[AArch64] Remove SLI/SRI debug. NFC

We don't usually have special debug for DAG combines, and this one has been
around long enough to not be required any more.

Author: davemgreen

llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

@@ -108,7 +108,6 @@ using namespace llvm::PatternMatch;
 #define DEBUG_TYPE "aarch64-lower"
 
 STATISTIC(NumTailCalls, "Number of tail calls");
-STATISTIC(NumShiftInserts, "Number of vector shift inserts");
 STATISTIC(NumOptimizedImms, "Number of times immediates were optimized");
 
 // FIXME: The necessary dtprel relocations don't seem to be supported
@@ -14581,12 +14580,6 @@ static SDValue tryLowerToSLI(SDNode *N, SelectionDAG &DAG) {
   unsigned Inst = IsShiftRight ? AArch64ISD::VSRI : AArch64ISD::VSLI;
   SDValue ResultSLI = DAG.getNode(Inst, DL, VT, X, Y, Imm);
 
-  LLVM_DEBUG(dbgs() << "aarch64-lower: transformed: \n");
-  LLVM_DEBUG(N->dump(&DAG));
-  LLVM_DEBUG(dbgs() << "into: \n");
-  LLVM_DEBUG(ResultSLI->dump(&DAG));
-
-  ++NumShiftInserts;
   return ResultSLI;
 }