diff options
| -rw-r--r-- | llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 16 | ||||
| -rw-r--r-- | llvm/test/Transforms/LoopVectorize/pr32859.ll | 30 |
2 files changed, 39 insertions, 7 deletions
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<PHINode>(&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); + } } } diff --git a/llvm/test/Transforms/LoopVectorize/pr32859.ll b/llvm/test/Transforms/LoopVectorize/pr32859.ll new file mode 100644 index 00000000000..31cb84699f7 --- /dev/null +++ b/llvm/test/Transforms/LoopVectorize/pr32859.ll @@ -0,0 +1,30 @@ +; RUN: opt < %s -loop-vectorize -S | FileCheck %s + +; Out of the LCSSA form we could have 'phi i32 [ loop-invariant, %for.inc.2.i ]' +; but the IR Verifier requires for PHI one entry for each predecessor of +; it's parent basic block. The original PR14725 solution for the issue just +; added 'undef' for an predecessor BB and which is not correct. We copy the real +; value for another predecessor instead of bringing 'undef'. + +; CHECK-LABEL: for.cond.preheader: +; CHECK: %e.0.ph = phi i32 [ 0, %if.end.2.i ], [ 0, %middle.block ] + +; Function Attrs: nounwind uwtable +define void @main() #0 { +entry: + br label %for.cond1.preheader.i + +for.cond1.preheader.i: ; preds = %if.end.2.i, %entry + %c.06.i = phi i32 [ 0, %entry ], [ %inc5.i, %if.end.2.i ] + %tobool.i = icmp ne i32 undef, 0 + br label %if.end.2.i + +if.end.2.i: ; preds = %for.cond1.preheader.i + %inc5.i = add nsw i32 %c.06.i, 1 + %cmp.i = icmp slt i32 %inc5.i, 16 + br i1 %cmp.i, label %for.cond1.preheader.i, label %for.cond.preheader + +for.cond.preheader: ; preds = %if.end.2.i + %e.0.ph = phi i32 [ 0, %if.end.2.i ] + unreachable +} |
