Commit Graph

4 Commits

Author SHA1 Message Date
Daniel Berlin 1316a94ebc NewGVN: This patch makes memory congruence work for all types of
memorydefs, not just stores.  Along the way, we audit and fixup issues
about how we were tracking memory leaders, and improve the verifier
to notice more memory congruency issues.

llvm-svn: 299682
2017-04-06 18:52:50 +00:00
Daniel Berlin e3e69e1680 NewGVN: Rewrite DCE during elimination so we do it as well as old GVN did.
llvm-svn: 297428
2017-03-10 00:32:33 +00:00
Daniel Berlin 01831b7db2 NewGVN: Fix PR31613 test regex naming
llvm-svn: 291979
2017-01-13 23:54:10 +00:00
Daniel Berlin c0431fd02d NewGVN: Move leaders around properly to ensure we have a canonical dominating leader. Fixes PR 31613.
Summary:
This is a testcase where phi node cycling happens, and because we do
not order the leaders by domination or anything similar, the leader
keeps changing.

Using std::set for the members is too expensive, and we actually don't
need them sorted all the time, only at leader changes.

We could keep both a set and a vector, and keep them mostly sorted and
resort as necessary, or use a set and a fibheap, but all of this seems
premature.

After running some statistics, we are able to avoid the vast majority
of sorting by keeping a "next leader" field.  Most congruence classes only have
leader changes once or twice during GVN.

Reviewers: davide

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28594

llvm-svn: 291968
2017-01-13 22:40:01 +00:00