InstCombine: Fix a crasher when encountering a function pointer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162180 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index c43fb71..c3fc18c 100644
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2990,7 +2990,7 @@
         CallInst *CI = cast<CallInst>(LHSI);
         LibFunc::Func Func;
         // Various optimization for fabs compared with zero.
-        if (RHSC->isNullValue() &&
+        if (RHSC->isNullValue() && CI->getCalledFunction() &&
             TLI->getLibFunc(CI->getCalledFunction()->getName(), Func) &&
             TLI->has(Func)) {
           if (Func == LibFunc::fabs || Func == LibFunc::fabsf ||