From 67f74aceab191c5ecad2394edb267ecee49d872d Mon Sep 17 00:00:00 2001 From: Heejin Ahn Date: Fri, 29 Mar 2019 19:36:51 +0000 Subject: [WebAssembly] Handle END_LOOP in unreachable BB in CFGStackify Summary: This fixes crashes when a BB in which an END_LOOP is to be placed is unreachable and does not have any predecessors. Fixes PR41307. Reviewers: dschuff Subscribers: yurydelendik, sbc100, jgravelle-google, sunfish, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D60004 llvm-svn: 357303 --- llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp') diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp index 39641b414cb..b64aa3023bb 100644 --- a/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp +++ b/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp @@ -411,7 +411,9 @@ void WebAssemblyCFGStackify::placeLoopMarker(MachineBasicBlock &MBB) { // Mark the end of the loop (using arbitrary debug location that branched to // the loop end as its location). InsertPos = getEarliestInsertPos(AfterLoop, BeforeSet, AfterSet); - DebugLoc EndDL = (*AfterLoop->pred_rbegin())->findBranchDebugLoc(); + DebugLoc EndDL = AfterLoop->pred_empty() + ? DebugLoc() + : (*AfterLoop->pred_rbegin())->findBranchDebugLoc(); MachineInstr *End = BuildMI(*AfterLoop, InsertPos, EndDL, TII.get(WebAssembly::END_LOOP)); registerScope(Begin, End); -- cgit v1.2.3