[CVP] Preserve exact name when converting sext->zext and ashr->lshr.

[craig.topper]

Summary

Previously we took the old name and always appended a numberic suffix.
Since we're doing a 1:1 replacement, it's clearer to keep the original
name exactly.

[fhahn]

LGTM, thanks!

llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp

if (NegOneOrZero.contains(LRange)) {
     return true;
   }
 
   if (!isNonNegative(SDI->getOperand(0), LVI, SDI))
     return false;
 
   ++NumAShrsConverted;
   auto *BO = BinaryOperator::CreateLShr(SDI->getOperand(0), SDI->getOperand(1),
-                                        SDI->getName(), SDI);
+                                        "", SDI);
+  BO->takeName(SDI);
   BO->setDebugLoc(SDI->getDebugLoc());
   BO->setIsExact(SDI->isExact());
   SDI->replaceAllUsesWith(BO);
   SDI->eraseFromParent();
 
   return true;
 }
 
 static bool processSExt(SExtInst *SDI, LazyValueInfo *LVI) {
   if (SDI->getType()->isVectorTy())
     return false;
 
   Value *Base = SDI->getOperand(0);
 
   if (!isNonNegative(Base, LVI, SDI))
     return false;
 
   ++NumSExt;
-  auto *ZExt =
-      CastInst::CreateZExtOrBitCast(Base, SDI->getType(), SDI->getName(), SDI);
+  auto *ZExt = CastInst::CreateZExtOrBitCast(Base, SDI->getType(), "", SDI);
+  ZExt->takeName(SDI);
   ZExt->setDebugLoc(SDI->getDebugLoc());
   SDI->replaceAllUsesWith(ZExt);
   SDI->eraseFromParent();
 
   return true;
 }
 
 static bool processBinOp(BinaryOperator *BinOp, LazyValueInfo *LVI) {