApplication::translate("Utils::reloadPrompt",
                                                                         "&Close"));
 
-    switch (msg.exec()) {
+    QPushButton *diffButton = nullptr;
+    if (enableDiffOption) {
+        diffButton = msg.addButton(QCoreApplication::translate(
+                                   "Utils::reloadPrompt", "No to All && &Diff"),
+                                   QMessageBox::NoRole);
+    }
+
+    const int result = msg.exec();
+
+    if (msg.clickedButton() == diffButton)
+        return ReloadNoneAndDiff;
+
+    switch (result) {
     case QMessageBox::Yes:
         return  ReloadCurrent;
     case QMessageBox::YesToAll:
diff --git a/src/libs/utils/reloadpromptutils.h b/src/libs/utils/reloadpromptutils.h
index b01bd25b53b..8991d52b59b 100644
--- a/src/libs/utils/reloadpromptutils.h
+++ b/src/libs/utils/reloadpromptutils.h
@@ -40,15 +40,19 @@ enum ReloadPromptAnswer {
     ReloadAll,
     ReloadSkipCurrent,
     ReloadNone,
+    ReloadNoneAndDiff,
     CloseCurrent
 };
 
 QTCREATOR_UTILS_EXPORT ReloadPromptAnswer reloadPrompt(const FileName &fileName,
                                                        bool modified,
+                                                       bool enableDiffOption,
                                                        QWidget *parent);
 QTCREATOR_UTILS_EXPORT ReloadPromptAnswer reloadPrompt(const QString &title,
                                                        const QString &prompt,
-                                                       const QString &details, QWidget *parent);
+                                                       const QString &details,
+                                                       bool enableDiffOption,
+                                                       QWidget *parent);
 
 enum FileDeletedPromptAnswer {
     FileDeletedClose,
diff --git a/src/plugins/coreplugin/coreplugin.pro b/src/plugins/coreplugin/coreplugin.pro
index 9c8be5cfa76..6de7837acfc 100644
--- a/src/plugins/coreplugin/coreplugin.pro
+++ b/src/plugins/coreplugin/coreplugin.pro
@@ -218,7 +218,8 @@ HEADERS += corejsextensions.h \
     iwelcomepage.h \
     systemsettings.h \
     coreicons.h \
-    editormanager/documentmodel_p.h
+    editormanager/documentmodel_p.h \
+    diffservice.h
 
 FORMS += dialogs/newdialog.ui \
     dialogs/saveitemsdialog.ui \
diff --git a/src/plugins/coreplugin/coreplugin.qbs b/src/plugins/coreplugin/coreplugin.qbs
index ed50f54985d..fe6b3cb75e9 100644
--- a/src/plugins/coreplugin/coreplugin.qbs
+++ b/src/plugins/coreplugin/coreplugin.qbs
@@ -41,6 +41,7 @@ Project {
                 "corejsextensions.cpp", "corejsextensions.h",
                 "coreplugin.cpp", "coreplugin.h",
                 "designmode.cpp", "designmode.h",
+                "diffservice.h",
                 "documentmanager.cpp", "documentmanager.h",
                 "editmode.cpp", "editmode.h",
                 "editortoolbar.cpp", "editortoolbar.h",
diff --git a/src/plugins/coreplugin/dialogs/saveitemsdialog.cpp b/src/plugins/coreplugin/dialogs/saveitemsdialog.cpp
index 885b08e9346..a36ecd9d485 100644
--- a/src/plugins/coreplugin/dialogs/saveitemsdialog.cpp
+++ b/src/plugins/coreplugin/dialogs/saveitemsdialog.cpp
@@ -25,12 +25,15 @@
 
 #include "saveitemsdialog.h"
 
+#include <coreplugin/diffservice.h>
 #include <coreplugin/fileiconprovider.h>
 #include <coreplugin/idocument.h>
 
