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| author | Matthew Simpson <mssimpso@codeaurora.org> | 2016-04-11 19:48:18 +0000 |
|---|---|---|
| committer | Matthew Simpson <mssimpso@codeaurora.org> | 2016-04-11 19:48:18 +0000 |
| commit | 53207a99f9d6a93c12bf0114556a7f0dd7e87d1f (patch) | |
| tree | 7ee64cdd7d55a156114c4dc17e8d3f29b9dfcafc /llvm/lib/Transforms/Utils/LoopUtils.cpp | |
| parent | bbf78cda2acd46f614aa263401c3b4f18e1db7c7 (diff) | |
| download | llvm-53207a99f9d6a93c12bf0114556a7f0dd7e87d1f.zip llvm-53207a99f9d6a93c12bf0114556a7f0dd7e87d1f.tar.gz llvm-53207a99f9d6a93c12bf0114556a7f0dd7e87d1f.tar.bz2 | |
[LoopUtils, LV] Fix PR27246 (first-order recurrences)
This patch ensures that when we detect first-order recurrences, we reject a phi
node if its previous value is also a phi node. During vectorization the initial
and previous values of the recurrence are shuffled together to create the value
for the current iteration. However, phi nodes are not widened like other
instructions. This fixes PR27246.
Differential Revision: http://reviews.llvm.org/D18971
llvm-svn: 265983
Diffstat (limited to 'llvm/lib/Transforms/Utils/LoopUtils.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Utils/LoopUtils.cpp | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp index c18887f..a2964c3 100644 --- a/llvm/lib/Transforms/Utils/LoopUtils.cpp +++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp @@ -541,7 +541,7 @@ bool RecurrenceDescriptor::isFirstOrderRecurrence(PHINode *Phi, Loop *TheLoop, // Get the previous value. The previous value comes from the latch edge while // the initial value comes form the preheader edge. auto *Previous = dyn_cast<Instruction>(Phi->getIncomingValueForBlock(Latch)); - if (!Previous || !TheLoop->contains(Previous)) + if (!Previous || !TheLoop->contains(Previous) || isa<PHINode>(Previous)) return false; // Ensure every user of the phi node is dominated by the previous value. The |