From ddeabf78a0b04579dc03f3d3ff862fc05943db6c Mon Sep 17 00:00:00 2001 From: Cameron Zwarich Date: Sun, 17 Feb 2013 01:45:04 +0000 Subject: [PATCH] Fix a conversion from a forward iterator to a reverse iterator in MachineBasicBlock::SplitCriticalEdge. Since this is an iterator rather than an instr_iterator, the isBundled() check only passes if getFirstTerminator() returned end() and the garbage memory happens to lean that way. Multiple successors can be present without any terminator instructions in the case of exception handling with a fallthrough. llvm-svn: 175383 --- llvm/lib/CodeGen/MachineBasicBlock.cpp | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/llvm/lib/CodeGen/MachineBasicBlock.cpp b/llvm/lib/CodeGen/MachineBasicBlock.cpp index 3d75436..f22a707 100644 --- a/llvm/lib/CodeGen/MachineBasicBlock.cpp +++ b/llvm/lib/CodeGen/MachineBasicBlock.cpp @@ -852,12 +852,13 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { // Update all intervals for registers whose uses may have been modified by // updateTerminator(). iterator FirstTerminator = getFirstTerminator(); - MachineInstr *FirstTerminatorMI = FirstTerminator; - if (FirstTerminatorMI->isBundled()) - FirstTerminatorMI = getBundleStart(FirstTerminatorMI); - reverse_iterator PreTerminators = - (FirstTerminator == begin()) ? rend() - : reverse_iterator(FirstTerminatorMI); + reverse_iterator PreTerminators; + if (FirstTerminator == begin()) + PreTerminators = rend(); + else if (FirstTerminator == end()) + PreTerminators = rbegin(); + else + PreTerminators = reverse_iterator(FirstTerminator); LIS->repairIntervalsInRange(this, rbegin(), PreTerminators, UsedRegs); } -- 2.7.4