Index: runtime/cmake/LibompHandleFlags.cmake
===================================================================
--- runtime/cmake/LibompHandleFlags.cmake
+++ runtime/cmake/LibompHandleFlags.cmake
@@ -50,6 +50,7 @@
   libomp_append(flags_local /GS LIBOMP_HAVE_GS_FLAG)
   libomp_append(flags_local /EHsc LIBOMP_HAVE_EHSC_FLAG)
   libomp_append(flags_local /Oy- LIBOMP_HAVE_OY__FLAG)
+  libomp_append(flags_local -mrtm LIBOMP_HAVE_MRTM_FLAG)
   # Intel(R) C Compiler flags
   libomp_append(flags_local /Qsafeseh LIBOMP_HAVE_QSAFESEH_FLAG)
   libomp_append(flags_local -Qoption,cpp,--extended_float_types LIBOMP_HAVE_EXTENDED_FLOAT_TYPES_FLAG)
Index: runtime/cmake/config-ix.cmake
===================================================================
--- runtime/cmake/config-ix.cmake
+++ runtime/cmake/config-ix.cmake
@@ -73,13 +73,18 @@
 libomp_check_architecture_flag(-mmic LIBOMP_HAVE_MMIC_FLAG)
 libomp_check_architecture_flag(-m32 LIBOMP_HAVE_M32_FLAG)
 if(WIN32)
-  # Check Windows MSVC style flags.
-  check_c_compiler_flag(/TP LIBOMP_HAVE_TP_FLAG)
-  check_cxx_compiler_flag(/EHsc LIBOMP_HAVE_EHSC_FLAG)
-  check_cxx_compiler_flag(/GS LIBOMP_HAVE_GS_FLAG)
-  check_cxx_compiler_flag(/Oy- LIBOMP_HAVE_Oy__FLAG)
-  check_cxx_compiler_flag(/arch:SSE2 LIBOMP_HAVE_ARCH_SSE2_FLAG)
-  check_cxx_compiler_flag(/Qsafeseh LIBOMP_HAVE_QSAFESEH_FLAG)
+  if(MSVC)
+    # Check Windows MSVC style flags.
+    check_c_compiler_flag(/TP LIBOMP_HAVE_TP_FLAG)
+    check_cxx_compiler_flag(/EHsc LIBOMP_HAVE_EHSC_FLAG)
+    check_cxx_compiler_flag(/GS LIBOMP_HAVE_GS_FLAG)
+    check_cxx_compiler_flag(/Oy- LIBOMP_HAVE_Oy__FLAG)
+    check_cxx_compiler_flag(/arch:SSE2 LIBOMP_HAVE_ARCH_SSE2_FLAG)
+    check_cxx_compiler_flag(/Qsafeseh LIBOMP_HAVE_QSAFESEH_FLAG)
+  endif()
+  if(CMAKE_C_COMPILER_ID STREQUAL "Clang")
+    check_c_compiler_flag(-mrtm LIBOMP_HAVE_MRTM_FLAG)
+  endif()
   # It is difficult to create a dummy masm assembly file
   # and then check the MASM assembler to see if these flags exist and work,
   # so we assume they do for Windows.
Index: runtime/src/kmp.h
===================================================================
--- runtime/src/kmp.h
+++ runtime/src/kmp.h
@@ -544,11 +544,15 @@
 
 #if KMP_OS_WINDOWS
 #define USE_CBLKDATA
+#if !defined(__MINGW32__)
 #pragma warning(push)
 #pragma warning(disable : 271 310)
+#endif
 #include <windows.h>
+#if !defined(__MINGW32__)
 #pragma warning(pop)
 #endif
+#endif
 
