[AArch64] Gangup loads and stores for pairing.

Keep loads and stores together (target defines how many loads
and stores to gang up), such that it will help in pairing
and vectorization.

Differential Revision https://reviews.llvm.org/D46477

llvm-svn: 332482
diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index e18a6ab..3a2036b 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -535,6 +535,7 @@
   // Perform these initializations only once.
   MaxStoresPerMemset = MaxStoresPerMemcpy = MaxStoresPerMemmove =
       MaxLoadsPerMemcmp = 8;
+  MaxGluedStoresPerMemcpy = 0;
   MaxStoresPerMemsetOptSize = MaxStoresPerMemcpyOptSize =
       MaxStoresPerMemmoveOptSize = MaxLoadsPerMemcmpOptSize = 4;
   UseUnderscoreSetJmp = false;