Revert "AMDGPU: Fix runtime unrolling when cascaded GEPs present (llvm#147700)" (#1348)

Author: JeniferC99

llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp

@@ -217,13 +217,10 @@ void AMDGPUTTIImpl::getUnrollingPreferences(
         // a variable, most likely we will be unable to combine it.
         // Do not unroll too deep inner loops for local memory to give a chance
         // to unroll an outer loop for a more important reason.
-        if (LocalGEPsSeen > 1 || L->getLoopDepth() > 2)
+        if (LocalGEPsSeen > 1 || L->getLoopDepth() > 2 ||
+            (!isa<GlobalVariable>(GEP->getPointerOperand()) &&
+             !isa<Argument>(GEP->getPointerOperand())))
           continue;
-
-        const Value *V = getUnderlyingObject(GEP->getPointerOperand());
-        if (!isa<GlobalVariable>(V) && !isa<Argument>(V))
-          continue;
-
         LLVM_DEBUG(dbgs() << "Allow unroll runtime for loop:\n"
                           << *L << " due to LDS use.\n");
         UP.Runtime = UnrollRuntimeLocal;