 #if KMP_OS_UNIX
 #include <dlfcn.h>
@@ -560,7 +564,7 @@
 
 // GROUP_AFFINITY is already defined for _MSC_VER>=1600 (VS2010 and later).
 #if KMP_OS_WINDOWS
-#if _MSC_VER < 1600
+#if _MSC_VER < 1600 && !defined(__MINGW32__)
 typedef struct GROUP_AFFINITY {
   KAFFINITY Mask;
   WORD Group;
Index: runtime/src/kmp_affinity.h
===================================================================
--- runtime/src/kmp_affinity.h
+++ runtime/src/kmp_affinity.h
@@ -375,26 +375,26 @@
       mask[i / BITS_PER_MASK_T] &= ~((mask_t)1 << (i % BITS_PER_MASK_T));
     }
     void zero() override {
-      for (size_t i = 0; i < __kmp_num_proc_groups; ++i)
+      for (size_t i = 0; i < static_cast<size_t>(__kmp_num_proc_groups); ++i)
         mask[i] = 0;
     }
     void copy(const KMPAffinity::Mask *src) override {
       const Mask *convert = static_cast<const Mask *>(src);
-      for (size_t i = 0; i < __kmp_num_proc_groups; ++i)
+      for (size_t i = 0; i < static_cast<size_t>(__kmp_num_proc_groups); ++i)
         mask[i] = convert->mask[i];
     }
     void bitwise_and(const KMPAffinity::Mask *rhs) override {
       const Mask *convert = static_cast<const Mask *>(rhs);
-      for (size_t i = 0; i < __kmp_num_proc_groups; ++i)
+      for (size_t i = 0; i < static_cast<size_t>(__kmp_num_proc_groups); ++i)
         mask[i] &= convert->mask[i];
     }
     void bitwise_or(const KMPAffinity::Mask *rhs) override {
       const Mask *convert = static_cast<const Mask *>(rhs);
-      for (size_t i = 0; i < __kmp_num_proc_groups; ++i)
+      for (size_t i = 0; i < static_cast<size_t>(__kmp_num_proc_groups); ++i)
         mask[i] |= convert->mask[i];
     }
     void bitwise_not() override {
-      for (size_t i = 0; i < __kmp_num_proc_groups; ++i)
+      for (size_t i = 0; i < static_cast<size_t>(__kmp_num_proc_groups); ++i)
         mask[i] = ~(mask[i]);
     }
     int begin() const override {
Index: runtime/src/kmp_dispatch.cpp
===================================================================
--- runtime/src/kmp_dispatch.cpp
+++ runtime/src/kmp_dispatch.cpp
@@ -24,7 +24,7 @@
 #include "kmp_itt.h"
 #include "kmp_stats.h"
 #include "kmp_str.h"
-#if KMP_OS_WINDOWS && KMP_ARCH_X86
+#if KMP_OS_WINDOWS && KMP_ARCH_X86 && !KMP_COMPILER_CLANG
 #include <float.h>
 #endif
 #include "kmp_lock.h"
@@ -478,7 +478,7 @@
         /* commonly used term: (2 nproc - 1)/(2 nproc) */
         DBL x;
 
