diff --git a/clang/lib/Lex/Lexer.cpp b/clang/lib/Lex/Lexer.cpp
--- a/clang/lib/Lex/Lexer.cpp
+++ b/clang/lib/Lex/Lexer.cpp
@@ -2446,44 +2446,69 @@
   // Back up off the newline.
   --CurPtr;
 
-  // If this is a two-character newline sequence, skip the other character.
-  if (CurPtr[0] == '\n' || CurPtr[0] == '\r') {
-    // \n\n or \r\r -> not escaped newline.
-    if (CurPtr[0] == CurPtr[1])
-      return false;
-    // \n\r or \r\n -> skip the newline.
-    --CurPtr;
-  }
-
-  // If we have horizontal whitespace, skip over it.  We allow whitespace
-  // between the slash and newline.
   bool HasSpace = false;
-  while (isHorizontalWhitespace(*CurPtr) || *CurPtr == 0) {
-    --CurPtr;
-    HasSpace = true;
-  }
+  while (true) {
+    // If this is a two-character newline sequence, skip the other character.
+    if (CurPtr[0] == '\n' || CurPtr[0] == '\r') {
+      // \n\n or \r\r -> not escaped newline.
+      if (CurPtr[0] == CurPtr[1])
+        return false;
+      // \n\r or \r\n -> skip the newline.
+      --CurPtr;
+    }
+
+    // If we have horizontal whitespace, skip over it.  We allow whitespace
+    // between the slash and newline.
+    while (isHorizontalWhitespace(*CurPtr) || *CurPtr == 0) {
+      --CurPtr;
+      HasSpace = true;
+    }
+
+    // If we have a slash, we know this is an escaped newline.
+    if (*CurPtr == '\\') {
+      // Found the *, we're done
+      if (CurPtr[-1] == '*') break;
+
+      // Found another possible escaped newline
+      if (CurPtr[-1] == '\n' || CurPtr[-1] == '\r') {
+        --CurPtr;
+        continue;
+      }
 
-  // If we have a slash, we know this is an escaped newline.
-  if (*CurPtr == '\\') {
-    if (CurPtr[-1] != '*') return false;
-  } else {
-    // It isn't a slash, is it the ?? / trigraph?
-    if (CurPtr[0] != '/' || CurPtr[-1] != '?' || CurPtr[-2] != '?' ||
-        CurPtr[-3] != '*')
       return false;
+    } else {
+      // It isn't a slash, is it the ?? / trigraph?
+      if (CurPtr[0] != '/' || CurPtr[-1] != '?' || CurPtr[-2] != '?')
+        return false;
+
+      // This is the trigraph ending the comment.  Emit a stern warning!
+      CurPtr -= 2;
+
+      if (CurPtr[-1] == '*') {
+        // If no trigraphs are enabled, warn that we ignored this trigraph and
+        // ignore this * character.
+        if (!L->getLangOpts().Trigraphs) {
+          if (!L->isLexingRawMode())
+            L->Diag(CurPtr, diag::trigraph_ignored_block_comment);
+          return false;
+        }
+        if (!L->isLexingRawMode())
+          L->Diag(CurPtr, diag::trigraph_ends_block_comment);
 
-    // This is the trigraph ending the comment.  Emit a stern warning!
-    CurPtr -= 2;
+        break;
+      } else if (CurPtr[-1] == '\n' || CurPtr[-1] == '\r') {
+        // If no trigraphs are enabled, warn that we ignored this trigraph
+        if (!L->getLangOpts().Trigraphs) {
+          if (!L->isLexingRawMode())
+            L->Diag(CurPtr, diag::trigraph_ignored);
+          return false;
+        }
+        --CurPtr;
+        continue;
+      }
 
-    // If no trigraphs are enabled, warn that we ignored this trigraph and
-    // ignore this * character.
-    if (!L->getLangOpts().Trigraphs) {
-      if (!L->isLexingRawMode())
-        L->Diag(CurPtr, diag::trigraph_ignored_block_comment);
       return false;
     }
-    if (!L->isLexingRawMode())
-      L->Diag(CurPtr, diag::trigraph_ends_block_comment);
   }
 
   // Warn about having an escaped newline between the */ characters.