[NewPM] Port ConstraintElimination to the new pass manager

If -enable-constraint-elimination is specified, add it to the -O2/-O3 pipeline.
(-O1 uses a separate function now.)

Reviewed By: fhahn, aeubanks

Differential Revision: https://reviews.llvm.org/D88365

Author: MaskRay

llvm/include/llvm/Transforms/Scalar/ConstraintElimination.h

@@ -0,0 +1,24 @@
+//===- ConstraintElimination.h - Constraint elimination pass ----*- C++ -*-===//
+//
+// 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_CONSTRAINTELIMINATION_H
+#define LLVM_TRANSFORMS_SCALAR_CONSTRAINTELIMINATION_H
+
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+class ConstraintEliminationPass
+    : public PassInfoMixin<ConstraintEliminationPass> {
+public:
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &);
+};
+
+} // end namespace llvm
+
+#endif // LLVM_TRANSFORMS_SCALAR_CONSTRAINTELIMINATION_H

llvm/lib/Passes/PassBuilder.cpp

@@ -130,6 +130,7 @@
 #include "llvm/Transforms/Scalar/BDCE.h"
 #include "llvm/Transforms/Scalar/CallSiteSplitting.h"
 #include "llvm/Transforms/Scalar/ConstantHoisting.h"
+#include "llvm/Transforms/Scalar/ConstraintElimination.h"
 #include "llvm/Transforms/Scalar/CorrelatedValuePropagation.h"
 #include "llvm/Transforms/Scalar/DCE.h"
 #include "llvm/Transforms/Scalar/DeadStoreElimination.h"
@@ -284,6 +285,7 @@ PipelineTuningOptions::PipelineTuningOptions() {
   CallGraphProfile = true;
 }
 
+extern cl::opt<bool> EnableConstraintElimination;
 extern cl::opt<bool> EnableHotColdSplit;
 extern cl::opt<bool> EnableOrderFileInstrumentation;
 
@@ -606,6 +608,9 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
     FPM.addPass(SimplifyCFGPass());
   }
 
+  if (EnableConstraintElimination)
+    FPM.addPass(ConstraintEliminationPass());
+
   // Speculative execution if the target has divergent branches; otherwise nop.
   FPM.addPass(SpeculativeExecutionPass(/* OnlyIfDivergentTarget =*/true));
 

llvm/lib/Passes/PassRegistry.def

@@ -188,6 +188,7 @@ FUNCTION_PASS("bounds-checking", BoundsCheckingPass())
 FUNCTION_PASS("break-crit-edges", BreakCriticalEdgesPass())
 FUNCTION_PASS("callsite-splitting", CallSiteSplittingPass())
 FUNCTION_PASS("consthoist", ConstantHoistingPass())
+FUNCTION_PASS("constraint-elimination", ConstraintEliminationPass())
 FUNCTION_PASS("chr", ControlHeightReductionPass())
 FUNCTION_PASS("coro-early", CoroEarlyPass())
 FUNCTION_PASS("coro-elide", CoroElidePass())

llvm/lib/Transforms/Scalar/ConstraintElimination.cpp

@@ -11,6 +11,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Transforms/Scalar/ConstraintElimination.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/ConstraintSystem.h"
@@ -273,6 +274,19 @@ static bool eliminateConstraints(Function &F, DominatorTree &DT) {
   return Changed;
 }
 
+PreservedAnalyses ConstraintEliminationPass::run(Function &F,
+                                                 FunctionAnalysisManager &AM) {
+  auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
+  if (!eliminateConstraints(F, DT))
+    return PreservedAnalyses::all();
+
+  PreservedAnalyses PA;
+  PA.preserve<DominatorTreeAnalysis>();
+  PA.preserve<GlobalsAA>();
+  PA.preserveSet<CFGAnalyses>();
+  return PA;
+}
+
 namespace {
 
 class ConstraintElimination : public FunctionPass {

llvm/test/Transforms/ConstraintElimination/dom.ll

@@ -1,5 +1,6 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -constraint-elimination -S %s | FileCheck %s
+; RUN: opt -passes=constraint-elimination -S %s | FileCheck %s
 
 ; Test cases where both the true and false successors reach the same block,
 ; dominated by one of them.