4 files changed, 82 insertions, 1 deletions
diff --git a/polly/include/polly/ScopDetectionDiagnostic.h b/polly/include/polly/ScopDetectionDiagnostic.h
index f53855c50a7..226ed9e9993 100644
--- a/polly/include/polly/ScopDetectionDiagnostic.h
+++ b/polly/include/polly/ScopDetectionDiagnostic.h
@@ -67,6 +67,7 @@ enum class RejectReasonKind {
   CFG,
   InvalidTerminator,
   IrreducibleRegion,
+  UnreachableInExit,
   LastCFG,
 
   // Non-Affinity
@@ -230,6 +231,30 @@ public:
 };
 
 //===----------------------------------------------------------------------===//
+/// Captures regions with an unreachable in the exit block.
+class ReportUnreachableInExit : public ReportCFG {
+  BasicBlock *BB;
+  DebugLoc DbgLoc;
+
+public:
+  ReportUnreachableInExit(BasicBlock *BB, DebugLoc DbgLoc)
+      : ReportCFG(RejectReasonKind::UnreachableInExit), BB(BB), DbgLoc(DbgLoc) {
+  }
+
+  /// @name LLVM-RTTI interface
+  //@{
+  static bool classof(const RejectReason *RR);
+  //@}
+
+  /// @name RejectReason interface
+  //@{
+  virtual std::string getMessage() const override;
+  virtual std::string getEndUserMessage() const override;
+  virtual const DebugLoc &getDebugLoc() const override;
+  //@}
+};
+
+//===----------------------------------------------------------------------===//
 /// Base class for non-affine reject reasons.
 ///
 /// Scop candidates that violate restrictions to affinity are reported under
diff --git a/polly/lib/Analysis/ScopDetection.cpp b/polly/lib/Analysis/ScopDetection.cpp
index a637afa5a41..690655201a1 100644
--- a/polly/lib/Analysis/ScopDetection.cpp
+++ b/polly/lib/Analysis/ScopDetection.cpp
@@ -1428,6 +1428,13 @@ bool ScopDetection::isValidRegion(DetectionContext &Context) const {
     return false;
   }
 
+  DebugLoc DbgLoc;
+  if (isa<UnreachableInst>(CurRegion.getExit()->getTerminator())) {
+    DEBUG(dbgs() << "Unreachable in exit\n");
+    return invalid<ReportUnreachableInExit>(Context, /*Assert=*/true,
+                                            CurRegion.getExit(), DbgLoc);
+  }
+
   if (!CurRegion.getEntry()->getName().count(OnlyRegion)) {
     DEBUG({
       dbgs() << "Region entry does not match -polly-region-only";
@@ -1445,7 +1452,6 @@ bool ScopDetection::isValidRegion(DetectionContext &Context) const {
   if (!allBlocksValid(Context))
     return false;
 
-  DebugLoc DbgLoc;
   if (!isReducibleRegion(CurRegion, DbgLoc))
     return invalid<ReportIrreducibleRegion>(Context, /*Assert=*/true,
                                             &CurRegion, DbgLoc);
diff --git a/polly/lib/Analysis/ScopDetectionDiagnostic.cpp b/polly/lib/Analysis/ScopDetectionDiagnostic.cpp
index b2b566bdffd..ca70018e8fb 100644
--- a/polly/lib/Analysis/ScopDetectionDiagnostic.cpp
+++ b/polly/lib/Analysis/ScopDetectionDiagnostic.cpp
@@ -44,6 +44,7 @@ using namespace llvm;
 llvm::Statistic RejectStatistics[] = {
     SCOP_STAT(CFG, ""),
     SCOP_STAT(InvalidTerminator, "Unsupported terminator instruction"),
+    SCOP_STAT(UnreachableInExit, "Unreachable in exit block"),
     SCOP_STAT(IrreducibleRegion, "Irreducible loops"),
     SCOP_STAT(LastCFG, ""),
     SCOP_STAT(AffFunc, ""),
@@ -190,6 +191,24 @@ bool ReportInvalidTerminator::classof(const RejectReason *RR) {
 }
 
 //===----------------------------------------------------------------------===//
+// UnreachableInExit.
+
+std::string ReportUnreachableInExit::getMessage() const {
+  std::string BBName = BB->getName();
+  return "Unreachable in exit block" + BBName;
+}
+
+const DebugLoc &ReportUnreachableInExit::getDebugLoc() const { return DbgLoc; }
+
+std::string ReportUnreachableInExit::getEndUserMessage() const {
+  return "Unreachable in exit block.";
+}
+
+bool ReportUnreachableInExit::classof(const RejectReason *RR) {
+  return RR->getKind() == RejectReasonKind::UnreachableInExit;
+}
+
+//===----------------------------------------------------------------------===//
 // ReportIrreducibleRegion.
 
 std::string ReportIrreducibleRegion::getMessage() const {
diff --git a/polly/test/ScopDetectionDiagnostics/ReportUnreachableInExit.ll b/polly/test/ScopDetectionDiagnostics/ReportUnreachableInExit.ll
new file mode 100644
index 00000000000..b775d2886f1
--- /dev/null
+++ b/polly/test/ScopDetectionDiagnostics/ReportUnreachableInExit.ll
@@ -0,0 +1,31 @@
+; RUN: opt %loadPolly -polly-detect -analyze < %s \
+; RUN:     -pass-remarks-missed="polly-detect" 2>&1 | FileCheck %s
+
+; void f(long A[], long N) {
+;   long i;
+;   for (i = 0; i < N; ++i)
+;     A[i] = i;
+;   unreachable()
+; }
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+
+define void @f(i64* %A, i64 %N) nounwind {
+entry:
+  fence seq_cst
+  br label %for.i
+
+for.i:
+  %indvar = phi i64 [ 0, %entry ], [ %indvar.next, %for.i ]
+  %scevgep = getelementptr i64, i64* %A, i64 %indvar
+  store i64 %indvar, i64* %scevgep
+  %indvar.next = add nsw i64 %indvar, 1
+  %exitcond = icmp eq i64 %indvar.next, %N
+  br i1 %exitcond, label %return, label %for.i
+
+return:
+  fence seq_cst
+  unreachable
+}
+
+; CHECK: Unreachable in exit block