Commit fix for generating conditional branch pseudo instructions that
avoids dereferencing the end() iterator when selecting the fallthrough
block. This requires an ilist change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22212 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelPattern.cpp b/lib/Target/PowerPC/PPCISelPattern.cpp
index 5b4c6e5..eaf7b09 100644
--- a/lib/Target/PowerPC/PPCISelPattern.cpp
+++ b/lib/Target/PowerPC/PPCISelPattern.cpp
@@ -1232,9 +1232,9 @@
Select(N.getOperand(0)); //chain
CCReg = SelectCC(N.getOperand(1), Opc, Inv, Idx);
- // Iterate to the next basic block, unless we're already at the end of the
- ilist<MachineBasicBlock>::iterator It = BB, E = BB->getParent()->end();
- if (++It == E) It = BB;
+ // Iterate to the next basic block
+ ilist<MachineBasicBlock>::iterator It = BB;
+ ++It;
// If this is a two way branch, then grab the fallthrough basic block argument
// and build a PowerPC branch pseudo-op, suitable for long branch conversion
@@ -1256,6 +1256,11 @@
}
}
} else {
+ // If the fallthrough path is off the end of the function, which would be
+ // undefined behavior, set it to be the same as the current block because
+ // we have nothing better to set it to, and leaving it alone will cause the
+ // PowerPC Branch Selection pass to crash.
+ if (It == BB->getParent()->end()) It = Dest;
BuildMI(BB, PPC::COND_BRANCH, 4).addReg(CCReg).addImm(Opc)
.addMBB(Dest).addMBB(It);
}