[llvm][SROA] Replace calls to Type::getPointerTo (NFC)

NFC cleanup towards removing method Type::getPointerTo.

* Remove unnecessary call to Type::getPointerTo
* Replace call to Type::getPointerTo with IRB.getPtrTy

Author: JOE1994

llvm/lib/Transforms/Scalar/SROA.cpp

@@ -2879,7 +2879,7 @@ class AllocaSliceRewriter : public InstVisitor<AllocaSliceRewriter, bool> {
                                 "endian_shift");
           }
     } else {
-      Type *LTy = TargetTy->getPointerTo(AS);
+      Type *LTy = IRB.getPtrTy(AS);
       LoadInst *NewLI =
           IRB.CreateAlignedLoad(TargetTy, getNewAllocaSlicePtr(IRB, LTy),
                                 getSliceAlign(), LI.isVolatile(), LI.getName());
@@ -2909,9 +2909,9 @@ class AllocaSliceRewriter : public InstVisitor<AllocaSliceRewriter, bool> {
       // basis for the new value. This allows us to replace the uses of LI with
       // the computed value, and then replace the placeholder with LI, leaving
       // LI only used for this computation.
-      Value *Placeholder = new LoadInst(
-          LI.getType(), PoisonValue::get(LI.getType()->getPointerTo(AS)), "",
-          false, Align(1));
+      Value *Placeholder =
+          new LoadInst(LI.getType(), PoisonValue::get(IRB.getPtrTy(AS)), "",
+                       false, Align(1));
       V = insertInteger(DL, IRB, Placeholder, V, NewBeginOffset - BeginOffset,
                         "insert");
       LI.replaceAllUsesWith(V);
@@ -3034,7 +3034,7 @@ class AllocaSliceRewriter : public InstVisitor<AllocaSliceRewriter, bool> {
           IRB.CreateAlignedStore(V, NewPtr, NewAI.getAlign(), SI.isVolatile());
     } else {
       unsigned AS = SI.getPointerAddressSpace();
-      Value *NewPtr = getNewAllocaSlicePtr(IRB, V->getType()->getPointerTo(AS));
+      Value *NewPtr = getNewAllocaSlicePtr(IRB, IRB.getPtrTy(AS));
       NewSI =
           IRB.CreateAlignedStore(V, NewPtr, getSliceAlign(), SI.isVolatile());
     }
@@ -3389,7 +3389,6 @@ class AllocaSliceRewriter : public InstVisitor<AllocaSliceRewriter, bool> {
     } else {
       OtherTy = NewAllocaTy;
     }
-    OtherPtrTy = OtherTy->getPointerTo(OtherAS);
 
     Value *AdjPtr = getAdjustedPtr(IRB, DL, OtherPtr, OtherOffset, OtherPtrTy,
                                    OtherPtr->getName() + ".");