-#if KMP_OS_WINDOWS && KMP_ARCH_X86
+#if KMP_OS_WINDOWS && KMP_ARCH_X86 && !KMP_COMPILER_CLANG
         /* Linux* OS already has 64-bit computation by default for long double,
            and on Windows* OS on Intel(R) 64, /Qlong_double doesn't work. On
            Windows* OS on IA-32 architecture, we need to set precision to 64-bit
@@ -573,7 +573,7 @@
         pr->u.p.count = tc - __kmp_dispatch_guided_remaining(
                                  tc, GUIDED_ANALYTICAL_WORKAROUND, cross) -
                         cross * chunk;
-#if KMP_OS_WINDOWS && KMP_ARCH_X86
+#if KMP_OS_WINDOWS && KMP_ARCH_X86 && !KMP_COMPILER_CLANG
         // restore FPCW
         _control87(oldFpcw, _MCW_PC);
 #endif
@@ -1625,7 +1625,7 @@
   case kmp_sch_guided_analytical_chunked: {
     T chunkspec = pr->u.p.parm1;
     UT chunkIdx;
-#if KMP_OS_WINDOWS && KMP_ARCH_X86
+#if KMP_OS_WINDOWS && KMP_ARCH_X86 && !KMP_COMPILER_CLANG
     /* for storing original FPCW value for Windows* OS on
        IA-32 architecture 8-byte version */
     unsigned int oldFpcw;
@@ -1662,7 +1662,7 @@
    Windows* OS.
    This check works around the possible effect that init != 0 for chunkIdx == 0.
  */
-#if KMP_OS_WINDOWS && KMP_ARCH_X86
+#if KMP_OS_WINDOWS && KMP_ARCH_X86 && !KMP_COMPILER_CLANG
         /* If we haven't already done so, save original
            FPCW and set precision to 64-bit, as Windows* OS
            on IA-32 architecture defaults to 53-bit */
@@ -1690,7 +1690,7 @@
         } // if
       } // if
     } // while (1)
-#if KMP_OS_WINDOWS && KMP_ARCH_X86
+#if KMP_OS_WINDOWS && KMP_ARCH_X86 && !KMP_COMPILER_CLANG
     /* restore FPCW if necessary
        AC: check fpcwSet flag first because oldFpcw can be uninitialized here
     */
Index: runtime/src/kmp_io.cpp
===================================================================
--- runtime/src/kmp_io.cpp
+++ runtime/src/kmp_io.cpp
@@ -27,11 +27,15 @@
 #include "kmp_str.h"
 
 #if KMP_OS_WINDOWS
+#if !defined(__MINGW32__)
 #pragma warning(push)
 #pragma warning(disable : 271 310)
+#endif
 #include <windows.h>
+#if !defined(__MINGW32__)
 #pragma warning(pop)
 #endif
+#endif
 
 /* ------------------------------------------------------------------------ */
 
Index: runtime/src/kmp_lock.cpp
===================================================================
--- runtime/src/kmp_lock.cpp
+++ runtime/src/kmp_lock.cpp
@@ -1716,7 +1716,7 @@
 
 /* RTM Adaptive locks */
 
-#if KMP_COMPILER_ICC && __INTEL_COMPILER >= 1300
+#if (KMP_COMPILER_ICC && __INTEL_COMPILER >= 1300) || KMP_COMPILER_CLANG
 
 #include <immintrin.h>
 #define SOFT_ABORT_MASK (_XABORT_RETRY | _XABORT_CONFLICT | _XABORT_EXPLICIT)
Index: runtime/src/kmp_os.h
===================================================================
--- runtime/src/kmp_os.h
+++ runtime/src/kmp_os.h
@@ -246,7 +246,7 @@
 
 #define KMP_EXPORT extern /* export declaration in guide libraries */
 
-#if __GNUC__ >= 4
+#if __GNUC__ >= 4 && !defined(__MINGW32__)
 #define __forceinline __inline
 #endif
 
@@ -296,7 +296,7 @@
 #define KMP_NORETURN __attribute__((noreturn))
 #endif
 
-#if KMP_OS_WINDOWS
+#if KMP_OS_WINDOWS && !defined(__GNUC__)
 #define KMP_ALIGN(bytes) __declspec(align(bytes))
 #define KMP_THREAD_LOCAL __declspec(thread)
 #define KMP_ALIAS /* Nothing */
@@ -356,10 +356,12 @@
 
 #if KMP_ASM_INTRINS && KMP_OS_WINDOWS
 
+#if !defined(__MINGW32__)
 #pragma intrinsic(InterlockedExchangeAdd)
 #pragma intrinsic(InterlockedCompareExchange)
 #pragma intrinsic(InterlockedExchange)
 #pragma intrinsic(InterlockedExchange64)
+#endif
 
 // Using InterlockedIncrement / InterlockedDecrement causes a library loading
 // ordering problem, so we use InterlockedExchangeAdd instead.
Index: runtime/src/kmp_platform.h
===================================================================
--- runtime/src/kmp_platform.h
+++ runtime/src/kmp_platform.h
@@ -82,7 +82,7 @@
 #define KMP_ARCH_MIPS64 0
 
