[PATCH] D113291: [AggressiveInstCombine] Lower Table Based CTTZ

[Dave Green via Phabricator via llvm-commits]

dmgreen accepted this revision.
dmgreen added a comment.

Thanks for the updates. LGTM



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Comment at: llvm/lib/Transforms/AggressiveInstCombine/AggressiveInstCombine.cpp:604
+
+  // Shift should extract top 5..7 bits.
+  if (InputBits - Log2_32(InputBits) != ShiftConst &&
----------------
craig.topper wrote:
> If we’re only handling 32 and 64, this comment should be 5..6
I believe it is 7 because the table can be twice the size. Hence the -1 in the formula below. See the ctz2 test.


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