 #include <utils/fileutils.h>
 #include <utils/hostosinfo.h>
 
+#include <extensionsystem/pluginmanager.h>
+
 #include <QDir>
 #include <QFileInfo>
 #include <QPushButton>
@@ -51,6 +54,12 @@ SaveItemsDialog::SaveItemsDialog(QWidget *parent,
     // QDialogButtonBox's behavior for "destructive" is wrong, the "do not save" should be left-aligned
     const QDialogButtonBox::ButtonRole discardButtonRole = Utils::HostOsInfo::isMacHost()
             ? QDialogButtonBox::ResetRole : QDialogButtonBox::DestructiveRole;
+
+    if (ExtensionSystem::PluginManager::getObject<Core::DiffService>()) {
+        m_diffButton = m_ui.buttonBox->addButton(tr("&Diff"), discardButtonRole);
+        connect(m_diffButton, &QAbstractButton::clicked, this, &SaveItemsDialog::collectFilesToDiff);
+    }
+
     QPushButton *discardButton = m_ui.buttonBox->addButton(tr("Do not Save"), discardButtonRole);
     m_ui.buttonBox->button(QDialogButtonBox::Save)->setDefault(true);
     m_ui.treeWidget->setFocus();
@@ -80,13 +89,13 @@ SaveItemsDialog::SaveItemsDialog(QWidget *parent,
     if (Utils::HostOsInfo::isMacHost())
         m_ui.treeWidget->setAlternatingRowColors(true);
     adjustButtonWidths();
-    updateSaveButton();
+    updateButtons();
 
     connect(m_ui.buttonBox->button(QDialogButtonBox::Save), &QAbstractButton::clicked,
             this, &SaveItemsDialog::collectItemsToSave);
     connect(discardButton, &QAbstractButton::clicked, this, &SaveItemsDialog::discardAll);
     connect(m_ui.treeWidget, &QTreeWidget::itemSelectionChanged,
-            this, &SaveItemsDialog::updateSaveButton);
+            this, &SaveItemsDialog::updateButtons);
 }
 
 void SaveItemsDialog::setMessage(const QString &msg)
@@ -94,19 +103,27 @@ void SaveItemsDialog::setMessage(const QString &msg)
     m_ui.msgLabel->setText(msg);
 }
 
-void SaveItemsDialog::updateSaveButton()
+void SaveItemsDialog::updateButtons()
 {
     int count = m_ui.treeWidget->selectedItems().count();
-    QPushButton *button = m_ui.buttonBox->button(QDialogButtonBox::Save);
+    QPushButton *saveButton = m_ui.buttonBox->button(QDialogButtonBox::Save);
+    bool buttonsEnabled = true;
+    QString saveText = tr("Save");
+    QString diffText = tr("&Diff && Cancel");
     if (count == m_ui.treeWidget->topLevelItemCount()) {
-        button->setEnabled(true);
-        button->setText(tr("Save All"));
+        saveText = tr("Save All");
+        diffText = tr("&Diff All && Cancel");
     } else if (count == 0) {
-        button->setEnabled(false);
-        button->setText(tr("Save"));
+        buttonsEnabled = false;
     } else {
-        button->setEnabled(true);
-        button->setText(tr("Save Selected"));
+        saveText = tr("Save Selected");
+        diffText = tr("&Diff Selected && Cancel");
+    }
+    saveButton->setEnabled(buttonsEnabled);
+    saveButton->setText(saveText);
+    if (m_diffButton) {
+        m_diffButton->setEnabled(buttonsEnabled);
+        m_diffButton->setText(diffText);
     }
 }
 
@@ -145,6 +162,16 @@ void SaveItemsDialog::collectItemsToSave()
     accept();
 }
 
+void SaveItemsDialog::collectFilesToDiff()
+{
+    m_filesToDiff.clear();
+    foreach (QTreeWidgetItem *item, m_ui.treeWidget->selectedItems()) {
+        if (IDocument *doc = item->data(0, Qt::UserRole).value<IDocument*>())
+            m_filesToDiff.append(doc->filePath().toString());
+    }
+    reject();
+}
+
 void SaveItemsDialog::discardAll()
 {
     m_ui.treeWidget->clearSelection();
@@ -156,6 +183,11 @@ QList<IDocument*> SaveItemsDialog::itemsToSave() const
     return m_itemsToSave;
 }
 
