[PATCH] D21720: Unroll for uncountable loops

Evgeny Stupachenko via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Fri Dec 16 12:01:21 PST 2016

evstupac added a comment.

(was unable to answer in phabricator previously, so just put this from mail thread here)

> I realize that it's possible to write such a test. My question was how frequent are such cases in real programs. Can you provide statistics from SPEC/llvm-testsuite that would justify the change?

I'll get the results for llvm test-suite. There is not much difference
on spec2000. There are gains on eembc benhmarks.

> PHIs are present in every loop, in contrast to XORs.

The patch touches only recursive XORs which also go through PHI.
PHIs for optimization after complete unroll are in countable loops. My
patch deals with uncountable (a list loop for example).



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