 #if KMP_OS_WINDOWS
-#if defined _M_AMD64
+#if defined(_M_AMD64) || defined(__x86_64)
 #undef KMP_ARCH_X86_64
 #define KMP_ARCH_X86_64 1
 #else
Index: runtime/src/kmp_safe_c_api.h
===================================================================
--- runtime/src/kmp_safe_c_api.h
+++ runtime/src/kmp_safe_c_api.h
@@ -15,7 +15,7 @@
 
 // Not every unsafe call listed here is handled now, but keeping everything
 // in one place should be handy for future maintenance.
-#if KMP_OS_WINDOWS
+#if KMP_OS_WINDOWS && !defined(__MINGW32__)
 
 #define RSIZE_MAX_STR (4UL << 10) // 4KB
 
Index: runtime/src/kmp_settings.cpp
===================================================================
--- runtime/src/kmp_settings.cpp
+++ runtime/src/kmp_settings.cpp
@@ -5517,7 +5517,7 @@
           for (int bit = init_mask->begin(); bit != init_mask->end();
                bit = init_mask->next(bit))
             num_bits_in_mask++;
-          exactly_one_group = (num_bits_in_group == num_bits_in_mask);
+          exactly_one_group = (num_bits_in_group == static_cast<DWORD>(num_bits_in_mask));
         }
         KMP_CPU_FREE(init_mask);
       }
Index: runtime/src/kmp_utility.cpp
===================================================================
--- runtime/src/kmp_utility.cpp
+++ runtime/src/kmp_utility.cpp
@@ -375,7 +375,11 @@
         case 'I':
         case 'i': {
           pid_t id = getpid();
+#if KMP_ARCH_X86_64 && defined(__MINGW32__)
+          snp_result = KMP_SNPRINTF(pos, end - pos + 1, "%0*lld", width, id);
+#else
           snp_result = KMP_SNPRINTF(pos, end - pos + 1, "%0*d", width, id);
+#endif
           if (snp_result >= 0 && snp_result <= end - pos) {
             while (*pos)
               ++pos;
Index: runtime/src/kmp_wrapper_getpid.h
===================================================================
--- runtime/src/kmp_wrapper_getpid.h
+++ runtime/src/kmp_wrapper_getpid.h
@@ -39,7 +39,9 @@
 // "process.h".
 #include <process.h>
 // Let us simulate Unix.
+#ifndef __MINGW32__
 typedef int pid_t;
+#endif
 #define getpid _getpid
 #define __kmp_gettid() GetCurrentThreadId()
 
Index: runtime/src/kmp_wrapper_malloc.h
===================================================================
--- runtime/src/kmp_wrapper_malloc.h
+++ runtime/src/kmp_wrapper_malloc.h
@@ -93,7 +93,9 @@
 // Include alloca() declaration.
 #if KMP_OS_WINDOWS
 #include <malloc.h> // Windows* OS: _alloca() declared in "malloc.h".
+#ifndef __MINGW32__
 #define alloca _alloca // Allow to use alloca() with no underscore.
+#endif
 #elif KMP_OS_FREEBSD || KMP_OS_NETBSD
 // Declared in "stdlib.h".
 #elif KMP_OS_UNIX
Index: runtime/src/libomp.rc.var
===================================================================
--- runtime/src/libomp.rc.var
+++ runtime/src/libomp.rc.var
@@ -11,7 +11,7 @@
 ////===----------------------------------------------------------------------===//
 //
 
-#include "winres.h"
+#include "winresrc.h"
 #include "kmp_config.h"
 
 LANGUAGE LANG_ENGLISH, SUBLANG_ENGLISH_US    // English (U.S.) resources
Index: runtime/src/thirdparty/ittnotify/ittnotify_static.c
===================================================================
--- runtime/src/thirdparty/ittnotify/ittnotify_static.c
+++ runtime/src/thirdparty/ittnotify/ittnotify_static.c
@@ -12,7 +12,11 @@
 #include "ittnotify_config.h"
 
