MarkForSerialization now ignores duplicated uses

Remove the logic for detecting Instructions with duplicated uses
introduced by control-flow restructuring (the use is duplicated, but the
instruction is not).
By dropping this detection, we'll end up not marking for serialization
some Instructions. Hence, when emitting C code, such Instructions will
just be emitted as inline expressions, without declaring a dedicated
local variable to hold their value. This is somehow suboptimal w.r.t the
fact that the expression will be emitted many times, one for each
duplicated use. However, this is not semantically incorrect, just
verbose.

On the other hand, the logic for detecting Instructions with duplicated
uses has always been subtly broken, because it only looked at the number
of duplicates for a given basic block introduced by control-flow
restructuring.
This information is not enough to detect Instructions with duplicated
uses. Proper detection should actually be based on GHAST.

lib/MarkForSerialization/MarkForSerializationPass.cpp

@@ -39,16 +39,9 @@ bool MarkForSerializationPass::runOnFunction(llvm::Function &F) {
     if (not F.getName().equals(TargetFunction.c_str()))
       return false;
 
-  // Compute the number of duplicates for each BasicBlock.
-  const auto &RestructurePass = getAnalysis<RestructureCFG>();
-  using MarkAnalysis::DuplicationMap;
-  const DuplicationMap &NDuplicates = RestructurePass.getNDuplicates();
-
   // Mark instructions for serialization, and write the results in ToSerialize
   ToSerialize = {};
-  MarkAnalysis::Analysis</* IgnoreDuplicatedUses */ false> Mark(F,
-                                                                NDuplicates,
-                                                                ToSerialize);
+  MarkAnalysis::Analysis Mark(F, ToSerialize);
   Mark.initialize();
   Mark.run();