[PATCH] Propagate instruction metadata during SLP vectorization.

[hfinkel at anl.gov]

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Comment at: lib/Transforms/Vectorize/SLPVectorizer.cpp:168
@@ +167,3 @@
+static Instruction *propagateMetadata(Instruction *I, ArrayRef<Value *> VL) {
+  Instruction *I0 = dyn_cast<Instruction>(VL[0]);
+  SmallVector<std::pair<unsigned, MDNode*>, 4> Metadata;
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Just make this cast instead of dyn_cast (this way, if there is a problem, we'll get a nice assert here instead of a segfault later).

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Comment at: lib/Transforms/Vectorize/SLPVectorizer.cpp:1517
@@ -1482,1 +1516,3 @@
+
+      return propagateMetadata(dyn_cast<Instruction>(V), E->Scalars);
     }
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Can the cast above fail? Also, don't cast twice (unnecessary overhead; casts are not exactly free).


http://llvm-reviews.chandlerc.com/D2191