Index: lib/CodeGen/TargetInfo.cpp
===================================================================
--- lib/CodeGen/TargetInfo.cpp
+++ lib/CodeGen/TargetInfo.cpp
@@ -2715,9 +2715,6 @@
     return ABIArgInfo::getDirect(llvm::IntegerType::get(getVMContext(), Size));
   }
 
-  if (Ty->isPromotableIntegerType())
-    return ABIArgInfo::getExtend();
-
   return ABIArgInfo::getDirect();
 }
 
Index: test/CodeGen/2007-06-18-SextAttrAggregate.c
===================================================================
--- test/CodeGen/2007-06-18-SextAttrAggregate.c
+++ test/CodeGen/2007-06-18-SextAttrAggregate.c
@@ -1,11 +1,13 @@
 // RUN: %clang_cc1 %s -o - -emit-llvm | FileCheck %s
-// XFAIL: aarch64, arm64
+// XFAIL: aarch64, arm64, x86_64-pc-win32
 
 // PR1513
 
 // AArch64 ABI actually requires the reverse of what this is testing: the callee
 // does any extensions and remaining bits are unspecified.
 
+// Win64 ABI does expect extensions for type smaller than 64bits.
+
 // Technically this test wasn't written to test that feature, but it's a
 // valuable check nevertheless.
 
Index: test/CodeGen/x86_64-arguments-win32.c
===================================================================
--- /dev/null
+++ test/CodeGen/x86_64-arguments-win32.c
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -w -triple x86_64-pc-win32 -emit-llvm -o - %s | FileCheck %s
+
+// To be ABI compatible with code generated by MSVC, there shouldn't be any
+// sign/zero extensions on types smaller than 64bit.
+
+// CHECK-LABEL: define void @f1(i8 %a)
+void f1(char a) {}
+
+// CHECK-LABEL: define void @f2(i8 %a)
+void f2(unsigned char a) {}
+
+// CHECK-LABEL: define void @f3(i16 %a)
+void f3(short a) {}
+
+// CHECK-LABEL: define void @f4(i16 %a)
+void f4(unsigned short a) {}