AMDGPU: mark {exp,log}10{,f,l} library functions as unavailable

Summary:
The SimplifyLibCalls part of InstCombine generates calls to those otherwise.

I wonder if at some point we shouldn't just call disableAllFunctions() and
then enable functions on a whitelist basis...

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96495

Reviewers: arsenm, tstellarAMD

Subscribers: llvm-commits, kzhuravl

Differential Revision: http://reviews.llvm.org/D21282

llvm-svn: 272664
diff --git a/llvm/lib/Analysis/TargetLibraryInfo.cpp b/llvm/lib/Analysis/TargetLibraryInfo.cpp
index 68b0764..789b039 100644
--- a/llvm/lib/Analysis/TargetLibraryInfo.cpp
+++ b/llvm/lib/Analysis/TargetLibraryInfo.cpp
@@ -65,6 +65,12 @@
     TLI.setUnavailable(LibFunc::ldexp);
     TLI.setUnavailable(LibFunc::ldexpf);
     TLI.setUnavailable(LibFunc::ldexpl);
+    TLI.setUnavailable(LibFunc::exp10);
+    TLI.setUnavailable(LibFunc::exp10f);
+    TLI.setUnavailable(LibFunc::exp10l);
+    TLI.setUnavailable(LibFunc::log10);
+    TLI.setUnavailable(LibFunc::log10f);
+    TLI.setUnavailable(LibFunc::log10l);
   }
 
   // There are no library implementations of mempcy and memset for AMD gpus and