Introduce PrecomputeLoopExpressionsPass.

llvm/include/llvm/Transforms/Scalar/PrecomputeLoopExpressions.h

@@ -0,0 +1,27 @@
+//===-------------------- PrecomputeLoopExpressions.h ---------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_SCALAR_PRECOMPUTE_LOOP_EXPRESSIONS_H
+#define LLVM_TRANSFORMS_SCALAR_PRECOMPUTE_LOOP_EXPRESSIONS_H
+
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+class PrecomputeLoopExpressionsPass
+    : public PassInfoMixin<PrecomputeLoopExpressionsPass> {
+  unsigned TotalInitSize;
+
+public:
+  PrecomputeLoopExpressionsPass(unsigned TotalInitSize = 0)
+      : TotalInitSize(TotalInitSize) {}
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
+};
+
+} // end namespace llvm
+
+#endif // LLVM_TRANSFORMS_SCALAR_PRECOMPUTE_LOOP_EXPRESSIONS_H

llvm/lib/Passes/PassBuilderPipelines.cpp

@@ -115,6 +115,7 @@
 #include "llvm/Transforms/Scalar/MemCpyOptimizer.h"
 #include "llvm/Transforms/Scalar/MergedLoadStoreMotion.h"
 #include "llvm/Transforms/Scalar/NewGVN.h"
+#include "llvm/Transforms/Scalar/PrecomputeLoopExpressions.h"
 #include "llvm/Transforms/Scalar/Reassociate.h"
 #include "llvm/Transforms/Scalar/SCCP.h"
 #include "llvm/Transforms/Scalar/SROA.h"
@@ -302,6 +303,8 @@ namespace llvm {
 extern cl::opt<bool> EnableMemProfContextDisambiguation;
 
 extern cl::opt<bool> EnableInferAlignmentPass;
+
+extern cl::opt<bool> DisablePCLE;
 } // namespace llvm
 
 PipelineTuningOptions::PipelineTuningOptions() {
@@ -681,6 +684,10 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
   FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM1),
                                               /*UseMemorySSA=*/true,
                                               /*UseBlockFrequencyInfo=*/true));
+
+  if (!DisablePCLE)
+    FPM.addPass(PrecomputeLoopExpressionsPass());
+
   FPM.addPass(
       SimplifyCFGPass(SimplifyCFGOptions().convertSwitchRangeToICmp(true)));
   FPM.addPass(InstCombinePass());

llvm/lib/Transforms/Scalar/CMakeLists.txt

@@ -61,6 +61,7 @@ add_llvm_component_library(LLVMScalarOpts
   NewGVN.cpp
   PartiallyInlineLibCalls.cpp
   PlaceSafepoints.cpp
+  PrecomputeLoop.cpp
   Reassociate.cpp
   Reg2Mem.cpp
   RewriteStatepointsForGC.cpp