4 files changed, 7 insertions, 5 deletions
diff --git a/lib/Support/FileUtilities.cpp b/lib/Support/FileUtilities.cpp
index fc8a2f31bd..4d7b2391f0 100644
--- a/lib/Support/FileUtilities.cpp
+++ b/lib/Support/FileUtilities.cpp
@@ -87,9 +87,9 @@ static bool CompareNumbers(const char *&F1P, const char *&F2P,
 
   // If one of the positions is at a space and the other isn't, chomp up 'til
   // the end of the space.
-  while (isspace(*F1P) && F1P != F1End)
+  while (isspace(static_cast<unsigned char>(*F1P)) && F1P != F1End)
     ++F1P;
-  while (isspace(*F2P) && F2P != F2End)
+  while (isspace(static_cast<unsigned char>(*F2P)) && F2P != F2End)
     ++F2P;
 
   // If we stop on numbers, compare their difference.
diff --git a/lib/Support/PathV2.cpp b/lib/Support/PathV2.cpp
index 98d7382b4e..41add96194 100644
--- a/lib/Support/PathV2.cpp
+++ b/lib/Support/PathV2.cpp
@@ -44,7 +44,8 @@ namespace {
 
 #ifdef LLVM_ON_WIN32
     // C:
-    if (path.size() >= 2 && std::isalpha(path[0]) && path[1] == ':')
+    if (path.size() >= 2 && std::isalpha(static_cast<unsigned char>(path[0])) &&
+        path[1] == ':')
       return path.substr(0, 2);
 #endif
 
diff --git a/lib/Support/Windows/Path.inc b/lib/Support/Windows/Path.inc
index 98d8a1850b..f4898e619a 100644
--- a/lib/Support/Windows/Path.inc
+++ b/lib/Support/Windows/Path.inc
@@ -82,7 +82,7 @@ Path::isValid() const {
   pos = path.rfind(':',len);
   size_t rootslash = 0;
   if (pos != std::string::npos) {
-    if (pos != 1 || !isalpha(path[0]) || len < 3)
+    if (pos != 1 || !isalpha(static_cast<unsigned char>(path[0])) || len < 3)
       return false;
       rootslash = 2;
   }
diff --git a/lib/Support/raw_ostream.cpp b/lib/Support/raw_ostream.cpp
index 106864dd05..f71abd3b24 100644
--- a/lib/Support/raw_ostream.cpp
+++ b/lib/Support/raw_ostream.cpp
@@ -241,7 +241,8 @@ raw_ostream &raw_ostream::operator<<(double N) {
       if (cs == '+' || cs == '-') {
         int c1 = buf[len - 2];
         int c0 = buf[len - 1];
-        if (isdigit(c1) && isdigit(c0)) {
+        if (isdigit(static_cast<unsigned char>(c1)) &&
+            isdigit(static_cast<unsigned char>(c0))) {
           // Trim leading '0': "...e+012" -> "...e+12\0"
           buf[len - 3] = c1;
           buf[len - 2] = c0;