[SLP] remove uses of 'auto' that obscure functionality; NFC

Author: rotateright

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -6817,9 +6817,9 @@ class HorizontalReduction {
     Builder.setFastMathFlags(Unsafe);
 
     BoUpSLP::ExtraValueToDebugLocsMap ExternallyUsedValues;
-    // The same extra argument may be used several time, so log each attempt
+    // The same extra argument may be used several times, so log each attempt
     // to use it.
-    for (auto &Pair : ExtraArgs) {
+    for (std::pair<Instruction *, Value *> &Pair : ExtraArgs) {
       assert(Pair.first && "DebugLoc must be set.");
       ExternallyUsedValues[Pair.second].push_back(Pair.first);
     }
@@ -6844,7 +6844,7 @@ class HorizontalReduction {
 
     unsigned i = 0;
     while (i < NumReducedVals - ReduxWidth + 1 && ReduxWidth > 2) {
-      auto VL = makeArrayRef(&ReducedVals[i], ReduxWidth);
+      ArrayRef<Value *> VL = makeArrayRef(&ReducedVals[i], ReduxWidth);
       V.buildTree(VL, ExternallyUsedValues, IgnoreList);
       Optional<ArrayRef<unsigned>> Order = V.bestOrder();
       // TODO: Handle orders of size less than number of elements in the vector.