[Lint] Upgrade uses of MemoryIntrinic::getAlignment() to new API. (NFCI)

Summary:
  This change is part of step five in the series of changes to remove alignment argument from
memcpy/memmove/memset in favour of alignment attributes. In particular, this changes the Lint
analysis to cease using the old getAlignment() API of MemoryIntrinsic in favour of getting
source & dest specific alignments through the new API.

Steps:
Step 1) Remove alignment parameter and create alignment parameter attributes for
memcpy/memmove/memset. ( rL322965, rC322964, rL322963 )
Step 2) Expand the IRBuilder API to allow creation of memcpy/memmove with differing
source and dest alignments. ( rL323597 )
Step 3) Update Clang to use the new IRBuilder API. ( rC323617 )
Step 4) Update Polly to use the new IRBuilder API. ( rL323618 )
Step 5) Update LLVM passes that create memcpy/memmove calls to use the new IRBuilder API,
and those that use use MemIntrinsicInst::[get|set]Alignment() to use [get|set]DestAlignment()
and [get|set]SourceAlignment() instead.
Step 6) Remove the single-alignment IRBuilder API for memcpy/memmove, and the
MemIntrinsicInst::[get|set]Alignment() methods.

Reference
   http://lists.llvm.org/pipermail/llvm-dev/2015-August/089384.html
   http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html

llvm-svn: 323886
diff --git a/llvm/lib/Analysis/Lint.cpp b/llvm/lib/Analysis/Lint.cpp
index 0e3f498..327f09a 100644
--- a/llvm/lib/Analysis/Lint.cpp
+++ b/llvm/lib/Analysis/Lint.cpp
@@ -323,9 +323,9 @@
       MemCpyInst *MCI = cast<MemCpyInst>(&I);
       // TODO: If the size is known, use it.
       visitMemoryReference(I, MCI->getDest(), MemoryLocation::UnknownSize,
-                           MCI->getAlignment(), nullptr, MemRef::Write);
+                           MCI->getDestAlignment(), nullptr, MemRef::Write);
       visitMemoryReference(I, MCI->getSource(), MemoryLocation::UnknownSize,
-                           MCI->getAlignment(), nullptr, MemRef::Read);
+                           MCI->getSourceAlignment(), nullptr, MemRef::Read);
 
       // Check that the memcpy arguments don't overlap. The AliasAnalysis API
       // isn't expressive enough for what we really want to do. Known partial
@@ -345,16 +345,16 @@
       MemMoveInst *MMI = cast<MemMoveInst>(&I);
       // TODO: If the size is known, use it.
       visitMemoryReference(I, MMI->getDest(), MemoryLocation::UnknownSize,
-                           MMI->getAlignment(), nullptr, MemRef::Write);
+                           MMI->getDestAlignment(), nullptr, MemRef::Write);
       visitMemoryReference(I, MMI->getSource(), MemoryLocation::UnknownSize,
-                           MMI->getAlignment(), nullptr, MemRef::Read);
+                           MMI->getSourceAlignment(), nullptr, MemRef::Read);
       break;
     }
     case Intrinsic::memset: {
       MemSetInst *MSI = cast<MemSetInst>(&I);
       // TODO: If the size is known, use it.
       visitMemoryReference(I, MSI->getDest(), MemoryLocation::UnknownSize,
-                           MSI->getAlignment(), nullptr, MemRef::Write);
+                           MSI->getDestAlignment(), nullptr, MemRef::Write);
       break;
     }