[JT] Add an option to dump LazyValueInfo after the run

[davide]

Summary

First step to fix https://bugs.llvm.org/show_bug.cgi?id=33961

[davide]

Sorry, I meant https://bugs.llvm.org/show_bug.cgi?id=33917

[anna]

LGTM. Thanks!

test/Analysis/LazyValueAnalysis/lvi-after-jumpthreading.ll

22

I don't get why these are no longer there - we should either get it from the LVI cache or from the LVI analysis that's run when there's no cache entry.
I'll take a look later.

[davide]

test/Analysis/LazyValueAnalysis/lvi-after-jumpthreading.ll

22

Thank you Anna!

lib/Transforms/Scalar/JumpThreading.cpp

 
 static cl::opt<unsigned>
 ImplicationSearchThreshold(
   "jump-threading-implication-search-threshold",
   cl::desc("The number of predecessors to search for a stronger "
            "condition to use to thread over a weaker condition"),
   cl::init(3), cl::Hidden);
 
+static cl::opt<bool> PrintLVIAfterJumpThreading(
+    "print-lvi-after-jump-threading",
+    cl::desc("Print the LazyValueInfo cache after JumpThreading"), cl::init(false),
+    cl::Hidden);
+
 namespace {
   /// This pass performs 'jump threading', which looks at blocks that have
   /// multiple predecessors and multiple successors.  If one or more of the
   /// predecessors of the block can be proven to always jump to one of the
   /// successors, we forward the edge from the predecessor to the successor by
   /// duplicating the contents of this block.
   ///
   /// An example of when this can occur is code like this:
public:
     static char ID; // Pass identification
     JumpThreading(int T = -1) : FunctionPass(ID), Impl(T) {
       initializeJumpThreadingPass(*PassRegistry::getPassRegistry());
     }
 
     bool runOnFunction(Function &F) override;
 
     void getAnalysisUsage(AnalysisUsage &AU) const override {
+      if (PrintLVIAfterJumpThreading)
+        AU.addRequired<DominatorTreeWrapperPass>();
       AU.addRequired<AAResultsWrapperPass>();
       AU.addRequired<LazyValueInfoWrapperPass>();
       AU.addPreserved<LazyValueInfoWrapperPass>();
       AU.addPreserved<GlobalsAAWrapperPass>();
       AU.addRequired<TargetLibraryInfoWrapperPass>();
     }
 
     void releaseMemory() override { Impl.releaseMemory(); }
bool JumpThreading::runOnFunction(Function &F) {
   std::unique_ptr<BranchProbabilityInfo> BPI;
   bool HasProfileData = F.getEntryCount().hasValue();
   if (HasProfileData) {
     LoopInfo LI{DominatorTree(F)};
     BPI.reset(new BranchProbabilityInfo(F, LI, TLI));
     BFI.reset(new BlockFrequencyInfo(F, *BPI, LI));
   }
 
-  return Impl.runImpl(F, TLI, LVI, AA, HasProfileData, std::move(BFI),
+  bool Changed = Impl.runImpl(F, TLI, LVI, AA, HasProfileData, std::move(BFI),
                               std::move(BPI));
+  if (PrintLVIAfterJumpThreading) {
+    dbgs() << "LVI for function '" << F.getName() << "':\n";
+    LVI->printLVI(F, getAnalysis<DominatorTreeWrapperPass>().getDomTree(),
+                  dbgs());
+  }
+  return Changed;
 }
 
 PreservedAnalyses JumpThreadingPass::run(Function &F,
                                          FunctionAnalysisManager &AM) {
 
   auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
   auto &LVI = AM.getResult<LazyValueAnalysis>(F);
   auto &AA = AM.getResult<AAManager>(F);

test/Analysis/LazyValueAnalysis/lvi-after-jumpthreading.ll

-; RUN: opt < %s -jump-threading -print-lazy-value-info -disable-output 2>&1 | FileCheck %s
+; RUN: opt < %s -jump-threading -print-lvi-after-jump-threading -disable-output 2>&1 | FileCheck %s
 
 ; Testing LVI cache after jump-threading
 
 ; Jump-threading transforms the IR below to one where
 ; loop and backedge basic blocks are merged into one.
 ; basic block (named backedge) with the branch being:
 ; %cont = icmp slt i32 %iv.next, 400
 ; br i1 %cont, label %backedge, label %exit
 define i8 @test1(i32 %a, i32 %length) {
 ; CHECK-LABEL: LVI for function 'test1':
 entry:
 ; CHECK-LABEL: entry:
 ; CHECK-NEXT:    ; LatticeVal for: 'i32 %a' is: overdefined
 ; CHECK-NEXT:    ; LatticeVal for: 'i32 %length' is: overdefined
   br label %loop
 
 ; CHECK-LABEL: backedge:
 ; CHECK-NEXT:     ; LatticeVal for: 'i32 %a' is: overdefined
 ; CHECK-NEXT:     ; LatticeVal for: 'i32 %length' is: overdefined
 ; CHECK-NEXT:     ; LatticeVal for: '  %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]' in BB: '%backedge' is: constantrange<0, 400>
-; CHECK-NEXT:     ; LatticeVal for: '  %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]' in BB: '%exit' is: constantrange<399, 400>
 ; CHECK-NEXT:  %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]
 ; CHECK-NEXT:     ; LatticeVal for: '  %iv.next = add nsw i32 %iv, 1' in BB: '%backedge' is: constantrange<1, 401>
-; CHECK-NEXT:     ; LatticeVal for: '  %iv.next = add nsw i32 %iv, 1' in BB: '%exit' is: constantrange<400, 401>
 ; CHECK-NEXT:  %iv.next = add nsw i32 %iv, 1
 ; CHECK-NEXT:     ; LatticeVal for: '  %cont = icmp slt i32 %iv.next, 400' in BB: '%backedge' is: overdefined
-; CHECK-NEXT:     ; LatticeVal for: '  %cont = icmp slt i32 %iv.next, 400' in BB: '%exit' is: constantrange<0, -1>
 ; CHECK-NEXT:  %cont = icmp slt i32 %iv.next, 400
 ; CHECK-NOT: loop
 loop:
   %iv = phi i32 [0, %entry], [%iv.next, %backedge]
   %cnd = icmp sge i32 %iv, 0
   br i1 %cnd, label %backedge, label %exit
 
 backedge: