[PATCH] D71238: Align non-fused branches within 32-Byte boundary (basic case)

annita.zhang via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Mon Dec 16 00:51:09 PST 2019


annita.zhang added a comment.

In D71238#1776751 <https://reviews.llvm.org/D71238#1776751>, @chandlerc wrote:

> I just want to mention here, that my comment on the original patch still stands and really needs to be addressed:
>
> We need to have detailed performance and binary size numbers for this kind of change. We should be looking at the test suite and SPEC for performance. I'd like to see before/after performance numbers on a system that is *not* using the microcode feature that addresses jCC (either a newer CPU, an older CPu, or an unpatched CPU). I'd also like to see before/after performance numbers on a system that *is* using the microcode feature to address the jCC issue. I'd suggest Clang itself, Firefox, and Chromium as binaries to show the binary size impact of this patch. Happy for others to suggest binaries to use to evaluate the binary size impact.
>
> I continue to think that any patch we plan to land should have these numbers, and each incremental update to that patch should have the updated numbers. Otherwise, there is no way to do a good job reviewing the *impact* of these changes even after folks are satisfied with the *code* in these changes.


More performance data was posted on http://lists.llvm.org/pipermail/llvm-dev/2019-December/137609.html and http://lists.llvm.org/pipermail/llvm-dev/2019-December/137610.html. Let's move on based on the performance data.


Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71238/new/

https://reviews.llvm.org/D71238





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