diff --git a/clang/test/Preprocessor/Inputs/llvm-windres.h b/clang/test/Preprocessor/Inputs/llvm-windres.h
index 411ec48a8af9f..ef6bc47885a1a 100644
--- a/clang/test/Preprocessor/Inputs/llvm-windres.h
+++ b/clang/test/Preprocessor/Inputs/llvm-windres.h
@@ -1,10 +1,12 @@
 #ifndef RC_INVOKED
-#error RC_INVOKED not defined
+#  error RC_INVOKED not defined
 #endif
-#ifndef _WIN32
-#error _WIN32 not defined
-#endif
-#ifndef __MINGW32__
-#error __MINGW32__ not defined
+#ifndef __CYGWIN__
+#  ifndef _WIN32
+#    error _WIN32 not defined
+#  endif
+#  ifndef __MINGW32__
+#    error __MINGW32__ not defined
+#  endif
 #endif
 #define MY_ID 42
diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index d4a34555ed820..060ec9d9cf0f7 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -2062,7 +2062,7 @@ void TargetLoweringBase::insertSSPDeclarations(Module &M) const {
 
     // FreeBSD has "__stack_chk_guard" defined externally on libc.so
     if (M.getDirectAccessExternalData() &&
-        !TM.getTargetTriple().isWindowsGNUEnvironment() &&
+        !TM.getTargetTriple().isOSCygMing() &&
         !(TM.getTargetTriple().isPPC64() &&
           TM.getTargetTriple().isOSFreeBSD()) &&
         (!TM.getTargetTriple().isOSDarwin() ||
diff --git a/llvm/test/CodeGen/X86/stack-protector.ll b/llvm/test/CodeGen/X86/stack-protector.ll
index f4f3ae4f55f2e..772e7761fae80 100644
--- a/llvm/test/CodeGen/X86/stack-protector.ll
+++ b/llvm/test/CodeGen/X86/stack-protector.ll
@@ -6,6 +6,7 @@
 ; RUN: llc -mtriple=amd64-pc-openbsd < %s -o - | FileCheck --check-prefix=OPENBSD-AMD64 %s
 ; RUN: llc -mtriple=i386-pc-windows-msvc < %s -o - | FileCheck -check-prefix=MSVC-I386 %s
 ; RUN: llc -mtriple=x86_64-w64-mingw32 < %s -o - | FileCheck --check-prefix=MINGW-X64 %s
+; RUN: llc -mtriple=x86_64-pc-cygwin < %s -o - | FileCheck --check-prefix=MINGW-X64 %s
 ; RUN: llc -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck --check-prefix=IGNORE_INTRIN %s
 
 %struct.foo = type { [16 x i8] }
diff --git a/llvm/test/CodeGen/X86/win32-ssp.ll b/llvm/test/CodeGen/X86/win32-ssp.ll
index 536a6d50be56a..259f0391cfe9b 100644
--- a/llvm/test/CodeGen/X86/win32-ssp.ll
+++ b/llvm/test/CodeGen/X86/win32-ssp.ll
@@ -1,7 +1,9 @@
 ; RUN: llc -mtriple=x86_64-w64-mingw32        < %s -o - | FileCheck --check-prefix=MINGW %s
+; RUN: llc -mtriple=x86_64-pc-cygwin          < %s -o - | FileCheck --check-prefix=MINGW %s
 ; RUN: llc -mtriple=x86_64-pc-windows-itanium < %s -o - | FileCheck --check-prefix=MSVC  %s
 ; RUN: llc -mtriple=x86_64-pc-windows-msvc    < %s -o - | FileCheck --check-prefix=MSVC  %s
 ; RUN: llc -mtriple=i686-w64-mingw32          < %s -o - | FileCheck --check-prefix=MINGW %s
+; RUN: llc -mtriple=i686-pc-cygwin            < %s -o - | FileCheck --check-prefix=MINGW %s
 
 declare void @llvm.lifetime.start.p0(i64, ptr nocapture)
 declare dso_local void @other(ptr)
diff --git a/llvm/test/tools/llvm-rc/windres-preproc.test b/llvm/test/tools/llvm-rc/windres-preproc.test
index 423ad0252f0ab..43ed0a61c39d8 100644
--- a/llvm/test/tools/llvm-rc/windres-preproc.test
+++ b/llvm/test/tools/llvm-rc/windres-preproc.test
@@ -4,7 +4,7 @@
 
