[llvm] 016022e - Recommit "[LoopFlatten] Move it to a LoopPassManager"

[Sjoerd Meijer via llvm-commits]

Author: Sjoerd Meijer
Date: 2022-01-19T14:38:05Z
New Revision: 016022e5daa821cf22fe3bcfb89878a21fe88937

URL: https://github.com/llvm/llvm-project/commit/016022e5daa821cf22fe3bcfb89878a21fe88937
DIFF: https://github.com/llvm/llvm-project/commit/016022e5daa821cf22fe3bcfb89878a21fe88937.diff

LOG: Recommit "[LoopFlatten] Move it to a LoopPassManager"

This was reverted because of a performance regression, which is fixed by
D116612 that I will commit directly after this change.

This reverts commit e92d63b467e13227408f9726fbd66d07cc58811c.

Added: 
    

Modified: 
    llvm/lib/Passes/PassBuilderPipelines.cpp

Removed: 
    


################################################################################
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.