+QStringList SaveItemsDialog::filesToDiff() const
+{
+    return m_filesToDiff;
+}
+
 void SaveItemsDialog::setAlwaysSaveMessage(const QString &msg)
 {
     m_ui.saveBeforeBuildCheckBox->setText(msg);
diff --git a/src/plugins/coreplugin/dialogs/saveitemsdialog.h b/src/plugins/coreplugin/dialogs/saveitemsdialog.h
index 623cb2e85f7..1048ca03481 100644
--- a/src/plugins/coreplugin/dialogs/saveitemsdialog.h
+++ b/src/plugins/coreplugin/dialogs/saveitemsdialog.h
@@ -54,15 +54,19 @@ public:
     void setAlwaysSaveMessage(const QString &msg);
     bool alwaysSaveChecked();
     QList<IDocument *> itemsToSave() const;
+    QStringList filesToDiff() const;
 
 private:
     void collectItemsToSave();
+    void collectFilesToDiff();
     void discardAll();
-    void updateSaveButton();
+    void updateButtons();
     void adjustButtonWidths();
 
     Ui::SaveItemsDialog m_ui;
     QList<IDocument*> m_itemsToSave;
+    QStringList m_filesToDiff;
+    QPushButton *m_diffButton = nullptr;
 };
 
 } // namespace Internal
diff --git a/src/plugins/coreplugin/diffservice.h b/src/plugins/coreplugin/diffservice.h
new file mode 100644
index 00000000000..3b282170ddc
--- /dev/null
+++ b/src/plugins/coreplugin/diffservice.h
@@ -0,0 +1,47 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include "core_global.h"
+#include <QObject>
+
+QT_FORWARD_DECLARE_CLASS(QStringList)
+
+namespace Core {
+
+class CORE_EXPORT DiffService
+{
+public:
+    virtual ~DiffService() {}
+
+    virtual void diffModifiedFiles(const QStringList &fileNames) = 0;
+};
+
+} // namespace Core
+
+QT_BEGIN_NAMESPACE
+Q_DECLARE_INTERFACE(Core::DiffService, "Core::DiffService")
+QT_END_NAMESPACE
diff --git a/src/plugins/coreplugin/documentmanager.cpp b/src/plugins/coreplugin/documentmanager.cpp
index 6ba6d61ca24..5a936731fa0 100644
--- a/src/plugins/coreplugin/documentmanager.cpp
+++ b/src/plugins/coreplugin/documentmanager.cpp
@@ -29,6 +29,7 @@
 #include "idocument.h"
 #include "coreconstants.h"
 
+#include <coreplugin/diffservice.h>
 #include <coreplugin/dialogs/readonlyfilesdialog.h>
 #include <coreplugin/dialogs/saveitemsdialog.h>
 #include <coreplugin/editormanager/editormanager.h>
@@ -38,6 +39,8 @@
 #include <coreplugin/editormanager/ieditorfactory.h>
 #include <coreplugin/editormanager/iexternaleditor.h>
 
+#include <extensionsystem/pluginmanager.h>
+
 #include <utils/fileutils.h>
 #include <utils/hostosinfo.h>
 #include <utils/mimetypes/mimedatabase.h>
@@ -606,6 +609,11 @@ static bool saveModifiedFilesHelper(const QList<IDocument *> &documents,
                     (*alwaysSave) = dia.alwaysSaveChecked();
                 if (failedToSave)
                     (*failedToSave) = modifiedDocuments;
+                const QStringList filesToDiff = dia.filesToDiff();
+                if (!filesToDiff.isEmpty()) {
+                    if (auto diffService = ExtensionSystem::PluginManager::getObject<DiffService>())
+                        diffService->diffModifiedFiles(filesToDiff);
+                }
                 return false;
             }
             if (alwaysSave)
@@ -978,6 +986,7 @@ void DocumentManager::checkForReload()
 
