[LoopAccesses 3/3] Print the dependences with -analyze

[anemet]

Summary

The dependences are now expose through the new getInterestingDependences
API so we can use that with -analyze too and fix the FIXME.

This lets us remove the test that relied on -debug to check the
dependences.

[hfinkel]

LGTM.

[anemet]

r231807

include/llvm/Analysis/LoopAccessAnalysis.h

enum DepType {
       Backward,
       // Backward but the distance allows vectorization factor of
       // MaxSafeDepDistBytes.
       BackwardVectorizable,
       // Same but may prevent store-to-load forwarding.
       BackwardVectorizableButPreventsForwarding
     };
 
+    /// \brief String version of the types.
+    static const char *DepName[];
+
     /// \brief Index of the source of the dependence in the InstMap vector.
     unsigned Source;
     /// \brief Index of the destination of the dependence in the InstMap vector.
     unsigned Destination;
     /// \brief The type of the dependence.
     DepType Type;
 
     Dependence(unsigned Source, unsigned Destination, DepType Type)
         : Source(Source), Destination(Destination), Type(Type) {}
 
     /// \brief Dependence types that don't prevent vectorization.
     static bool isSafeForVectorization(DepType Type);
 
     /// \brief Dependence types that can be queried from the analysis.
     static bool isInterestingDependence(DepType Type);
 
     /// \brief Lexically backward dependence types.
     bool isPossiblyBackward() const;
+
+    /// \brief Print the dependence.  \p Instr is used to map the instruction
+    /// indices to instructions.
+    void print(raw_ostream &OS, unsigned Depth,
+               const SmallVectorImpl<Instruction *> &Instrs) const;
   };
 
   MemoryDepChecker(ScalarEvolution *Se, const DataLayout *Dl, const Loop *L)
       : SE(Se), DL(Dl), InnermostLoop(L), AccessIdx(0),
         ShouldRetryWithRuntimeCheck(false), SafeForVectorization(true),
         RecordInterestingDependences(true) {}
 
   /// \brief Register the location (instructions are given increasing numbers)

lib/Analysis/LoopAccessAnalysis.cpp

while (!CheckDeps.empty()) {
     }
   }
 
   DEBUG(dbgs() << "Total Interesting Dependences: "
                << InterestingDependences.size() << "\n");
   return SafeForVectorization;
 }
 
+const char *MemoryDepChecker::Dependence::DepName[] = {
+    "NoDep", "Unknown", "Forward", "ForwardButPreventsForwarding", "Backward",
+    "BackwardVectorizable", "BackwardVectorizableButPreventsForwarding"};
+
+void MemoryDepChecker::Dependence::print(
+    raw_ostream &OS, unsigned Depth,
+    const SmallVectorImpl<Instruction *> &Instrs) const {
+  OS.indent(Depth) << DepName[Type] << ":\n";
+  OS.indent(Depth + 2) << *Instrs[Source] << " -> \n";
+  OS.indent(Depth + 2) << *Instrs[Destination] << "\n";
+}
+
 bool LoopAccessInfo::canAnalyzeLoop() {
     // We can only analyze innermost loops.
   if (!TheLoop->empty()) {
     emitAnalysis(LoopAccessReport() << "loop is not the innermost loop");
     return false;
   }
 
   // We must have a single backedge.
if (PtrRtCheck.empty())
       OS.indent(Depth) << "Memory dependences are safe\n";
     else
       OS.indent(Depth) << "Memory dependences are safe with run-time checks\n";
   }
 
   if (Report)
     OS.indent(Depth) << "Report: " << Report->str() << "\n";
 
-  // FIXME: Print unsafe dependences
+  if (auto *InterestingDependences = DepChecker.getInterestingDependences()) {
+    OS.indent(Depth) << "Interesting Dependences:\n";
+    for (auto &Dep : *InterestingDependences) {
+      Dep.print(OS, Depth + 2, DepChecker.getMemoryInstructions());
+      OS << "\n";
+    }
+  } else
+    OS.indent(Depth) << "Too many interesting dependences, not recorded\n";
 
