[llvm] [MCA] Enable customization of individual instructions (PR #155420)

[Min-Yih Hsu via llvm-commits]

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@@ -134,6 +134,27 @@ class Instrument {
   StringRef getData() const { return Data; }
 };
 
+class LatencyInstrument : public Instrument {
+  std::optional<unsigned> Latency;
+
+public:
+  static const llvm::StringRef DESC_NAME;
+  LatencyInstrument(StringRef Data) : Instrument(DESC_NAME, Data) {
+    // Skip spaces and tabs.
+    unsigned Position = Data.find_first_not_of(" \t");
+    if (Position >= Data.size())
+      // We reached the end of the comment. Bail out.
+      return;
+    Data = Data.drop_front(Position);
+    unsigned L = 0;
+    if (!Data.getAsInteger(10, L))
+      Latency = L;
+  }
+
+  bool hasValue() const { return bool(Latency); }
+  unsigned getLatency() { return *Latency; }
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mshockwave wrote:

I believe this should also be `const`

https://github.com/llvm/llvm-project/pull/155420