Fix integer overflow in instruction scheduling. This can happen if we have
basic blocks that are so long that their size overflows a short.
Also assert that overflow does not happen in the future, as requested by Evan.
This fixes PR4401.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83159 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/ScheduleDAG.cpp b/lib/CodeGen/ScheduleDAG.cpp
index ff5c236..5a59862 100644
--- a/lib/CodeGen/ScheduleDAG.cpp
+++ b/lib/CodeGen/ScheduleDAG.cpp
@@ -82,13 +82,19 @@
SUnit *N = D.getSUnit();
// Update the bookkeeping.
if (D.getKind() == SDep::Data) {
+ assert(NumPreds < UINT_MAX && "NumPreds will overflow!");
+ assert(N->NumSuccs < UINT_MAX && "NumSuccs will overflow!");
++NumPreds;
++N->NumSuccs;
}
- if (!N->isScheduled)
+ if (!N->isScheduled) {
+ assert(NumPredsLeft < UINT_MAX && "NumPredsLeft will overflow!");
++NumPredsLeft;
- if (!isScheduled)
+ }
+ if (!isScheduled) {
+ assert(N->NumSuccsLeft < UINT_MAX && "NumSuccsLeft will overflow!");
++N->NumSuccsLeft;
+ }
Preds.push_back(D);
N->Succs.push_back(P);
if (P.getLatency() != 0) {
@@ -121,13 +127,19 @@
Preds.erase(I);
// Update the bookkeeping.
if (P.getKind() == SDep::Data) {
+ assert(NumPreds > 0 && "NumPreds will underflow!");
+ assert(N->NumSuccs > 0 && "NumSuccs will underflow!");
--NumPreds;
--N->NumSuccs;
}
- if (!N->isScheduled)
+ if (!N->isScheduled) {
+ assert(NumPredsLeft > 0 && "NumPredsLeft will underflow!");
--NumPredsLeft;
- if (!isScheduled)
+ }
+ if (!isScheduled) {
+ assert(N->NumSuccsLeft > 0 && "NumSuccsLeft will underflow!");
--N->NumSuccsLeft;
+ }
if (P.getLatency() != 0) {
this->setDepthDirty();
N->setHeightDirty();