     // handle the IDocuments
     QStringList errorStrings;
+    QStringList filesToDiff;
     foreach (IDocument *document, changedIDocuments) {
         IDocument::ChangeTrigger trigger = IDocument::TriggerInternal;
         IDocument::ChangeType type = IDocument::TypePermissions;
@@ -1067,7 +1076,7 @@ void DocumentManager::checkForReload()
             // IDocument wants us to ask
             } else if (type == IDocument::TypeContents) {
                 // content change, IDocument wants to ask user
-                if (previousReloadAnswer == ReloadNone) {
+                if (previousReloadAnswer == ReloadNone || previousReloadAnswer == ReloadNoneAndDiff) {
                     // answer already given, ignore
                     success = document->reload(&errorString, IDocument::FlagIgnore, IDocument::TypeContents);
                 } else if (previousReloadAnswer == ReloadAll) {
@@ -1076,7 +1085,8 @@ void DocumentManager::checkForReload()
                 } else {
                     // Ask about content change
                     previousReloadAnswer = reloadPrompt(document->filePath(), document->isModified(),
-                                                               ICore::dialogParent());
+                                                        ExtensionSystem::PluginManager::getObject<DiffService>(),
+                                                        ICore::dialogParent());
                     switch (previousReloadAnswer) {
                     case ReloadAll:
                     case ReloadCurrent:
@@ -1084,6 +1094,7 @@ void DocumentManager::checkForReload()
                         break;
                     case ReloadSkipCurrent:
                     case ReloadNone:
+                    case ReloadNoneAndDiff:
                         success = document->reload(&errorString, IDocument::FlagIgnore, IDocument::TypeContents);
                         break;
                     case CloseCurrent:
@@ -1091,6 +1102,9 @@ void DocumentManager::checkForReload()
                         break;
                     }
                 }
+                if (previousReloadAnswer == ReloadNoneAndDiff)
+                    filesToDiff.append(document->filePath().toString());
+
             // IDocument wants us to ask, and it's the TypeRemoved case
             } else {
                 // Ask about removed file
@@ -1134,6 +1148,12 @@ void DocumentManager::checkForReload()
 
         d->m_blockedIDocument = 0;
     }
+
+    if (!filesToDiff.isEmpty()) {
+        if (auto diffService = ExtensionSystem::PluginManager::getObject<DiffService>())
+            diffService->diffModifiedFiles(filesToDiff);
+    }
+
     if (!errorStrings.isEmpty())
         QMessageBox::critical(ICore::dialogParent(), tr("File Error"),
                               errorStrings.join(QLatin1Char('\n')));
diff --git a/src/plugins/coreplugin/editormanager/editormanager.cpp b/src/plugins/coreplugin/editormanager/editormanager.cpp
index 7f344ecd95f..4f13bcec2b3 100644
--- a/src/plugins/coreplugin/editormanager/editormanager.cpp
+++ b/src/plugins/coreplugin/editormanager/editormanager.cpp
@@ -39,6 +39,7 @@
 #include <coreplugin/actionmanager/command.h>
 #include <coreplugin/dialogs/openwithdialog.h>
 #include <coreplugin/dialogs/readonlyfilesdialog.h>
+#include <coreplugin/diffservice.h>
 #include <coreplugin/documentmanager.h>
 #include <coreplugin/editormanager/ieditorfactory.h>
 #include <coreplugin/editormanager/iexternaleditor.h>
@@ -2168,11 +2169,21 @@ void EditorManagerPrivate::revertToSaved(IDocument *document)
                            QMessageBox::Yes|QMessageBox::No, ICore::mainWindow());
         msgBox.button(QMessageBox::Yes)->setText(tr("Proceed"));
         msgBox.button(QMessageBox::No)->setText(tr("Cancel"));
+
+        QPushButton *diffButton = nullptr;
+        auto diffService = ExtensionSystem::PluginManager::getObject<DiffService>();
+        if (diffService)
+            diffButton = msgBox.addButton(tr("Cancel && &Diff"), QMessageBox::RejectRole);
+
         msgBox.setDefaultButton(QMessageBox::No);
         msgBox.setEscapeButton(QMessageBox::No);
         if (msgBox.exec() == QMessageBox::No)
             return;
 
+        if (diffService && msgBox.clickedButton() == diffButton) {
+            diffService->diffModifiedFiles(QStringList() << fileName);
+            return;
+        }
     }
     QString errorString;
     if (!document->reload(&errorString, IDocument::FlagReload, IDocument::TypeContents))
diff --git a/src/plugins/diffeditor/diffeditorplugin.cpp b/src/plugins/diffeditor/diffeditorplugin.cpp
index db7936f34af..a04b4b2b862 100644
--- a/src/plugins/diffeditor/diffeditorplugin.cpp
+++ b/src/plugins/diffeditor/diffeditorplugin.cpp
@@ -211,6 +211,66 @@ void DiffAllModifiedFilesController::reload()
 
