[flang-commits] [mlir] [flang] [Flang][Lower] Attach target_cpu and target_features attributes to MLIR functions (PR #78289)

[Sergio Afonso via flang-commits]

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@@ -4290,6 +4291,18 @@ class FirConverter : public Fortran::lower::AbstractConverter {
     assert(blockId == 0 && "invalid blockId");
     assert(activeConstructStack.empty() && "invalid construct stack state");
 
+    // Set target_cpu and target_features attributes to be passed through to the
+    // llvm.func operation during lowering.
+    const llvm::TargetMachine &targetMachine = bridge.getTargetMachine();
+    if (auto targetCPU = targetMachine.getTargetCPU(); !targetCPU.empty())
+      func->setAttr("target_cpu",
+                    mlir::StringAttr::get(func.getContext(), targetCPU));
+
+    if (auto targetFeatures = targetMachine.getTargetFeatureString();
+        !targetFeatures.empty())
+      func->setAttr("target_features", mlir::LLVM::TargetFeaturesAttr::get(
+                                           func.getContext(), targetFeatures));
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skatrak wrote:

Thank you all for sharing your suggestions and concerns, I can now understand better the problems with this approach so I'll work on following @jeanPerier's suggested alternative and move this logic from the lowering bridge to the target rewrite pass. This should also address the annotation of function declarations raised by @Leporacanthicus, which I tested to not be covered by this patch in its current form.

https://github.com/llvm/llvm-project/pull/78289