Index: llvm/trunk/lib/Analysis/TargetLibraryInfo.cpp
===================================================================
--- llvm/trunk/lib/Analysis/TargetLibraryInfo.cpp
+++ llvm/trunk/lib/Analysis/TargetLibraryInfo.cpp
@@ -385,6 +385,20 @@
     TLI.setUnavailable(LibFunc::tmpfile64);
   }
 
+  // As currently implemented in clang, NVPTX code has no standard library to
+  // speak of.  Headers provide a standard-ish library implementation, but many
+  // of the signatures are wrong -- for example, many libm functions are not
+  // extern "C".
+  //
+  // libdevice, an IR library provided by nvidia, is linked in by the front-end,
+  // but only used functions are provided to llvm.  Moreover, most of the
+  // functions in libdevice don't map precisely to standard library functions.
+  //
+  // FIXME: Having no standard library prevents e.g. many fastmath
+  // optimizations, so this situation should be fixed.
+  if (T.isNVPTX())
+    TLI.disableAllFunctions();
+
   TLI.addVectorizableFunctionsFromVecLib(ClVectorLibrary);
 }