 #if ITT_PLATFORM==ITT_PLATFORM_WIN
+#if defined(__MINGW32__)
+#include <limits.h>
+#else
 #define PATH_MAX 512
+#endif
 #else /* ITT_PLATFORM!=ITT_PLATFORM_WIN */
 #include <limits.h>
 #include <dlfcn.h>
@@ -28,7 +32,9 @@
 #include "ittnotify.h"
 #include "legacy/ittnotify.h"
 
+#if !defined(__MINGW32__)
 #include "disable_warnings.h"
+#endif
 
 static const char api_version[] = API_VERSION "\0\n@(#) $Revision: 481659 $\n";
 
@@ -190,7 +196,7 @@
 
 #pragma pack(pop)
 
-#if ITT_PLATFORM==ITT_PLATFORM_WIN
+#if ITT_PLATFORM==ITT_PLATFORM_WIN && !defined(__MINGW32__)
 #pragma warning(push)
 #pragma warning(disable: 4054) /* warning C4054: 'type cast' : from function pointer 'XXX' to data pointer 'void *' */
 #endif /* ITT_PLATFORM==ITT_PLATFORM_WIN */
@@ -213,7 +219,7 @@
     {NULL, NULL, NULL, NULL, __itt_group_none}
 };
 
-#if ITT_PLATFORM==ITT_PLATFORM_WIN
+#if ITT_PLATFORM==ITT_PLATFORM_WIN && !defined(__MINGW32__)
 #pragma warning(pop)
 #endif /* ITT_PLATFORM==ITT_PLATFORM_WIN */
 
@@ -248,7 +254,7 @@
 ITT_EXTERN_C void _N_(error_handler)(__itt_error_code, va_list args);
 #endif /* ITT_NOTIFY_EXT_REPORT */
 
-#if ITT_PLATFORM==ITT_PLATFORM_WIN
+#if ITT_PLATFORM==ITT_PLATFORM_WIN && !defined(__MINGW32__)
 #pragma warning(push)
 #pragma warning(disable: 4055) /* warning C4055: 'type cast' : from data pointer 'void *' to function pointer 'XXX' */
 #endif /* ITT_PLATFORM==ITT_PLATFORM_WIN */
@@ -274,7 +280,7 @@
     va_end(args);
 }
 
-#if ITT_PLATFORM==ITT_PLATFORM_WIN
+#if ITT_PLATFORM==ITT_PLATFORM_WIN && !defined(__MINGW32__)
 #pragma warning(pop)
 #endif /* ITT_PLATFORM==ITT_PLATFORM_WIN */
 
@@ -1009,7 +1015,7 @@
         *_N_(_ittapi_global).api_list_ptr[i].func_ptr = _N_(_ittapi_global).api_list_ptr[i].null_func;
 }
 
-#if ITT_PLATFORM==ITT_PLATFORM_WIN
+#if ITT_PLATFORM==ITT_PLATFORM_WIN && !defined(__MINGW32__)
 #pragma warning(push)
 #pragma warning(disable: 4054) /* warning C4054: 'type cast' : from function pointer 'XXX' to data pointer 'void *' */
 #pragma warning(disable: 4055) /* warning C4055: 'type cast' : from data pointer 'void *' to function pointer 'XXX' */
@@ -1187,7 +1193,7 @@
     return prev;
 }
 
-#if ITT_PLATFORM==ITT_PLATFORM_WIN
+#if ITT_PLATFORM==ITT_PLATFORM_WIN && !defined(__MINGW32__)
 #pragma warning(pop)
 #endif /* ITT_PLATFORM==ITT_PLATFORM_WIN */
 
Index: runtime/src/z_Windows_NT_util.cpp
===================================================================
--- runtime/src/z_Windows_NT_util.cpp
+++ runtime/src/z_Windows_NT_util.cpp
@@ -887,6 +887,7 @@
   return 1e9 * __kmp_win32_tick * now.QuadPart;
 }
 
+extern "C"
 void *__stdcall __kmp_launch_worker(void *arg) {
   volatile void *stack_data;
   void *exit_val;