Index: lib/Transforms/Vectorize/LoopVectorizationLegality.cpp
===================================================================
--- lib/Transforms/Vectorize/LoopVectorizationLegality.cpp
+++ lib/Transforms/Vectorize/LoopVectorizationLegality.cpp
@@ -715,7 +715,9 @@
           !(CI->getCalledFunction() && TLI &&
             TLI->isFunctionVectorizable(CI->getCalledFunction()->getName()))) {
         ORE->emit(createMissedAnalysis("CantVectorizeCall", CI)
-                  << "call instruction cannot be vectorized");
+                  << "call instruction cannot be vectorized "
+                     "(if this is a math library call, consider relaxing the "
+                     "floating-point model)");
         LLVM_DEBUG(
             dbgs() << "LV: Found a non-intrinsic, non-libfunc callsite.\n");
         return false;