 ; RUN: llvm-windres -### --include-dir %p/incdir1 --include %p/incdir2 "-DFOO1=\\\"foo bar\\\"" -UFOO2 -D FOO3 --preprocessor-arg "-DFOO4=\\\"baz baz\\\"" -DFOO5=\"bar\" %p/Inputs/empty.rc %t.res | FileCheck %s --check-prefix=CHECK1
 ; RUN: llvm-windres -### --include-dir %p/incdir1 --include %p/incdir2 "-DFOO1=\"foo bar\"" -UFOO2 -D FOO3 --preprocessor-arg "-DFOO4=\"baz baz\"" "-DFOO5=bar" %p/Inputs/empty.rc %t.res --use-temp-file | FileCheck %s --check-prefix=CHECK1
-; CHECK1: {{^}} "clang" "--driver-mode=gcc" "-target" "{{.*}}-{{.*}}{{mingw32|windows-gnu}}" "-E" "-xc" "-DRC_INVOKED" "-I" "{{.*}}incdir1" "-I" "{{.*}}incdir2" "-D" "FOO1=\"foo bar\"" "-U" "FOO2" "-D" "FOO3" "-DFOO4=\"baz baz\"" "-D" "FOO5=bar" "{{.*}}empty.rc" "-o" "{{.*}}preproc-{{.*}}.rc"{{$}}
+; CHECK1: {{^}} "clang" "--driver-mode=gcc" "-target" "{{.*}}-{{.*}}{{mingw32|cygwin|windows-gnu|windows-cygnus}}" "-E" "-xc" "-DRC_INVOKED" "-I" "{{.*}}incdir1" "-I" "{{.*}}incdir2" "-D" "FOO1=\"foo bar\"" "-U" "FOO2" "-D" "FOO3" "-DFOO4=\"baz baz\"" "-D" "FOO5=bar" "{{.*}}empty.rc" "-o" "{{.*}}preproc-{{.*}}.rc"{{$}}
 ; RUN: llvm-windres -### --preprocessor "i686-w64-mingw32-gcc" --preprocessor-arg -E "-DFOO=\\\"foo bar\\\"" %p/Inputs/empty.rc %t.res | FileCheck %s --check-prefix=CHECK2
 ; CHECK2: {{^}} "{{.*}}i686-w64-mingw32-gcc" "-E" "-D" "FOO=\"foo bar\"" "{{.*}}empty.rc" "-o" "{{.*}}preproc-{{.*}}.rc"{{$}}
 
@@ -13,7 +13,7 @@
 ; RUN: rm -rf %t-bin/testbin
 ; RUN: mkdir -p %t-bin/testbin
 ; RUN: ln -s llvm-windres %t-bin/testbin/i686-w64-mingw32-gcc
-; RUN: env PATH=%t-bin/testbin llvm-windres -### --preprocessor i686-w64-mingw32-gcc --preprocessor-arg -E --preprocessor-arg -xc -DRC_INVOKED %p/Inputs/empty.rc %t.res | FileCheck %s --check-prefix=CHECK3
+; RUN: env PATH="%t-bin/testbin:$PATH" llvm-windres -### --preprocessor i686-w64-mingw32-gcc --preprocessor-arg -E --preprocessor-arg -xc -DRC_INVOKED %p/Inputs/empty.rc %t.res | FileCheck %s --check-prefix=CHECK3
 ; CHECK3: {{^}} "{{.*}}/testbin/i686-w64-mingw32-gcc" "-E" "-xc" "-D" "RC_INVOKED" "{{.*}}empty.rc" "-o" "{{.*}}preproc-{{.*}}.rc"{{$}}
 
 
diff --git a/llvm/tools/llvm-rc/llvm-rc.cpp b/llvm/tools/llvm-rc/llvm-rc.cpp
index 73621543848a1..f623342366515 100644
--- a/llvm/tools/llvm-rc/llvm-rc.cpp
+++ b/llvm/tools/llvm-rc/llvm-rc.cpp
@@ -201,7 +201,7 @@ std::string getMingwTriple() {
   Triple T(sys::getDefaultTargetTriple());
   if (!isUsableArch(T.getArch()))
     T.setArch(getDefaultFallbackArch());
-  if (T.isWindowsGNUEnvironment())
+  if (T.isOSCygMing())
     return T.str();
   // Write out the literal form of the vendor/env here, instead of
   // constructing them with enum values (which end up with them in