Replace size method call of containers to empty method where appropriate

This patch was generated by a clang tidy checker that is being open sourced.
The documentation of that checker is the following:

/// The emptiness of a container should be checked using the empty method
/// instead of the size method. It is not guaranteed that size is a
/// constant-time function, and it is generally more efficient and also shows
/// clearer intent to use empty. Furthermore some containers may implement the
/// empty method but not implement the size method. Using empty whenever
/// possible makes it easier to switch to another container in the future.

Patch by Gábor Horváth!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226161 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -3549,7 +3549,7 @@ bool LoopVectorizationLegality::canVectorize() {
   }
 
   // We can only vectorize innermost loops.
-  if (TheLoop->getSubLoopsVector().size()) {
+  if (!TheLoop->getSubLoopsVector().empty()) {
     emitAnalysis(Report() << "loop is not the innermost loop");
     return false;
   }
@@ -4011,7 +4011,7 @@ void LoopVectorizationLegality::collectLoopUniforms() {
       if (I->getType()->isPointerTy() && isConsecutivePtr(I))
         Worklist.insert(Worklist.end(), I->op_begin(), I->op_end());
 
-  while (Worklist.size()) {
+  while (!Worklist.empty()) {
     Instruction *I = dyn_cast<Instruction>(Worklist.back());
     Worklist.pop_back();