[clang] [flang] [llvm] Introduce -fexperimental-loop-fuse to clang and flang (PR #142686)

[Nikita Popov via llvm-commits]

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@@ -65,6 +65,9 @@ class PipelineTuningOptions {
   /// false.
   bool LoopInterchange;
 
+  /// Tuning option to enable/disable loop fusion. Its default value is false.
+  bool LoopFusion;
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nikic wrote:

> This is required at each site which is using PipelineTuningOptions. For LoopInterchange and others, initialization occurs in PassBuilderPipelines.cpp, but for LoopFusion, I can't do this because the definition of the LoopFusion variable is in NewPMDriver.cpp, as suggested by @kasuga-fj.

Why can't you do the initialization to false in PassBuilderPipelines? Isn't this just the default value that later gets overwritten by the code in NewPMDriver?

https://github.com/llvm/llvm-project/pull/142686