[PATCH] D8943: Calculate vectorization factor using the narrowest type instead of widest type

hfinkel@anl.gov via llvm-commits llvm-commits at lists.llvm.org
Wed Sep 23 12:50:50 PDT 2015

hfinkel added a comment.

Have you run LLVM's test suite with this turned on? Are there any significant performance changes? [I'm happy for this to go in, given that it's disabled by default, even if there are regressions to fix, but I'd like to know where we stand].


Comment at: lib/Transforms/Vectorize/LoopVectorize.cpp:4585
@@ +4584,3 @@
+    // Collect all viable vectorization factors.
+    SmallVector<unsigned, 4> VFs;
+    unsigned NewMaxVectorSize = WidestRegister / SmallestType;
I'd make this 8 instead of 4 (we might have 7 VF for 8-bit integers in AVX-512, for example).


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