[llvm] 86825fc - [LoopFlatten] Move it to a LoopPassManager

[Sjoerd Meijer via llvm-commits]

Author: Sjoerd Meijer
Date: 2021-12-30T12:32:14Z
New Revision: 86825fc2fb363b807569327880c05e4b0b5393ec

URL: https://github.com/llvm/llvm-project/commit/86825fc2fb363b807569327880c05e4b0b5393ec
DIFF: https://github.com/llvm/llvm-project/commit/86825fc2fb363b807569327880c05e4b0b5393ec.diff

LOG: [LoopFlatten] Move it to a LoopPassManager

In D109958 it was noticed that we could optimise the pipeline and avoid
rerunning LoopSimplify/LCSSA for LoopFlatten by moving it to a LoopPassManager.

Differential Revision: https://reviews.llvm.org/D110057

Added: 
    

Modified: 
    llvm/lib/Passes/PassBuilderPipelines.cpp

Removed: 
    


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diff  --git a/llvm/lib/Passes/PassBuilderPipelines.cpp b/llvm/lib/Passes/PassBuilderPipelines.cpp
index a6a36ff254029..79c42b886fbbe 100644
--- a/llvm/lib/Passes/PassBuilderPipelines.cpp
+++ b/llvm/lib/Passes/PassBuilderPipelines.cpp
@@ -311,6 +311,8 @@ PassBuilder::buildO1FunctionSimplificationPipeline(OptimizationLevel Level,
 
   if (EnableLoopInterchange)
     LPM2.addPass(LoopInterchangePass());
+  if (EnableLoopFlatten)
+    LPM2.addPass(LoopFlattenPass());
 
   // Do not enable unrolling in PreLinkThinLTO phase during sample PGO
   // because it changes IR to makes profile annotation in back compile
@@ -335,8 +337,6 @@ PassBuilder::buildO1FunctionSimplificationPipeline(OptimizationLevel Level,
                                               /*UseBlockFrequencyInfo=*/true));
   FPM.addPass(SimplifyCFGPass());
   FPM.addPass(InstCombinePass());
-  if (EnableLoopFlatten)
-    FPM.addPass(createFunctionToLoopPassAdaptor(LoopFlattenPass()));
   // The loop passes in LPM2 (LoopFullUnrollPass) do not preserve MemorySSA.
   // *All* loop passes must preserve it, in order to be able to use it.
   FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM2),
@@ -485,6 +485,8 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
 
   if (EnableLoopInterchange)
     LPM2.addPass(LoopInterchangePass());
+  if (EnableLoopFlatten)
+    LPM2.addPass(LoopFlattenPass());
 
   // Do not enable unrolling in PreLinkThinLTO phase during sample PGO
   // because it changes IR to makes profile annotation in back compile
@@ -509,8 +511,6 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
                                               /*UseBlockFrequencyInfo=*/true));
   FPM.addPass(SimplifyCFGPass());
   FPM.addPass(InstCombinePass());
-  if (EnableLoopFlatten)
-    FPM.addPass(createFunctionToLoopPassAdaptor(LoopFlattenPass()));
   // The loop passes in LPM2 (LoopIdiomRecognizePass, IndVarSimplifyPass,
   // LoopDeletionPass and LoopFullUnrollPass) do not preserve MemorySSA.
   // *All* loop passes must preserve it, in order to be able to use it.
@@ -1623,9 +1623,6 @@ PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
   MainFPM.addPass(DSEPass());
   MainFPM.addPass(MergedLoadStoreMotionPass());
 
-  // More loops are countable; try to optimize them.
-  if (EnableLoopFlatten && Level.getSpeedupLevel() > 1)
-    MainFPM.addPass(createFunctionToLoopPassAdaptor(LoopFlattenPass()));
 
   if (EnableConstraintElimination)
     MainFPM.addPass(ConstraintEliminationPass());
@@ -1633,6 +1630,8 @@ PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
   LoopPassManager LPM;
   LPM.addPass(IndVarSimplifyPass());
   LPM.addPass(LoopDeletionPass());
+  if (EnableLoopFlatten && Level.getSpeedupLevel() > 1)
+    LPM.addPass(LoopFlattenPass());
   // FIXME: Add loop interchange.
 
   // Unroll small loops and perform peeling.