From 5aad872f8c4d85112172057fb5bf9a7f64013c6c Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Sat, 26 May 2012 21:19:12 +0000 Subject: [PATCH] SDAGBuilder: Don't create an invalid iterator when there is only one switch case. Found by libstdc++'s debug mode. llvm-svn: 157522 --- llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp index 0d37c62..f8cbcaa 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -1984,10 +1984,10 @@ bool SelectionDAGBuilder::handleSmallSwitchRange(CaseRec& CR, } } } - // Rearrange the case blocks so that the last one falls through if possible. Case &BackCase = *(CR.Range.second-1); - if (NextBlock && Default != NextBlock && BackCase.BB != NextBlock) { + if (Size > 1 && + NextBlock && Default != NextBlock && BackCase.BB != NextBlock) { // The last case block won't fall through into 'NextBlock' if we emit the // branches in this order. See if rearranging a case value would help. // We start at the bottom as it's the case with the least weight. -- 2.7.4