[llvm] [llvm-mca][FeatureRequest] Itimeline graph, note source of delay for each instruction (PR #136423)

[Min-Yih Hsu via llvm-commits]

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@@ -255,7 +263,14 @@ void TimelineView::printTimelineViewEntry(formatted_raw_ostream &OS,
 }
 
 static void printTimelineHeader(formatted_raw_ostream &OS, unsigned Cycles) {
-  OS << "\n\nTimeline view:\n";
+  OS << "\n\nTimeline view:\n"
+        "D: Instruction dispatched\n"
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mshockwave wrote:

well, while this syntax is technically correct, I think what Matt suggested was something like
```
OS << "\n\nTimeline view:\n"
   << "D: Instruction dispatched\n"
   ...
```

https://github.com/llvm/llvm-project/pull/136423