[PATCH] D15177: [LoopVectorizer] Refine loop vectorizer's register usage calculator by ignoring specific instructions.

[Cong Hou via llvm-commits]

congh added inline comments.

================
Comment at: lib/Transforms/Vectorize/LoopVectorize.cpp:5645
@@ +5644,3 @@
+    SmallPtrSetImpl<Instruction *> &Casts = RedDes.getCastInsts();
+    ValuesToIgnore.insert(Casts.begin(), Casts.end());
+  }
----------------
hfinkel wrote:
> Shouldn't this be VecValuesToIgnore? These casts are not vectorized, but they are scalar instructions that maintain a live value in a register.
> 
> (Is this the only contributor to ValuesToIgnore?)
OK. This is actually from previous code that I didn't change, which is used in all cases no matter what VF is. Updated.


http://reviews.llvm.org/D15177