Add missing file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133717 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/FEnv.h

@@ -0,0 +1,56 @@
+//===- llvm/Support/FEnv.h - Host floating-point exceptions ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides an operating system independent interface to
+// floating-point exception interfaces.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SYSTEM_FENV_H
+#define LLVM_SYSTEM_FENV_H
+
+#include "llvm/Config/config.h"
+#include <cerrno>
+#ifdef HAVE_FENV_H
+#include <fenv.h>
+#endif
+
+// FIXME: Clang's #include handling apparently doesn't work for libstdc++'s
+// fenv.h; see PR6907 for details.
+#if defined(__clang__) && defined(_GLIBCXX_FENV_H)
+#undef HAVE_FENV_H
+#endif
+
+namespace llvm {
+namespace sys {
+
+/// llvm_fenv_clearexcept - Clear the floating-point exception state.
+static inline void llvm_fenv_clearexcept() {
+#ifdef HAVE_FENV_H
+  feclearexcept(FE_ALL_EXCEPT);
+#endif
+  errno = 0;
+}
+
+/// llvm_fenv_testexcept - Test if a floating-point exception was raised.
+static inline bool llvm_fenv_testexcept() {
+  int errno_val = errno;
+  if (errno_val == ERANGE || errno_val == EDOM)
+    return true;
+#ifdef HAVE_FENV_H
+  if (fetestexcept(FE_ALL_EXCEPT & ~FE_INEXACT))
+    return true;
+#endif
+  return false;
+}
+
+} // End sys namespace
+} // End llvm namespace
+
+#endif