2 files changed, 9 insertions, 13 deletions
diff --git a/src/Makefile.leveldb.include b/src/Makefile.leveldb.include
index ac38141f43..833f3d2a10 100644
--- a/src/Makefile.leveldb.include
+++ b/src/Makefile.leveldb.include
@@ -142,7 +142,7 @@ leveldb_libmemenv_a_SOURCES += leveldb/helpers/memenv/memenv.h
 
 leveldb_libleveldb_sse42_a_CPPFLAGS = $(leveldb_libleveldb_a_CPPFLAGS)
 leveldb_libleveldb_sse42_a_CXXFLAGS = $(leveldb_libleveldb_a_CXXFLAGS)
-if ENABLE_SSE42
+if ENABLE_HWCRC32
 leveldb_libleveldb_sse42_a_CPPFLAGS += -DLEVELDB_PLATFORM_POSIX_SSE
 leveldb_libleveldb_sse42_a_CXXFLAGS += $(SSE42_CXXFLAGS)
 endif
diff --git a/src/validation.cpp b/src/validation.cpp
index ddc8b1b964..bcc158c504 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -532,24 +532,20 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
         CCoinsViewMemPool viewMemPool(pcoinsTip, pool);
         view.SetBackend(viewMemPool);
 
-        // do we already have it?
-        for (size_t out = 0; out < tx.vout.size(); out++) {
-            COutPoint outpoint(hash, out);
-            bool had_coin_in_cache = pcoinsTip->HaveCoinInCache(outpoint);
-            if (view.HaveCoin(outpoint)) {
-                if (!had_coin_in_cache) {
-                    coins_to_uncache.push_back(outpoint);
-                }
-                return state.Invalid(false, REJECT_DUPLICATE, "txn-already-known");
-            }
-        }
-
         // do all inputs exist?
         for (const CTxIn txin : tx.vin) {
             if (!pcoinsTip->HaveCoinInCache(txin.prevout)) {
                 coins_to_uncache.push_back(txin.prevout);
             }
             if (!view.HaveCoin(txin.prevout)) {
+                // Are inputs missing because we already have the tx?
+                for (size_t out = 0; out < tx.vout.size(); out++) {
+                    // Optimistically just do efficient check of cache for outputs
+                    if (pcoinsTip->HaveCoinInCache(COutPoint(hash, out))) {
+                        return state.Invalid(false, REJECT_DUPLICATE, "txn-already-known");
+                    }
+                }
+                // Otherwise assume this might be an orphan tx for which we just haven't seen parents yet
                 if (pfMissingInputs) {
                     *pfMissingInputs = true;
                 }