[PATCH] D23906: LSV: Fix incorrectly increasing alignment

Eli Friedman via llvm-commits llvm-commits at lists.llvm.org
Wed Aug 31 09:54:29 PDT 2016

efriedma added inline comments.

Comment at: lib/Transforms/Vectorize/LoadStoreVectorizer.cpp:799
@@ +798,3 @@
+                                                   StackAdjustedAlignment,
+                                                   DL, S0, nullptr, &DT);
+    if (NewAlign <= Alignment)
arsenm wrote:
> efriedma wrote:
> > I'm sort of confused about what you're doing here... what is StackAdjustedAlignment supposed to be?
> It's supposed to be a normal "good" stack alignment value that will generally allow vectorization. It's a hardcoded 4 because the GPUs we care about this always works. This should be something smarter, but that's a separate change
Okay... but if StackAdjustedAlignment is the alignment which allows vectorization, shouldn't you be checking "NewAlign <= StackAdjustedAlignment", as opposed to "NewAlign <= Alignment"?


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