Index: clang/lib/AST/FormatString.cpp
===================================================================
--- clang/lib/AST/FormatString.cpp
+++ clang/lib/AST/FormatString.cpp
@@ -401,8 +401,21 @@
           case BuiltinType::UInt:
             return T == C.IntTy ? Match : NoMatch;
           case BuiltinType::Long:
+            // Win32 platform mixes long and int for size_t-like purposes.
+            // ssize_t is int, but platform type SSIZE_T is long.
+            if ((isSizeT() || isPtrdiffT()) &&
+                C.getTargetInfo().getTriple().isOSMSVCRT() &&
+                C.getTargetInfo().getTriple().isArch32Bit())
+              return Match;
             return T == C.UnsignedLongTy ? Match : NoMatch;
           case BuiltinType::ULong:
+            // Win32 platform mixes long and int for size_t-like purposes.
+            // size_t is unsigned int, but platform type SIZE_T is unsigned
+            // long.
+            if ((isSizeT() || isPtrdiffT()) &&
+                C.getTargetInfo().getTriple().isOSMSVCRT() &&
+                C.getTargetInfo().getTriple().isArch32Bit())
+              return Match;
             return T == C.LongTy ? Match : NoMatch;
           case BuiltinType::LongLong:
             return T == C.UnsignedLongLongTy ? Match : NoMatch;
Index: clang/lib/AST/PrintfFormatString.cpp
===================================================================
--- clang/lib/AST/PrintfFormatString.cpp
+++ clang/lib/AST/PrintfFormatString.cpp
@@ -527,8 +527,8 @@
         return ArgType::makeSizeT(ArgType(Ctx.getSignedSizeType(), "ssize_t"));
       case LengthModifier::AsInt3264:
         return Ctx.getTargetInfo().getTriple().isArch64Bit()
-                   ? ArgType(Ctx.LongLongTy, "__int64")
-                   : ArgType(Ctx.IntTy, "__int32");
+                   ? ArgType::makeSizeT(ArgType(Ctx.LongLongTy, "__int64"))
+                   : ArgType::makeSizeT(ArgType(Ctx.IntTy, "__int32"));
       case LengthModifier::AsPtrDiff:
         return ArgType::makePtrdiffT(
             ArgType(Ctx.getPointerDiffType(), "ptrdiff_t"));
@@ -562,8 +562,10 @@
         return ArgType::makeSizeT(ArgType(Ctx.getSizeType(), "size_t"));
       case LengthModifier::AsInt3264:
         return Ctx.getTargetInfo().getTriple().isArch64Bit()
-                   ? ArgType(Ctx.UnsignedLongLongTy, "unsigned __int64")
-                   : ArgType(Ctx.UnsignedIntTy, "unsigned __int32");
+                   ? ArgType::makeSizeT(
+                         ArgType(Ctx.UnsignedLongLongTy, "unsigned __int64"))
+                   : ArgType::makeSizeT(
+                         ArgType(Ctx.UnsignedIntTy, "unsigned __int32"));
       case LengthModifier::AsPtrDiff:
         return ArgType::makePtrdiffT(
             ArgType(Ctx.getUnsignedPointerDiffType(), "unsigned ptrdiff_t"));
Index: clang/test/Sema/format-strings-ms.c
===================================================================
--- clang/test/Sema/format-strings-ms.c
+++ clang/test/Sema/format-strings-ms.c
@@ -21,17 +21,35 @@
 void signed_test() {
   short val = 30;
   printf("val = %I64d\n", val); // expected-warning{{format specifies type '__int64' (aka 'long long') but the argument has type 'short'}}
+  printf("val = %Id\n", val);
   long long bigval = 30;
   printf("val = %I32d\n", bigval); // expected-warning{{format specifies type '__int32' (aka 'int') but the argument has type 'long long'}}
   printf("val = %Id\n", bigval); // expected-warning{{format specifies type '__int32' (aka 'int') but the argument has type 'long long'}}
+  int ival = 30;
+  printf("%Id", ival);
+  printf("%zd", ival);
+  printf("%td", ival);
+  long lval = 30;
+  printf("%Id", lval);
+  printf("%zd", lval);
+  printf("%td", lval);
 }
 
 void unsigned_test() {
   unsigned short val = 30;
   printf("val = %I64u\n", val); // expected-warning{{format specifies type 'unsigned __int64' (aka 'unsigned long long') but the argument has type 'unsigned short'}}
+  printf("val = %Iu\n", val);
   unsigned long long bigval = 30;
   printf("val = %I32u\n", bigval); // expected-warning{{format specifies type 'unsigned __int32' (aka 'unsigned int') but the argument has type 'unsigned long long'}}
   printf("val = %Iu\n", bigval); // expected-warning{{format specifies type 'unsigned __int32' (aka 'unsigned int') but the argument has type 'unsigned long long'}}
+  unsigned int ival = 30;
+  printf("%Iu", ival);
+  printf("%zu", ival);
+  printf("%tu", ival);
+  unsigned long lval = 30;
+  printf("%Iu", lval);
+  printf("%zu", lval);
+  printf("%tu", lval);
 }
 
 void w_test(wchar_t c, wchar_t *s) {