fix typos; NFC

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253359 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/InstCombine/InstCombineCasts.cpp

@@ -501,15 +501,15 @@ Instruction *InstCombiner::visitTrunc(TruncInst &CI) {
   // Transform trunc(lshr (sext A), Cst) to ashr A, Cst to eliminate type
   // conversion.
   // It works because bits coming from sign extension have the same value as
-  // sign bit of the original value; performing ashr instead of lshr
+  // the sign bit of the original value; performing ashr instead of lshr
   // generates bits of the same value as the sign bit.
   if (Src->hasOneUse() &&
       match(Src, m_LShr(m_SExt(m_Value(A)), m_ConstantInt(Cst))) &&
       cast<Instruction>(Src)->getOperand(0)->hasOneUse()) {
     const unsigned ASize = A->getType()->getPrimitiveSizeInBits();
     // This optimization can be only performed when zero bits generated by
     // the original lshr aren't pulled into the value after truncation, so we
-    // can only shift by values smaller then the size of destination type (in
+    // can only shift by values smaller than the size of destination type (in
     // bits).
     if (Cst->getValue().ult(ASize)) {
       Value *Shift = Builder->CreateAShr(A, Cst->getZExtValue());