[llvm] [MLGO] Model selection for models lowered through EmitC (PR #212650)

[Paul Kirth via llvm-commits]

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@@ -368,14 +405,23 @@ class ReleaseModeEvictionAdvisorProvider final
   getAdvisor(const MachineFunction &MF, const RAGreedy &RA,
              MachineBlockFrequencyInfo *MBFI, MachineLoopInfo *Loops) override {
     if (!Runner) {
-      if (InteractiveChannelBaseName.empty())
-        Runner = std::make_unique<ReleaseModeModelRunner<CompiledModelType>>(
-            MF.getFunction().getContext(), InputFeatures, DecisionName);
-      else
+      if (InteractiveChannelBaseName.empty()) {
+#if defined(LLVM_HAVE_EMITC_COMPILE_REGALLOC)
+        if (SelectedMLGORegAllocModel != MLGORegAllocModelChoice::Default) {
+          Runner = createMLGORegAllocModelRunner(MF.getFunction().getContext(),
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ilovepi wrote:

@beamandala do you think the `constexpr` bits we used in the inliner would make this a bit more natural? This also seems like an almost identical patternl, so perhaps there's a common helper you can use to select the runner?

https://github.com/llvm/llvm-project/pull/212650