diff --git a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp index 8540f5ae30c3..4cda6ed4b876 100644 --- a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp +++ b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp @@ -541,7 +541,7 @@ struct LoopInterchange : public FunctionPass { BasicBlock *OuterMostLoopLatch = OuterMostLoop->getLoopLatch(); BranchInst *OuterMostLoopLatchBI = dyn_cast(OuterMostLoopLatch->getTerminator()); - if (!OuterMostLoopLatchBI) + if (!OuterMostLoopLatchBI || OuterMostLoopLatchBI->getNumSuccessors() != 2) return false; // Since we currently do not handle LCSSA PHI's any failure in loop diff --git a/llvm/test/Transforms/LoopInterchange/interchange-latch-no-exit.ll b/llvm/test/Transforms/LoopInterchange/interchange-latch-no-exit.ll new file mode 100644 index 000000000000..b17bbde45e77 --- /dev/null +++ b/llvm/test/Transforms/LoopInterchange/interchange-latch-no-exit.ll @@ -0,0 +1,40 @@ +; RUN: opt < %s -loop-interchange -S | FileCheck %s + +; BB latch1 is the loop latch, but does not exit the loop. +define void @foo() { +entry: + %dest = alloca i16*, align 8 + br label %header1 + +header1: + %0 = phi i16* [ %2, %latch1 ], [ undef, %entry ] + br i1 false, label %inner, label %loopexit + +inner: + br i1 undef, label %inner.ph, label %latch1 + +inner.ph: + br label %inner.body + +inner.body: + %1 = load i16, i16* %0, align 2 + store i16* inttoptr (i64 2 to i16*), i16** %dest, align 8 + br i1 false, label %inner.body, label %inner.loopexit + +inner.loopexit: + br label %latch1 + +latch1: + %2 = phi i16* [ %0, %inner ], [ undef, %inner.loopexit ] + br label %header1 + +loopexit: ; preds = %header1 + unreachable +} + +; CHECK-LABEL: inner.body: +; CHECK: br i1 false, label %inner.body, label %inner.loopexit +; CHECK: latch1: +; CHECK-NEXT: %2 = phi i16* [ %0, %inner ], [ undef, %inner.loopexit ] +; CHECK-NEXT: br label %header1 +