   // List the pair of accesses need run-time checks to prove independence.
   PtrRtCheck.print(OS, Depth);
   OS << "\n";
 }
 
 const LoopAccessInfo &
 LoopAccessAnalysis::getInfo(Loop *L, const ValueToValueMap &Strides) {

test/Analysis/LoopAccessAnalysis/unsafe-and-rt-checks-no-dbg.ll

-; RUN: opt -loop-accesses -analyze < %s | FileCheck %s
-
-; FIXME: This is the non-debug version of unsafe-and-rt-checks.ll not
-; requiring "asserts".  Once we can check memory dependences without -debug,
-; we should remove this test.
-
-; Analyze this loop:
-;   for (i = 0; i < n; i++)
-;    A[i + 1] = A[i] * B[i] * C[i];
-
-target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
-target triple = "x86_64-apple-macosx10.10.0"
-
-; CHECK: Report: unsafe dependent memory operations in loop
-
-; CHECK: Run-time memory checks:
-; CHECK-NEXT: 0:
-; CHECK-NEXT:   %arrayidxA_plus_2 = getelementptr inbounds i16* %a, i64 %add
-; CHECK-NEXT:   %arrayidxB = getelementptr inbounds i16* %b, i64 %storemerge3
-; CHECK-NEXT: 1:
-; CHECK-NEXT:   %arrayidxA_plus_2 = getelementptr inbounds i16* %a, i64 %add
-; CHECK-NEXT:   %arrayidxC = getelementptr inbounds i16* %c, i64 %storemerge3
-
-@n = global i32 20, align 4
-@B = common global i16* null, align 8
-@A = common global i16* null, align 8
-@C = common global i16* null, align 8
-
-define void @f() {
-entry:
-  %a = load i16** @A, align 8
-  %b = load i16** @B, align 8
-  %c = load i16** @C, align 8
-  br label %for.body
-
-for.body:                                         ; preds = %for.body, %entry
-  %storemerge3 = phi i64 [ 0, %entry ], [ %add, %for.body ]
-
-  %arrayidxA = getelementptr inbounds i16* %a, i64 %storemerge3
-  %loadA = load i16* %arrayidxA, align 2
-
-  %arrayidxB = getelementptr inbounds i16* %b, i64 %storemerge3
-  %loadB = load i16* %arrayidxB, align 2
-
-  %arrayidxC = getelementptr inbounds i16* %c, i64 %storemerge3
-  %loadC = load i16* %arrayidxC, align 2
-
-  %mul = mul i16 %loadB, %loadA
-  %mul1 = mul i16 %mul, %loadC
-
-  %add = add nuw nsw i64 %storemerge3, 1
-  %arrayidxA_plus_2 = getelementptr inbounds i16* %a, i64 %add
-  store i16 %mul1, i16* %arrayidxA_plus_2, align 2
-
-  %exitcond = icmp eq i64 %add, 20
-  br i1 %exitcond, label %for.end, label %for.body
-
-for.end:                                          ; preds = %for.body
-  ret void
-}

test/Analysis/LoopAccessAnalysis/unsafe-and-rt-checks.ll

 ; RUN: opt -loop-accesses -analyze < %s | FileCheck %s
-; RUN: opt -loop-accesses -analyze -debug-only=loop-accesses < %s 2>&1 | FileCheck %s --check-prefix=DEBUG
-; REQUIRES: asserts
 
 ; Analyze this loop:
 ;   for (i = 0; i < n; i++)
 ;    A[i + 1] = A[i] * B[i] * C[i];
 
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.10.0"
 
 ; CHECK: Report: unsafe dependent memory operations in loop
-
-; DEBUG: LAA: Distance for   %loadA = load i16* %arrayidxA, align 2 to   store i16 %mul1, i16* %arrayidxA_plus_2, align 2: 2
-; DEBUG-NEXT: LAA: Failure because of Positive distance 2
-
+; CHECK-NEXT: Interesting Dependences:
+; CHECK-NEXT:   Backward:
+; CHECK-NEXT:     %loadA = load i16* %arrayidxA, align 2 ->
+; CHECK-NEXT:     store i16 %mul1, i16* %arrayidxA_plus_2, align 2
 ; CHECK: Run-time memory checks:
 ; CHECK-NEXT: 0:
 ; CHECK-NEXT:   %arrayidxA_plus_2 = getelementptr inbounds i16* %a, i64 %add
 ; CHECK-NEXT:   %arrayidxB = getelementptr inbounds i16* %b, i64 %storemerge3
 ; CHECK-NEXT: 1:
 ; CHECK-NEXT:   %arrayidxA_plus_2 = getelementptr inbounds i16* %a, i64 %add
 ; CHECK-NEXT:   %arrayidxC = getelementptr inbounds i16* %c, i64 %storemerge3