[PATCH] This patch introduces MemorySSA, a virtual SSA form for memory.Details on what it looks like are in MemorySSA.h

[Sanjoy Das]

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Comment at: lib/Transforms/Utils/MemorySSA.cpp:151
@@ +150,3 @@
+  // In both of these cases, we should arrive at the same version
+  // number for all arguments. If we don't. we can't ignore this phi
+  // node, because this means at least one of the arguments has a
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Nit: should probably be `If we don't, we can't`

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Comment at: lib/Transforms/Utils/MemorySSA.cpp:205
@@ +204,3 @@
+      MemoryAccess *Arg = P->getIncomingValue(i);
+      if (Arg == DominatingArg)
+        continue;
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A very basic question:  why do we need to treat the most dominating input to the memory PHI node specially?  Why not just check if every input agrees on the clobbering instruction?

http://reviews.llvm.org/D7864

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