From a80b6c15425f82521c624ff24c5c0a34cd534d54 Mon Sep 17 00:00:00 2001 From: Florian Hahn Date: Wed, 2 Oct 2019 19:38:24 +0000 Subject: [Local] Handle terminators with users in removeUnreachableBlocks. Terminators like invoke can have users outside the current basic block. We have to replace those users with undef, before replacing the terminator. This fixes a crash exposed by rL373430. Reviewers: brzycki, asbirlea, davide, spatel Reviewed By: asbirlea Differential Revision: https://reviews.llvm.org/D68327 llvm-svn: 373513 --- llvm/lib/Transforms/Utils/Local.cpp | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'llvm/lib/Transforms') diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp index 3a6b7a6a655..94339c2ba00 100644 --- a/llvm/lib/Transforms/Utils/Local.cpp +++ b/llvm/lib/Transforms/Utils/Local.cpp @@ -2246,9 +2246,13 @@ bool llvm::removeUnreachableBlocks(Function &F, DomTreeUpdater *DTU, } BB->dropAllReferences(); if (DTU) { - // Remove the terminator of BB to clear the successor list of BB. - if (BB->getTerminator()) - BB->getInstList().pop_back(); + Instruction *TI = BB->getTerminator(); + assert(TI && "Basic block should have a terminator"); + // Terminators like invoke can have users. We have to replace their users, + // before removing them. + if (!TI->use_empty()) + TI->replaceAllUsesWith(UndefValue::get(TI->getType())); + TI->eraseFromParent(); new UnreachableInst(BB->getContext(), BB); assert(succ_empty(BB) && "The successor list of BB isn't empty before " "applying corresponding DTU updates."); -- cgit v1.2.3