[DAG] ISD::is*Load/is*Store - merge isa<>/cast<> calls into single dyn_cast<>. NFCI.

cast<> repeats most of the work that isa<> will have already done (and even calls assert(isa<>) in debug builds) - just use dyn_cast and a pointer check to avoid all this duplicated work.

Author: RKSimon

llvm/include/llvm/CodeGen/SelectionDAGNodes.h

@@ -3080,53 +3080,53 @@ namespace ISD {
 
   /// Returns true if the specified node is a non-extending and unindexed load.
   inline bool isNormalLoad(const SDNode *N) {
-    const LoadSDNode *Ld = dyn_cast<LoadSDNode>(N);
+    auto *Ld = dyn_cast<LoadSDNode>(N);
     return Ld && Ld->getExtensionType() == ISD::NON_EXTLOAD &&
-      Ld->getAddressingMode() == ISD::UNINDEXED;
+           Ld->getAddressingMode() == ISD::UNINDEXED;
   }
 
   /// Returns true if the specified node is a non-extending load.
   inline bool isNON_EXTLoad(const SDNode *N) {
-    return isa<LoadSDNode>(N) &&
-      cast<LoadSDNode>(N)->getExtensionType() == ISD::NON_EXTLOAD;
+    auto *Ld = dyn_cast<LoadSDNode>(N);
+    return Ld && Ld->getExtensionType() == ISD::NON_EXTLOAD;
   }
 
   /// Returns true if the specified node is a EXTLOAD.
   inline bool isEXTLoad(const SDNode *N) {
-    return isa<LoadSDNode>(N) &&
-      cast<LoadSDNode>(N)->getExtensionType() == ISD::EXTLOAD;
+    auto *Ld = dyn_cast<LoadSDNode>(N);
+    return Ld && Ld->getExtensionType() == ISD::EXTLOAD;
   }
 
   /// Returns true if the specified node is a SEXTLOAD.
   inline bool isSEXTLoad(const SDNode *N) {
-    return isa<LoadSDNode>(N) &&
-      cast<LoadSDNode>(N)->getExtensionType() == ISD::SEXTLOAD;
+    auto *Ld = dyn_cast<LoadSDNode>(N);
+    return Ld && Ld->getExtensionType() == ISD::SEXTLOAD;
   }
 
   /// Returns true if the specified node is a ZEXTLOAD.
   inline bool isZEXTLoad(const SDNode *N) {
-    return isa<LoadSDNode>(N) &&
-      cast<LoadSDNode>(N)->getExtensionType() == ISD::ZEXTLOAD;
+    auto *Ld = dyn_cast<LoadSDNode>(N);
+    return Ld && Ld->getExtensionType() == ISD::ZEXTLOAD;
   }
 
   /// Returns true if the specified node is an unindexed load.
   inline bool isUNINDEXEDLoad(const SDNode *N) {
-    return isa<LoadSDNode>(N) &&
-      cast<LoadSDNode>(N)->getAddressingMode() == ISD::UNINDEXED;
+    auto *Ld = dyn_cast<LoadSDNode>(N);
+    return Ld && Ld->getAddressingMode() == ISD::UNINDEXED;
   }
 
   /// Returns true if the specified node is a non-truncating
   /// and unindexed store.
   inline bool isNormalStore(const SDNode *N) {
-    const StoreSDNode *St = dyn_cast<StoreSDNode>(N);
+    auto *St = dyn_cast<StoreSDNode>(N);
     return St && !St->isTruncatingStore() &&
-      St->getAddressingMode() == ISD::UNINDEXED;
+           St->getAddressingMode() == ISD::UNINDEXED;
   }
 
   /// Returns true if the specified node is an unindexed store.
   inline bool isUNINDEXEDStore(const SDNode *N) {
-    return isa<StoreSDNode>(N) &&
-      cast<StoreSDNode>(N)->getAddressingMode() == ISD::UNINDEXED;
+    auto *St = dyn_cast<StoreSDNode>(N);
+    return St && St->getAddressingMode() == ISD::UNINDEXED;
   }
 
   /// Attempt to match a unary predicate against a scalar/splat constant or