[PATCH] D71180: [NFC][MacroFusion] Adding the assertion if someone want to fuse more than 2 instructions.

[qshanz via Phabricator via llvm-commits]

steven.zhang updated this revision to Diff 232756.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71180/new/

https://reviews.llvm.org/D71180

Files:
  llvm/lib/CodeGen/MacroFusion.cpp


Index: llvm/lib/CodeGen/MacroFusion.cpp
===================================================================
--- llvm/lib/CodeGen/MacroFusion.cpp
+++ llvm/lib/CodeGen/MacroFusion.cpp
@@ -71,6 +71,14 @@
   if (!DAG.addEdge(&SecondSU, SDep(&FirstSU, SDep::Cluster)))
     return false;
 
+  // TODO - If we want to chain more than two instructions, we need to create
+  // artifical edges to make dependencies from the FirstSU also dependent
+  // on other chained instructions, and other chained instructions also
+  // dependent on the dependencies of the SecondSU, to prevent them from being
+  // scheduled into these chained instructions.
+  assert(hasLessThanNumFused(FirstSU, 2) &&
+         "Chain two instructions together at most");
+
   // Adjust the latency between both instrs.
   for (SDep &SI : FirstSU.Succs)
     if (SI.getSUnit() == &SecondSU)


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