tree 36225d71cf73da4529403160aaa45147d1dfc556
parent 47e88504c98094dcd2139eb818ba55cbf70811a0
author Florian Hahn <flo@fhahn.com> 1596047714 +0100
committer Copybara-Service <copybara-worker@google.com> 1599181908 -0700

Reland "[SCEVExpander] Add option to preserve LCSSA directly."

This reverts the revert commit dc2867576886247cbe351e7c63618c09ab6af808.

It includes a fix for Polly, which uses SCEVExpander on IR that is not
in LCSSA form. Set PreserveLCSSA = false in that case, to ensure we do
not introduce LCSSA phis where there were none before.

GitOrigin-RevId: f75564ad4e4799465cf14b96f761e3fae13f6976