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| author | Silviu Baranga <silviu.baranga@arm.com> | 2016-03-21 12:44:29 +0000 |
|---|---|---|
| committer | Silviu Baranga <silviu.baranga@arm.com> | 2016-03-21 12:44:29 +0000 |
| commit | 872392e1a9c2787d731a83a3ec3b998da2855d86 (patch) | |
| tree | accf5ec7836966c1c91dbc103f36b954dea8a54c /lib/Analysis/ScalarEvolutionExpander.cpp | |
| parent | bec2ec108febcc380b0a725ecd87d634b90e648d (diff) | |
[IndVars] Fix PR26974: make sure replaceCongruentIVs doesn't break LCSSA
Summary:
replaceCongruentIVs can break LCSSA when trying to replace IV increments
since it tries to replace all uses of a phi node with another phi node
while both of the phi nodes are not necessarily in the processed loop.
This will cause an assert in IndVars.
To fix this, we add a check to make sure that the replacement maintains
LCSSA.
Reviewers: sanjoy
Subscribers: mzolotukhin, llvm-commits
Differential Revision: http://reviews.llvm.org/D18266
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263941 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis/ScalarEvolutionExpander.cpp')
| -rw-r--r-- | lib/Analysis/ScalarEvolutionExpander.cpp | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp index d083037a90f..4db3c7fb7f9 100644 --- a/lib/Analysis/ScalarEvolutionExpander.cpp +++ b/lib/Analysis/ScalarEvolutionExpander.cpp @@ -1820,6 +1820,7 @@ unsigned SCEVExpander::replaceCongruentIVs(Loop *L, const DominatorTree *DT, IsomorphicInc->getType()); if (OrigInc != IsomorphicInc && TruncExpr == SE.getSCEV(IsomorphicInc) + && SE.LI.replacementPreservesLCSSAForm(IsomorphicInc, OrigInc) && ((isa<PHINode>(OrigInc) && isa<PHINode>(IsomorphicInc)) || hoistIVInc(OrigInc, IsomorphicInc))) { DEBUG_WITH_TYPE(DebugType, dbgs() |