[NVPTX] Infer __nvvm_reflect as nounwind, readnone

This patch simply mirrors the attributes we give to @llvm.nvvm.reflect
to the __nvvm_reflect libdevice call.  This shaves about 30% of the code
in libdevice away because of CSE opportunities.  It's also helps us
figure out that libdevice implementations of transcendental functions
don't have side-effects.

llvm-svn: 265060

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/Analysis/TargetLibraryInfo.cpp b/llvm/lib/Analysis/TargetLibraryInfo.cpp
index 3bd54c47e60..ab667ab7b6a 100644
--- a/llvm/lib/Analysis/TargetLibraryInfo.cpp
+++ b/llvm/lib/Analysis/TargetLibraryInfo.cpp
@@ -396,8 +396,12 @@ static void initialize(TargetLibraryInfoImpl &TLI, const Triple &T,
   //
   // FIXME: Having no standard library prevents e.g. many fastmath
   // optimizations, so this situation should be fixed.
-  if (T.isNVPTX())
+  if (T.isNVPTX()) {
     TLI.disableAllFunctions();
+    TLI.setAvailable(LibFunc::nvvm_reflect);
+  } else {
+    TLI.setUnavailable(LibFunc::nvvm_reflect);
+  }
 
   TLI.addVectorizableFunctionsFromVecLib(ClVectorLibrary);
 }