[Local] Delete a redundant check. NFC

isInstructionTriviallyDead also performs the use_empty() check.

llvm-svn: 353637
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 062bbcd..933a69c 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -429,7 +429,7 @@
 bool llvm::RecursivelyDeleteTriviallyDeadInstructions(
     Value *V, const TargetLibraryInfo *TLI, MemorySSAUpdater *MSSAU) {
   Instruction *I = dyn_cast<Instruction>(V);
-  if (!I || !I->use_empty() || !isInstructionTriviallyDead(I, TLI))
+  if (!I || !isInstructionTriviallyDead(I, TLI))
     return false;
 
   SmallVector<Instruction*, 16> DeadInsts;