From 53207a99f9d6a93c12bf0114556a7f0dd7e87d1f Mon Sep 17 00:00:00 2001 From: Matthew Simpson Date: Mon, 11 Apr 2016 19:48:18 +0000 Subject: [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 --- llvm/lib/Transforms/Utils/LoopUtils.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'llvm/lib/Transforms/Utils/LoopUtils.cpp') diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp index c18887f697e..a2964c38a87 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(Phi->getIncomingValueForBlock(Latch)); - if (!Previous || !TheLoop->contains(Previous)) + if (!Previous || !TheLoop->contains(Previous) || isa(Previous)) return false; // Ensure every user of the phi node is dominated by the previous value. The -- cgit v1.2.3