diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/LoopUnswitch.cpp | 8 | ||||
| -rw-r--r-- | llvm/test/Transforms/LoopUnswitch/invalidate-scev.ll | 33 |
2 files changed, 40 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp index b530f7c5dbd..4aae2bfc89c 100644 --- a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp +++ b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp @@ -975,6 +975,10 @@ void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond, Constant *Val, << " blocks] in Function " << L->getHeader()->getParent()->getName() << " on cond: " << *Val << " == " << *Cond << "\n"); + // We are going to make essential changes to CFG. This may invalidate cached + // information for L or one of its parent loops in SCEV. + if (auto *SEWP = getAnalysisIfAvailable<ScalarEvolutionWrapperPass>()) + SEWP->getSE().forgetTopmostLoop(L); // First step, split the preheader, so that we know that there is a safe place // to insert the conditional branch. We will change loopPreheader to have a @@ -1201,8 +1205,10 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val, << " blocks] in Function " << F->getName() << " when '" << *Val << "' == " << *LIC << "\n"); + // We are going to make essential changes to CFG. This may invalidate cached + // information for L or one of its parent loops in SCEV. if (auto *SEWP = getAnalysisIfAvailable<ScalarEvolutionWrapperPass>()) - SEWP->getSE().forgetLoop(L); + SEWP->getSE().forgetTopmostLoop(L); LoopBlocks.clear(); NewBlocks.clear(); diff --git a/llvm/test/Transforms/LoopUnswitch/invalidate-scev.ll b/llvm/test/Transforms/LoopUnswitch/invalidate-scev.ll new file mode 100644 index 00000000000..f1e9443556a --- /dev/null +++ b/llvm/test/Transforms/LoopUnswitch/invalidate-scev.ll @@ -0,0 +1,33 @@ +; RUN: opt -S -indvars -loop-unswitch < %s | FileCheck %s + +target triple = "x86_64-unknown-linux-gnu" + +define void @test_01() { + +; Make sure we don't fail by SCEV's assertion due to incorrect invalidation. +; CHECK-LABEL: @test_01 + +entry: + br label %loop + +loop: ; preds = %backedge, %entry + %p_50.addr.0 = phi i16 [ undef, %entry ], [ %add2699, %backedge ] + %idxprom2690 = sext i16 %p_50.addr.0 to i32 + %arrayidx2691 = getelementptr inbounds [5 x i32], [5 x i32]* undef, i32 0, i32 %idxprom2690 + %0 = load i32, i32* %arrayidx2691, align 1 + %tobool2692 = icmp ne i32 %0, 0 + br label %inner_loop + +inner_loop: ; preds = %inner_backedge, %loop + br i1 %tobool2692, label %backedge, label %inner_backedge + +inner_backedge: ; preds = %inner_loop + br label %inner_loop + +backedge: ; preds = %inner_loop + %add2699 = add nsw i16 %p_50.addr.0, 1 + br i1 false, label %loop, label %exit + +exit: ; preds = %backedge + unreachable +} |
