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[IndVars] Preserve LCSSA in `eliminateIdentitySCEV`
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Authored by sanjoy on Oct 6 2015, 1:46 AM.

Details

Summary

After r249211, SCEV can see through some LCSSA phis. Add a
replacementPreservesLCSSAForm check before replacing uses of these phi
nodes with a simplified use of the induction variable to avoid breaking
LCSSA.

Fixes 25047.

Depends on D13460.

Diff Detail

Repository
rL LLVM

Event Timeline

sanjoy updated this revision to Diff 36592.Oct 6 2015, 1:46 AM
sanjoy retitled this revision from to [IndVars] Preserve LCSSA in `eliminateIdentitySCEV`.
sanjoy updated this object.
sanjoy added reviewers: atrick, hfinkel.
sanjoy added a subscriber: llvm-commits.
This revision was automatically updated to reflect the committed changes.

Let's please do a post-commit review on this one -- the change is simple, and people are hitting the bug in tree.