[llvm] [SandboxVec][Scheduler] Boilerplate and initial implementation. (PR #112449)

[via llvm-commits]

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@@ -286,7 +290,9 @@ void DependencyGraph::createNewNodes(const Interval<Instruction> &NewInterval) {
         MemDGNodeIntervalBuilder::getBotMemDGNode(TopInterval, *this);
     MemDGNode *LinkBotN =
         MemDGNodeIntervalBuilder::getTopMemDGNode(BotInterval, *this);
-    assert(LinkTopN->comesBefore(LinkBotN) && "Wrong order!");
+    assert((LinkTopN == nullptr || LinkBotN == nullptr ||
+            LinkTopN->comesBefore(LinkBotN)) &&
+           "Wrong order!");
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vporpo wrote:

I think they can be null if there are no no MemDGNodes in the interva.

https://github.com/llvm/llvm-project/pull/112449