[InstCombine] Remove redundant icmp gep fold (NFCI)

Gep with zero indices will be folded away independently. It will
only be retained for splat geps, for which the transform is not
applicable anyway.

Author: nikic

llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

@@ -3952,14 +3952,6 @@ Instruction *InstCombinerImpl::foldICmpInstWithConstantNotInt(ICmpInst &I) {
     return nullptr;
 
   switch (LHSI->getOpcode()) {
-  case Instruction::GetElementPtr:
-    // icmp pred GEP (P, int 0, int 0, int 0), null -> icmp pred P, null
-    if (RHSC->isNullValue() &&
-        cast<GetElementPtrInst>(LHSI)->hasAllZeroIndices())
-      return new ICmpInst(
-          I.getPredicate(), LHSI->getOperand(0),
-          Constant::getNullValue(LHSI->getOperand(0)->getType()));
-    break;
   case Instruction::PHI:
     if (Instruction *NV = foldOpIntoPhi(I, cast<PHINode>(LHSI)))
       return NV;