[PM] Port BreakCriticalEdges to the new PM

[davide]

The structure is OK (modulo nit), but I have a comment about the tests.

lib/Transforms/Utils/BreakCriticalEdges.cpp

49

This line is unchanged, right? If yes, you can remove that to improve the commit readability.

test/Analysis/Dominators/2006-10-02-BreakCritEdges.ll

2

Here you have -domtree -break-critical-egdes -domtree which in the new PM becomes require<domtree>,break-crit-edges,print<domtree>.
In the next test you have (almost) the same line which instead becomes
require<domtree>,break-crit-edges,require<domtree>.
What is the reason of this difference? (maybe I'm missing the obvious here).

[wmi]

lib/Transforms/Utils/BreakCriticalEdges.cpp

49

Ok.

test/Analysis/Dominators/2006-10-02-BreakCritEdges.ll

2

I could be wrong. Here I guess print<domtree> will imply domtree analysis? I used test/Analysis/Dominators/basic.ll as a reference:

; RUN: opt < %s -domtree -analyze | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-OLDPM
; RUN: opt < %s -disable-output -passes='print<domtree>' 2>&1 | FileCheck %s -check-prefix=CHECK -check-prefix=CHECK-NEWPM

basic.ll uses print<domtree> so it doesn't have to specify require<domtree> again?

[davide]

LGTM. David?

[davidxl]

lgtm

include/llvm/Transforms/Utils/BreakCriticalEdges.h

+//===- BreakCriticalEdges.h - Critical Edge Elimination Pass --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// BreakCriticalEdges pass - Break all of the critical edges in the CFG by
+// inserting a dummy basic block.  This pass may be "required" by passes that
+// cannot deal with critical edges.  For this usage, the structure type is
+// forward declared.  This pass obviously invalidates the CFG, but can update
+// dominator trees.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_UTILS_BREAKCRITICALEDGES_H
+#define LLVM_TRANSFORMS_UTILS_BREAKCRITICALEDGES_H
+
+#include "llvm/IR/Function.h"
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+struct BreakCriticalEdgesPass : public PassInfoMixin<BreakCriticalEdgesPass> {
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
+};
+} // namespace llvm
+#endif // LLVM_TRANSFORMS_UTILS_BREAKCRITICALEDGES_H

lib/Passes/PassBuilder.cpp

 #include "llvm/Transforms/Scalar/PartiallyInlineLibCalls.h"
 #include "llvm/Transforms/Scalar/Reassociate.h"
 #include "llvm/Transforms/Scalar/SCCP.h"
 #include "llvm/Transforms/Scalar/SROA.h"
 #include "llvm/Transforms/Scalar/SimplifyCFG.h"
 #include "llvm/Transforms/Scalar/Sink.h"
 #include "llvm/Transforms/Scalar/TailRecursionElimination.h"
 #include "llvm/Transforms/Utils/AddDiscriminators.h"
+#include "llvm/Transforms/Utils/BreakCriticalEdges.h"
 #include "llvm/Transforms/Utils/LCSSA.h"
 #include "llvm/Transforms/Utils/LoopSimplify.h"
 #include "llvm/Transforms/Utils/Mem2Reg.h"
 #include "llvm/Transforms/Utils/MemorySSA.h"
 #include "llvm/Transforms/Utils/SimplifyInstructions.h"
 #include "llvm/Transforms/Vectorize/LoopVectorize.h"
 #include "llvm/Transforms/Vectorize/SLPVectorizer.h"
 

lib/Passes/PassRegistry.def

 #ifndef FUNCTION_PASS
 #define FUNCTION_PASS(NAME, CREATE_PASS)
 #endif
 FUNCTION_PASS("aa-eval", AAEvaluator())
 FUNCTION_PASS("adce", ADCEPass())
 FUNCTION_PASS("add-discriminators", AddDiscriminatorsPass())
 FUNCTION_PASS("alignment-from-assumptions", AlignmentFromAssumptionsPass())
 FUNCTION_PASS("bdce", BDCEPass())
+FUNCTION_PASS("break-crit-edges", BreakCriticalEdgesPass())
 FUNCTION_PASS("consthoist", ConstantHoistingPass())
 FUNCTION_PASS("correlated-propagation", CorrelatedValuePropagationPass())
 FUNCTION_PASS("dce", DCEPass())
 FUNCTION_PASS("dse", DSEPass())
 FUNCTION_PASS("early-cse", EarlyCSEPass())
 FUNCTION_PASS("gvn-hoist", GVNHoistPass())
 FUNCTION_PASS("instcombine", InstCombinePass())
 FUNCTION_PASS("instsimplify", InstSimplifierPass())

lib/Transforms/Utils/BreakCriticalEdges.cpp

 // BreakCriticalEdges pass - Break all of the critical edges in the CFG by
 // inserting a dummy basic block.  This pass may be "required" by passes that
 // cannot deal with critical edges.  For this usage, the structure type is
 // forward declared.  This pass obviously invalidates the CFG, but can update
 // dominator trees.
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/BreakCriticalEdges.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/CFG.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/Dominators.h"
-#include "llvm/IR/Function.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/Type.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Transforms/Scalar.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "break-crit-edges"
 