 /////////////////
 
+class DiffModifiedFilesController : public DiffFilesController
+{
+    Q_OBJECT
+public:
+    DiffModifiedFilesController(Core::IDocument *document, const QStringList &fileNames);
+
+protected:
+    void reload();
+
+private:
+    QStringList m_fileNames;
+};
+
+DiffModifiedFilesController::DiffModifiedFilesController(Core::IDocument *document, const QStringList &fileNames) :
+    DiffFilesController(document), m_fileNames(fileNames)
+{ }
+
+void DiffModifiedFilesController::reload()
+{
+    QList<FileData> fileDataList;
+
+    foreach (const QString fileName, m_fileNames) {
+        TextEditor::TextDocument *textDocument = qobject_cast<TextEditor::TextDocument *>(
+                    Core::DocumentModel::documentForFilePath(fileName));
+
+        if (textDocument && textDocument->isModified()) {
+            QString errorString;
+            Utils::TextFileFormat format = textDocument->format();
+
+            QString leftText;
+            bool leftFileExists = true;
+            const QString fileName = textDocument->filePath().toString();
+            if (Utils::TextFileFormat::readFile(fileName,
+                                                format.codec,
+                                                &leftText, &format, &errorString)
+                    != Utils::TextFileFormat::ReadSuccess) {
+                leftFileExists = false;
+            }
+
+            const QString rightText = textDocument->plainText();
+
+            FileData fileData = diffFiles(leftText, rightText);
+            fileData.leftFileInfo.fileName = fileName;
+            fileData.rightFileInfo.fileName = fileName;
+            fileData.leftFileInfo.typeInfo = tr("Saved");
+            fileData.rightFileInfo.typeInfo = tr("Modified");
+
+            if (!leftFileExists)
+                fileData.fileOperation = FileData::NewFile;
+
+            fileDataList << fileData;
+        }
+    }
+
+    setDiffFiles(fileDataList);
+    reloadFinished(true);
+}
+
+/////////////////
+
 class DiffExternalFilesController : public DiffFilesController
 {
     Q_OBJECT
@@ -273,6 +333,26 @@ void DiffExternalFilesController::reload()
 
 /////////////////
 
+DiffEditorServiceImpl::DiffEditorServiceImpl(QObject *parent) :
+    QObject(parent)
+{
+}
+
+void DiffEditorServiceImpl::diffModifiedFiles(const QStringList &fileNames)
+{
+    const QString documentId = QLatin1String("Diff Modified Files");
+    const QString title = tr("Diff Modified Files");
+    auto const document = qobject_cast<DiffEditorDocument *>(
+                DiffEditorController::findOrCreateDocument(documentId, title));
+    if (!document)
+        return;
+
+    if (!DiffEditorController::controller(document))
+        new DiffModifiedFilesController(document, fileNames);
+    Core::EditorManager::activateEditorForDocument(document);
+    document->reload();
+}
+
 bool DiffEditorPlugin::initialize(const QStringList &arguments, QString *errorMessage)
 {
     Q_UNUSED(arguments)
@@ -309,6 +389,7 @@ bool DiffEditorPlugin::initialize(const QStringList &arguments, QString *errorMe
     updateActions();
 
     addAutoReleasedObject(new DiffEditorFactory(this));
+    addAutoReleasedObject(new DiffEditorServiceImpl(this));
 
     return true;
 }
diff --git a/src/plugins/diffeditor/diffeditorplugin.h b/src/plugins/diffeditor/diffeditorplugin.h
index ba0cab24337..66485660024 100644
--- a/src/plugins/diffeditor/diffeditorplugin.h
+++ b/src/plugins/diffeditor/diffeditorplugin.h
@@ -27,6 +27,7 @@
 
 #include "diffeditor_global.h"
 
+#include <coreplugin/diffservice.h>
 #include <texteditor/textdocument.h>
 #include <extensionsystem/iplugin.h>
 
@@ -37,6 +38,16 @@ namespace Core { class IEditor; }
 namespace DiffEditor {
 namespace Internal {
 
+class DiffEditorServiceImpl : public QObject, public Core::DiffService
+{
+    Q_OBJECT
+    Q_INTERFACES(Core::DiffService)
+public:
+    explicit DiffEditorServiceImpl(QObject *parent = nullptr);
+
+    void diffModifiedFiles(const QStringList &fileNames) override;
+};
+
 class DiffEditorPlugin : public ExtensionSystem::IPlugin
 {
     Q_OBJECT