diff --git a/lib/CodeGen/CoverageMappingGen.cpp b/lib/CodeGen/CoverageMappingGen.cpp
index 1bfa7cd..0570cd0 100644
--- a/lib/CodeGen/CoverageMappingGen.cpp
+++ b/lib/CodeGen/CoverageMappingGen.cpp
@@ -34,11 +34,12 @@ namespace {
 /// \brief A region of source code that can be mapped to a counter.
 struct SourceMappingRegion {
   enum RegionFlags {
-    /// \brief This region won't be emitted if it wasn't extended.
+    /// \brief This region won't be emitted if the "file" that contains this
+    /// region consists only of this region.
     /// This is useful so that we won't emit source ranges for single tokens
     /// that we don't really care that much about, like:
     ///   the '(' token in #define MACRO (
-    IgnoreIfNotExtended = 0x0001,
+    IgnoreIfFileOnlyHasThisRegion = 0x0001,
   };
 
   FileID File, MacroArgumentFile;
@@ -99,8 +100,8 @@ struct SourceMappingRegion {
   void mergeByExtendingTo(SourceMappingRegion &R) {
     LocEnd = R.LocEnd;
     AlternativeLocEnd = R.LocStart;
-    if (hasFlag(IgnoreIfNotExtended))
-      clearFlag(IgnoreIfNotExtended);
+    if (hasFlag(IgnoreIfFileOnlyHasThisRegion))
+      clearFlag(IgnoreIfFileOnlyHasThisRegion);
   }
 };
 
@@ -381,14 +382,31 @@ public:
   /// \brief Generate the coverage counter mapping regions from collected
   /// source regions.
   void emitSourceRegions() {
+    struct FileRegionInfo {
+      bool HasMultipleRegions;
+
+      FileRegionInfo() : HasMultipleRegions(false) {}
+    };
+
+    llvm::SmallDenseMap<FileID, FileRegionInfo, 8> FileRegionInfoMapping;
+
+    for (const auto &R : SourceRegions) {
+      auto It = FileRegionInfoMapping.find(R.File);
+      if (It == FileRegionInfoMapping.end()) {
+        FileRegionInfoMapping.insert(std::make_pair(R.File, FileRegionInfo()));
+        continue;
+      }
+      It->second.HasMultipleRegions = true;
+    }
+
     for (const auto &R : SourceRegions) {
       SourceLocation LocStart = R.LocStart;
       SourceLocation LocEnd = R.LocEnd;
       if (SM.getFileID(LocEnd) != R.File)
         LocEnd = R.AlternativeLocEnd;
 
-      if (R.hasFlag(SourceMappingRegion::IgnoreIfNotExtended) &&
-          LocStart == LocEnd)
+      if (R.hasFlag(SourceMappingRegion::IgnoreIfFileOnlyHasThisRegion) &&
+          !FileRegionInfoMapping[R.File].HasMultipleRegions)
         continue;
 
       LocEnd = getPreciseTokenLocEnd(LocEnd);
@@ -627,12 +645,13 @@ struct CounterCoverageMappingBuilder
   void mapToken(SourceLocation LocStart) {
     CoverageMappingBuilder::mapSourceCodeRange(
         LocStart, LocStart, CurrentRegionCount,
-        SourceMappingRegion::IgnoreIfNotExtended);
+        SourceMappingRegion::IgnoreIfFileOnlyHasThisRegion);
   }
 
   void mapToken(const SourceMappingState &State, SourceLocation LocStart) {
     CoverageMappingBuilder::mapSourceCodeRange(
-        State, LocStart, LocStart, SourceMappingRegion::IgnoreIfNotExtended);
+        State, LocStart, LocStart,
+        SourceMappingRegion::IgnoreIfFileOnlyHasThisRegion);
   }
 
   void VisitStmt(const Stmt *S) {
@@ -1021,6 +1040,10 @@ struct CounterCoverageMappingBuilder
     Visit(E->getSubExpr());
   }
 
+  void VisitImplicitCastExpr(const ImplicitCastExpr *E) {
+    Visit(E->getSubExpr());
+  }
+
   // Map literals as tokens so that the macros like #define PI 3.14
   // won't generate coverage mapping regions.
 
diff --git a/test/CoverageMapping/casts.c b/test/CoverageMapping/casts.c
index 94c13dc..ef08c19 100644
--- a/test/CoverageMapping/casts.c
+++ b/test/CoverageMapping/casts.c
@@ -6,6 +6,13 @@ int main() {                                                   // CHECK: File 0,
   return 0;
 }
 
+#define N 32
 
+              // CHECK: foo
+void foo() {  // CHECK-NEXT: File 0, [[@LINE]]:12 -> [[@LINE+4]]:2 = #0 (HasCodeBefore = 0)
+  char c = N;
+  if (0) {    // CHECK-NEXT: File 0, [[@LINE]]:10 -> [[@LINE+1]]:4 = #1 (HasCodeBefore = 0)
+  }
+}
 
 
diff --git a/test/CoverageMapping/exprregions.c b/test/CoverageMapping/exprregions.c
new file mode 100644
index 0000000..c62cc07
--- /dev/null
+++ b/test/CoverageMapping/exprregions.c
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -fprofile-instr-generate -fcoverage-mapping -dump-coverage-mapping -emit-llvm-only -main-file-name exprregions.c %s | FileCheck %s
+
+int main() {    // CHECK: File 0, [[@LINE]]:12 -> [[@LINE+5]]:2 = #0 (HasCodeBefore = 0)
+  int x =   0 ?
+            1 : // CHECK-NEXT: File 0, [[@LINE]]:13 -> [[@LINE]]:14 = #1 (HasCodeBefore = 0)
+            0;  // CHECK-NEXT: File 0, [[@LINE]]:13 -> [[@LINE]]:14 = (#0 - #1) (HasCodeBefore = 0)
+  return 0;
+}