From 7d62e4b455cf181d1657cf8e3be18fd5c0d2eb27 Mon Sep 17 00:00:00 2001 From: Simon Pilgrim Date: Sat, 13 May 2017 13:25:57 +0000 Subject: [LoopOptimizer][Fix]PR32859, PR24738 The Loop vectorizer pass introduced undef value while it is fixing output of LCSSA form. Here it is: before: %e.0.ph = phi i32 [ 0, %for.inc.2.i ] after: %e.0.ph = phi i32 [ 0, %for.inc.2.i ], [ undef, %middle.block ] and after this change we have: %e.0.ph = phi i32 [ 0, %for.inc.2.i ] %e.0.ph = phi i32 [ 0, %for.inc.2.i ], [ 0, %middle.block ] Committed on behalf of @dtemirbulatov Differential Revision: https://reviews.llvm.org/D33055 llvm-svn: 302988 --- llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) (limited to 'llvm/lib/Transforms') diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp index 45a86dbb785..516ab7d03a8 100644 --- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp +++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -446,10 +446,10 @@ protected: /// vectorizing this phi node. void fixReduction(PHINode *Phi); - /// \brief The Loop exit block may have single value PHI nodes where the - /// incoming value is 'Undef'. While vectorizing we only handled real values - /// that were defined inside the loop. Here we fix the 'undef case'. - /// See PR14725. + /// \brief The Loop exit block may have single value PHI nodes with some + /// incoming value. While vectorizing we only handled real values + /// that were defined inside the loop and we should have one value for + /// each predecessor of its parent basic block. See PR14725. void fixLCSSAPHIs(); /// Iteratively sink the scalarized operands of a predicated instruction into @@ -4300,9 +4300,11 @@ void InnerLoopVectorizer::fixLCSSAPHIs() { auto *LCSSAPhi = dyn_cast(&LEI); if (!LCSSAPhi) break; - if (LCSSAPhi->getNumIncomingValues() == 1) - LCSSAPhi->addIncoming(UndefValue::get(LCSSAPhi->getType()), - LoopMiddleBlock); + if (LCSSAPhi->getNumIncomingValues() == 1) { + assert(OrigLoop->isLoopInvariant(LCSSAPhi->getIncomingValue(0)) && + "Incoming value isn't loop invariant"); + LCSSAPhi->addIncoming(LCSSAPhi->getIncomingValue(0), LoopMiddleBlock); + } } } -- cgit v1.2.3