[flang-commits] [flang] 81f5098 - [flang] Enable optimizeEmptyElementals for BufferizeHLFIR pass. (#124982)

[via flang-commits]

Author: Slava Zakharin
Date: 2025-01-30T07:45:51-08:00
New Revision: 81f50989016a16f2d9e93cd220a89f1af851dfda

URL: https://github.com/llvm/llvm-project/commit/81f50989016a16f2d9e93cd220a89f1af851dfda
DIFF: https://github.com/llvm/llvm-project/commit/81f50989016a16f2d9e93cd220a89f1af851dfda.diff

LOG: [flang] Enable optimizeEmptyElementals for BufferizeHLFIR pass. (#124982)

Enable the option under opt-for-speed. Elementals with shapes
like `(0, HUGE)` should run faster.

Added: 
    

Modified: 
    flang/lib/Optimizer/Passes/Pipelines.cpp

Removed: 
    


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diff  --git a/flang/lib/Optimizer/Passes/Pipelines.cpp b/flang/lib/Optimizer/Passes/Pipelines.cpp
index 1cc3f0b81c20ad..d55ad9e603ffaf 100644
--- a/flang/lib/Optimizer/Passes/Pipelines.cpp
+++ b/flang/lib/Optimizer/Passes/Pipelines.cpp
@@ -245,7 +245,15 @@ void createHLFIRToFIRPassPipeline(mlir::PassManager &pm, bool enableOpenMP,
   }
   pm.addPass(hlfir::createLowerHLFIROrderedAssignments());
   pm.addPass(hlfir::createLowerHLFIRIntrinsics());
-  pm.addPass(hlfir::createBufferizeHLFIR());
+
+  hlfir::BufferizeHLFIROptions bufferizeOptions;
+  // For opt-for-speed, avoid running any of the loops resulting
+  // from hlfir.elemental lowering, if the result is an empty array.
+  // This helps to avoid long running loops for elementals with
+  // shapes like (0, HUGE).
+  if (optLevel.isOptimizingForSpeed())
+    bufferizeOptions.optimizeEmptyElementals = true;
+  pm.addPass(hlfir::createBufferizeHLFIR(bufferizeOptions));
   // Run hlfir.assign inlining again after BufferizeHLFIR,
   // because the latter may introduce new hlfir.assign operations,
   // e.g. for copying an array into a temporary due to