Index: lib/Format/UnwrappedLineFormatter.cpp
===================================================================
--- lib/Format/UnwrappedLineFormatter.cpp
+++ lib/Format/UnwrappedLineFormatter.cpp
@@ -304,9 +304,15 @@
     if (TheLine->First->is(tok::l_brace) && TheLine->First == TheLine->Last &&
         I != AnnotatedLines.begin() &&
         I[-1]->First->isOneOf(tok::kw_if, tok::kw_while, tok::kw_for)) {
-      return Style.AllowShortBlocksOnASingleLine
-                 ? tryMergeSimpleBlock(I - 1, E, Limit)
-                 : 0;
+      unsigned MergedLines = 0;
+      if (Style.AllowShortBlocksOnASingleLine) {
+        MergedLines = tryMergeSimpleBlock(I - 1, E, Limit);
+        // If we managed to merge the block, discard the first  merged line
+        // since we are merging starting from I.
+        if (MergedLines > 0)
+          --MergedLines;
+      }
+      return MergedLines;
     }
     // Try to merge a block with left brace wrapped that wasn't yet covered
     if (TheLine->Last->is(tok::l_brace)) {
Index: unittests/Format/FormatTest.cpp
===================================================================
--- unittests/Format/FormatTest.cpp
+++ unittests/Format/FormatTest.cpp
@@ -588,6 +588,23 @@
                AllowSimpleBracedStatements);
 }
 
+TEST_F(FormatTest, ShortBlocksInMacrosDontMergeWithCodeAfterMacro) {
+  FormatStyle Style = getLLVMStyleWithColumns(60);
+  Style.AllowShortBlocksOnASingleLine = true;
+  Style.AllowShortIfStatementsOnASingleLine = true;
+  Style.BreakBeforeBraces = FormatStyle::BS_Allman;
+  EXPECT_EQ("#define A                                                  \\\n"
+            "  if (HANDLEwernufrnuLwrmviferuvnierv)                     \\\n"
+            "  { RET_ERR1_ANUIREUINERUIFNIOAerwfwrvnuier; }\n"
+            "X;",
+            format("#define A \\\n"
+                   "   if (HANDLEwernufrnuLwrmviferuvnierv) { \\\n"
+                   "      RET_ERR1_ANUIREUINERUIFNIOAerwfwrvnuier; \\\n"
+                   "   }\n"
+                   "X;",
+                   Style));
+}
+
 TEST_F(FormatTest, ParseIfElse) {
   verifyFormat("if (true)\n"
                "  if (true)\n"