 STATISTIC(NumBroken, "Number of blocks inserted");
 
 namespace {
-  struct BreakCriticalEdges : public FunctionPass {
-    static char ID; // Pass identification, replacement for typeid
-    BreakCriticalEdges() : FunctionPass(ID) {
-      initializeBreakCriticalEdgesPass(*PassRegistry::getPassRegistry());
-    }
 
-    bool runOnFunction(Function &F) override {
-      auto *DTWP = getAnalysisIfAvailable<DominatorTreeWrapperPass>();
-      auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
-      auto *LIWP = getAnalysisIfAvailable<LoopInfoWrapperPass>();
-      auto *LI = LIWP ? &LIWP->getLoopInfo() : nullptr;
-      unsigned N =
-          SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions(DT, LI));
-      NumBroken += N;
-      return N > 0;
-    }
+    unsigned N = SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions(DT, LI));
 
-    void getAnalysisUsage(AnalysisUsage &AU) const override {
-      AU.addPreserved<DominatorTreeWrapperPass>();
-      AU.addPreserved<LoopInfoWrapperPass>();
 
-      // No loop canonicalization guarantees are broken by this pass.
-      AU.addPreservedID(LoopSimplifyID);
-    }
-  };
 }
 
 char BreakCriticalEdges::ID = 0;
 INITIALIZE_PASS(BreakCriticalEdges, "break-crit-edges",
                 "Break critical edges in CFG", false, false)
 
 // Publicly exposed interface to pass...
 char &llvm::BreakCriticalEdgesID = BreakCriticalEdges::ID;
 FunctionPass *llvm::createBreakCriticalEdgesPass() {
   return new BreakCriticalEdges();
 }
 
+PreservedAnalyses BreakCriticalEdgesPass::run(Function &F,
+                                              FunctionAnalysisManager &AM) {
+  auto *DT = AM.getCachedResult<DominatorTreeAnalysis>(F);
+  auto *LI = AM.getCachedResult<LoopAnalysis>(F);
+  unsigned N = SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions(DT, LI));
+  NumBroken += N;
+  if (N == 0)
+    return PreservedAnalyses::all();
+  PreservedAnalyses PA;
+  PA.preserve<DominatorTreeAnalysis>();
+  PA.preserve<LoopAnalysis>();
+  return PA;
+}
+
 //===----------------------------------------------------------------------===//
 //    Implementation of the external critical edge manipulation functions
 //===----------------------------------------------------------------------===//
 
 /// When a loop exit edge is split, LCSSA form may require new PHIs in the new
 /// exit block. This function inserts the new PHIs, as needed. Preds is a list
 /// of preds inside the loop, SplitBB is the new loop exit block, and DestBB is
 /// the old loop exit, now the successor of SplitBB.

test/Analysis/Dominators/2006-10-02-BreakCritEdges.ll

 ; RUN: opt < %s -domtree -break-crit-edges -analyze -domtree | FileCheck %s
+; RUN: opt < %s -passes='require<domtree>,break-crit-edges,print<domtree>' -disable-output 2>&1| FileCheck %s
 ; PR932
 
 ; CHECK: [3] %brtrue {1,2}
 
 declare void @use1(i32)
 
 define void @f(i32 %i, i1 %c) {
 entry:

test/Analysis/Dominators/2007-01-14-BreakCritEdges.ll

 ; RUN: opt < %s -domtree -break-crit-edges -domtree -disable-output
+; RUN: opt < %s -passes='require<domtree>,break-crit-edges,require<domtree>' -disable-output
 ; PR1110
 
   %struct.OggVorbis_File = type { i8*, i32, i64, i64, %struct.ogg_sync_state, i32, i64*, i64*, i32*, i64*, %struct.vorbis_info*, %struct.vorbis_comment*, i64, i32, i32, i32, double, double, %struct.ogg_stream_state, %struct.vorbis_dsp_state, %struct.vorbis_block, %struct.ov_callbacks }
   %struct.alloc_chain = type { i8*, %struct.alloc_chain* }
   %struct.ogg_stream_state = type { i8*, i32, i32, i32, i32*, i64*, i32, i32, i32, i32, [282 x i8], i32, i32, i32, i32, i32, i64, i64 }
   %struct.ogg_sync_state = type { i8*, i32, i32, i32, i32, i32, i32 }
   %struct.oggpack_buffer = type { i32, i32, i8*, i8*, i32 }
   %struct.ov_callbacks = type { i32 (i8*, i32, i32, i8*)*, i32 (i8*, i64, i32)*, i32 (i8*)*, i32 (i8*)* }