[llvm] r195496 - X86: Perform integer comparisons at i32 or larger.

Sean Silva silvas at purdue.edu
Mon Nov 25 22:22:50 PST 2013

On Mon, Nov 25, 2013 at 4:48 PM, Jim Grosbach <grosbach at apple.com> wrote:

> A few select examples I’m seeing are: 256.bzip2 improves by 7%. 401.bzip2
> improves by 4.5%. 300.twolf improves by 3%. 186.crafty improves by 4%. The
> details vary, but this is true for both Ivy Bridge and Haswell in
> particular.
Hmm... on second thought, do these programs use lots of i16's? Agner
reports that on Ivy Bridge and Haswell there is no partial register access
cost for the i8 low subregs. He doesn't seem to mention anything about
16-bit, so I assume that the partial register stall is still there for the
i16 subregs??? I don't have an Ivy Bridge or Haswell to test on
unfortunately :(

-- Sean Silva
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